JP2867160B2 - Non-slip varnish, non-slip processing method using the same, and method for producing non-slip corrugated cardboard - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention provides a non-slip varnish for preventing paper containers such as cardboard and cartons and various paper bags from collapsing, and particularly imparts heat resistance (corrugator suitability). The present invention relates to a non-slip varnish and a non-slip processing method using the non-slip varnish.

<Prior art and its problems> Agricultural products, marine products and other various foods, various industrial products, and the like are packaged and transported in paper containers such as cardboard and cartons or various paper bags.

In recent years, the efficiency of logistics such as automation of various packaging lines and palletization of transport lines has been advanced, and collapse of cargo due to slippage of cardboard cases and the like has become a serious problem. Collapse of a palletized cardboard case or the like can be prevented by banding or shrinking. However, it is costly, and low cost and highly safe slip prevention is desired.

Conventionally, in order to prevent the slippage of these paper containers and paper bags, a slip varnish as described below has been used. For example, the entire surface of a corrugated cardboard case, or the top surface and / or the laminated surface.
Or it was partially printed or coated on the ground.

These non-slip varnishes include an adhesive type (which retains adhesiveness even in a dry state after being coated on a paper container or the like and exerts an anti-slipping effect by this adhesive force) and a non-adhesive type (paper container). By applying an appropriate treatment such as heating and foaming as necessary, a fine unevenness is formed on the surface, and the unevenness physically engages to improve the coefficient of friction and prevent slippage. thing)
Was commonly used.

As the adhesive type non-slip varnish, an acrylic copolymer having adhesiveness or an emulsion of ethylene / vinyl acetate copolymer is exclusively used, and has been printed and coated by an appropriate printing or coating means. Also,
Solid resins such as ethylene / vinyl acetate copolymer are also used,
It was applied by heating and melting in a special hot melt coating apparatus.

Further, a non-slip coating comprising a rubber latex and an aqueous adhesive has been proposed.

On the other hand, the latter non-adhesive type is prepared by mixing fine inorganic particles such as silicic acid anhydride or a foaming agent which foams by heating in a resin binder such as an aqueous ink or an aqueous paint. After printing / coating by printing or coating means, an uneven surface was formed by the fixed fine particles or foaming agent particles which had been expanded in volume by heating.

<Problems to be Solved by the Invention> However, in the above-mentioned adhesive type, since the coated surface after drying has adhesiveness, blocking occurs, and the surface of a paper container or the like is damaged. This greatly reduces the commercial value of paper containers, for example, by adhering and soiling.

In the case of copolymer emulsions having various adhesive properties, there is a problem that a slip prevention effect cannot be obtained if an attempt is made to prevent the occurrence of blocking.In the case of a solid resin, the emulsion is heated and melted. Since special equipment is required, paper containers and paper bag printing machines cannot be used as they are.
There was a problem that the working efficiency was reduced.

In the case of a non-slip coating comprising a rubber latex and an aqueous adhesive, an anti-blocking effect can be expected to some extent, but the friction resistance is not sufficient and has a problem.

In the case of the latter non-adhesive type, the initial anti-slip effect can be expected to some extent, but the anti-slip effect is extremely reduced when reloading is repeated, and the anti-slipping effect is lacking. It was not enough.

Furthermore, in the conventional non-slip varnish, heat resistance is not sufficient, for example, in the production of corrugated cardboard, pre-printed and coated and non-slip varnish on the liner for the production of corrugated cardboard, and the core, back liner with corrugator. When applied to a bonding system, it has the following problems.

That is, in the case of the adhesive type, since the coated surface after drying needs to exhibit adhesiveness, the softening point and molecular weight of the resin used are limited, and the heat-resistant temperature cannot be increased. . Therefore, when these varnishes are applied to each other in a corrugator using a surface liner coated with the varnish, the resin is softened, and hot plate stains are generated, and further, cardboard is damaged. On the other hand, when the softening point of the resin is raised to a sufficient heat-resistant temperature, the effect of preventing slippage is reduced, and the conventional adhesive-type non-slip varnish cannot be applied to this method.

On the other hand, the non-adhesive type is one in which the unevenness is smoothed due to friction with the hot plate in the corrugator, resulting in a remarkable decrease in the anti-slip effect, and is similarly unsuitable for such a cardboard manufacturing system. Was something.

The present invention is intended to solve the above-mentioned problems of the conventional anti-slip varnish, and has a more excellent anti-slip effect, as well as a varnish having excellent blocking resistance and friction resistance, and having heat resistance in a corrugator. Another object of the present invention is to provide a method for preventing slippage using the same, and a method for manufacturing a cardboard subjected to slippage processing.

<Means for Solving the Problem> The present invention corresponds to an improved adhesive-type non-slip varnish, and the present invention relates to an aqueous adhesive having a glass transition temperature in a specific range and an alkali-soluble aqueous solution. An object of the present invention is to provide a non-slip varnish characterized by further adding a specific ratio of a fine particle inorganic filler to a mixture obtained by mixing a resin and a specific ratio.

The water-based pressure-sensitive adhesive used in the anti-slip varnish according to the present invention needs to have a property of imparting tackiness even in a dry state after being applied to a paper container or the like, and has sufficient compatibility with the alkali-soluble water-soluble resin described below. Must have As the aqueous pressure-sensitive adhesive that can be used for such a purpose, a pressure-sensitive adhesive having a glass transition temperature (Tg) of 5 ° C or lower, more preferably 0 ° C to -40 ° C, can be used. Tg is 5
When the temperature exceeds ℃, the slip prevention effect is not sufficient, and when the temperature is lower than −40 ° C., problems such as easy occurrence of blocking occur.

As the aqueous pressure-sensitive adhesive which is one component of the anti-slip varnish according to the present invention, an aqueous emulsion such as an ethylene / vinyl acetate copolymer emulsion, an acrylic copolymer emulsion, a urethane emulsion, and a rubber latex can be used. .

Ethylene / vinyl acetate copolymer emulsion (hereinafter simply referred to as EVA emulsion) requires the property of imparting tackiness even in the dry state after coating on paper containers, etc., and alkali-soluble water-soluble resin described below. Must have sufficient compatibility with

EVA emulsions having a viscosity of 300 to 5,000 centipoise and forming a film at room temperature can be used as such an EVA emulsion.

If the viscosity of the emulsion is out of the above range, those which do not have sufficient printability and do not form a film at room temperature require a special heating device, and are not preferable in terms of working steps.

Specific examples of EVA emulsions having these properties include Polysol EVA P-20, P-3 (manufactured by Showa Polymer Co., Ltd.), Denka EVA Tex # 20, # 60 (manufactured by Denki Kagaku Kogyo), Sumikaflex 400, 401, 450, 610, 460 (manufactured by Sumitomo Chemical Co., Ltd.) and the like. These emulsions are in the range of 35-60 solids.

In addition, the acrylic copolymer emulsion has the above-mentioned properties as a pressure-sensitive adhesive, and includes (meth) acrylic acid alkyl esters such as methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, and t-butyl. , Hexyl, 2-ethylhexyl, decyl, lauryl and other esters having a linear or side chain alkyl group, if necessary, styrenes, (meth) acrylic acid, unsaturated acids such as maleic acid, and other polymerizable compounds Examples thereof include those obtained by emulsion polymerization of a vinyl compound and the like.

As the urethane emulsion, a self-emulsifying type synthesized from a polyol and an organic diisocyanate or an emulsion having tackiness dispersed in the presence of an activator can be used.
It is at 40 ° C.

Specific examples of urethane emulsions having these properties include Suncure 776, 822A, 849, 867, and 889 (manufactured by Gunze Sangyo Co., Ltd.). The solids content of these emulsions ranges from 35-60.

As the rubber latex, natural rubber or a synthetic rubber latex selected from styrene / butadiene rubber, polychloroprene rubber, nitrile rubber or polyisoprene rubber can be used, and these can be used alone or in the form of a mixture.

These rubber latexes are alkaline (usually having a pH of 7 to 12) in a solid content range of 40 to 60% by weight.

Among the water-based pressure-sensitive adhesives exemplified above, urethane-based emulsions and rubber latex are difficult to obtain high friction resistance, and in applications where this suitability is important, EVA emulsions or acrylic copolymer emulsions are used. It is desirable to use it.

As the alkali-soluble water-soluble resin used in combination with the above-mentioned water-based pressure-sensitive adhesive, those having a molecular weight of 5,000 to 60,000, and those having an acid value of 80 to 300 are preferable. If the molecular weight is 5,000 or less, the anti-blocking effect is inferior, if it is 60,000 or more, there is a problem in solubility and printability.If the acid value is 80 or less, it becomes difficult to make water-soluble, and conversely. If it is more than 300, the water resistance or the sliding effect is inferior.

Also, the Tg of the alkali-soluble aqueous resin is 80 ° C or higher,
More preferably it is necessary to be 100 ℃ or more, Tg
When it is low, it is difficult to obtain a sufficient antiblocking effect and heat resistance.

Specific examples of these alkali-soluble water-soluble resins include:
Styrene / maleic acid copolymer, styrene / acrylic copolymer, rosin-modified maleic resin, acrylic resin, maleic resin and the like can be exemplified, and these can be used alone or in combination of two or more.

In the anti-slip varnish according to the present invention, the mixing ratio of the aqueous pressure-sensitive adhesive and the alkali-soluble water-soluble resin is important, and the solid content of the latter is 40 to 100 parts by weight with respect to the solid content of 100 parts by weight. If the ratio of the former is required to be in the range of parts by weight, and if the former ratio is high, the blocking resistance and heat resistance become problems, and if the ratio is opposite, the non-slip effect becomes a problem.

Further, as the inorganic fine particle filler, 2 to 10% by weight, preferably 2 to 8% by weight can be added to the non-slip varnish. In addition, when it is 2% or less, blocking resistance and heat resistance are poor, and suitability for corrugator is not sufficient. On the other hand, when the content is 10% or more, problems such as whitening, decrease in fluidity, and sedimentation of printed matter may occur. Further, the particle size of these inorganic fillers, 1 ~ 20μ, more preferably 2 ~ 10μ
Can be used. If the particle size is smaller than the range, the anti-blocking effect cannot be obtained.
A problem arises in coating suitability. Specific examples of the inorganic filler include silica powder, silica gel, glass powder, talc,
Clay, calcium carbonate, magnesium carbonate, zinc white,
Barium sulfate can be exemplified.

The anti-slip varnish according to the present invention has the above three components as main components, but if necessary, an antifoaming agent,
Various additives can be added to adjust viscosity, adjust drying, or improve printability.

<Operation> The non-slip varnish according to the present invention is obtained by further mixing a fine particle inorganic filler in a specific ratio with respect to a mixture obtained by mixing an aqueous pressure-sensitive adhesive having a glass transition temperature in a specific range and an alkali-soluble water-soluble resin in a specific ratio. It is characterized by being added, and its action can be considered as follows.

In other words, in the case of the conventional adhesive type non-slip varnish, an adhesive layer is formed on the surface of the coated varnish, and thus the anti-slipping effect was obtained. It could not be raised. In contrast, the varnish according to the present invention is:
Although the pressure-sensitive adhesive ratio was originally raised to the point where blocking would occur, the inorganic filler was added in a predetermined amount to form an inorganic filler layer uniformly on the surface of the coated varnish. It is thought that it acts as a barrier to prevent direct contact and prevent the occurrence of a blocking phenomenon.
In addition, when a cardboard or the like is laminated and a load is applied, the inorganic filler is pushed into the layer, the adhesive layer comes into direct contact and exhibits a high anti-slip effect, but when the load is removed, the inorganic filler is extruded. It is considered that a peeling phenomenon in units of microns occurs to prevent the occurrence of blocking.

In addition, for heat resistance and corrugator resistance, the inorganic filler layer uniformly formed on the coated varnish surface,
It is considered that as a result of preventing direct contact between the hot plate and the adhesive layer, generation of hot plate stains and reduction of the slip prevention effect do not occur.

Now, the application of the anti-slip varnish according to the present invention can be performed by means such as roller coating or spraying after box making or bag making, but from the viewpoint of work efficiency, paper containers, paper bags, etc. It is preferable to carry out within the printing step. More specifically, the non-slip varnish can be applied simultaneously with printing on a paper container or the like in the last printing unit that has a surplus printing machine.

Next, a description will be given of a method of manufacturing corrugated cardboard using the non-slip varnish according to the present invention. The non-slip varnish according to the present invention exhibits an excellent non-slip effect when applied to a cardboard or a paper box, but also has high heat resistance to a hot plate of a corrugator. Therefore, the non-slip varnish according to the present invention is extremely effective when applied to a preprinting method which has recently been used in cardboard production. That is, in the present invention, after applying the anti-slip varnish according to the present invention to the surface of the surface liner printed in a rotary printing format, the front liner, the core and the back liner are bonded with a corrugator machine to obtain a cardboard. An object of the present invention is to provide a method for producing a cardboard subjected to a non-slip process.

First, a process of printing in a rotary printing mode on the surface of a front liner used for manufacturing corrugated cardboard will be described.

In the conventional cardboard printing, a front liner, a core, and a back liner are bonded together, and a cardboard cut into an appropriate size is used, and printing is performed by a sheet-fed type flexographic printing machine or the like. On the other hand, in the method of the present invention, printing is continuously performed on a web-like front liner in a rotary printing mode.

In this printing process, there is no restriction as in the conventional printing method such as cardboard printing, and if the printing method is a rotary printing method, flexographic printing, gravure printing, planographic rotary printing, and even rotary screen printing, etc. Means can be conveniently used.

In recent years, as a method of manufacturing high-grade corrugated cardboard, using aqueous or solvent-based flexo or gravure ink on a web-like surface liner, rotary printing is performed, and the rolled-up material is used as a mill roll stand for a corrugation machine surface liner. And a method of manufacturing corrugated cardboard by so-called preprinting, which is attached to a core and a back liner.

Therefore, printing is performed on the front liner using the various printing inks used therein and the printing machine used for the printing ink, and after the required printing is performed on the front liner, it is wound up. It is also possible to continuously print the front liner and apply the next non-slip varnish inline.In this case, the last printing unit of the printing press is used to apply the non-slip varnish. This can be achieved by utilizing or by incorporating various coating equipment for application after the printing press.

In addition, when applying a non-slip varnish in-line with printing, using means such as roll coating, curtain coating, spray coating, or gravure, flexographic printing,
It can be applied to the entire surface or to a required part. It is also possible to attach the printed front liner to a mill stand of a corrugation machine as it is and apply a non-slip varnish using a liner roll coater or the like installed in the corrugation machine.

Here, using a conventional liner coated with a non-slip varnish, when performing lamination with the core and the back liner in a corrugator machine, the temperature of the hot plate is 160 to 1
At 90 ° C., deterioration of the anti-slip effect occurs, which causes a problem that the softened resin causes hot plate contamination and significantly lowers the commercial value of corrugated cardboard. If used, the anti-slip effect is not reduced, and the problem of hot plate contamination does not occur.

Therefore, when the method of the present invention is carried out, when using a surface liner that has been previously printed and coated with a non-slip varnish, the printed and coated surface wound on a mill roll stand for the surface liner is used. If the liner is installed and the varnish is not applied, it is applied to the printed front liner by a coating device installed before or after the preheater for the front liner. Then, a corrugated cardboard laminated with the back liner and subjected to a desired non-slip process is produced.

In the practice of the method of the present invention, there are few cases where non-printed cardboard is manufactured, and in many cases a printed front liner is bonded, so a cutting device that cuts based on a printed design is installed. There is a need. Necessary cutting and the like are performed by the above-mentioned cutting device, so that a target cardboard with anti-slip processing can be obtained.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.

<Examples> Here, the components (aqueous pressure-sensitive adhesive, water-soluble resin, and inorganic filler) of the anti-slip varnish manufactured in the examples will be described.

Aqueous adhesive Adhesive A: Polysol EVA P-20, manufactured by Showa Polymer (viscosity 1500 cps, solid content 58%, Tg-15 ° C) Adhesive B: acrylic emulsion, Movinyl 937 (manufactured by Hoechst Gosei Co., Ltd.) (solid 60%, Tg. -40 ° C) Adhesive C: manufactured by Nippon Synthetic Rubber Co., Ltd., SBR latex No. 0598 (solid content 50%, Tg. -20 ° C) Water-soluble resin solution Water-soluble resin A: methyl methacrylate, An aqueous ammonia solution of an alkali-soluble resin composed of 65.1% by weight, methacrylic acid, 23.1% by weight, and 8.8% by weight of styrene (water-soluble resin A).
The solid content was 35% by weight and Tg. 121 ° C.

Water-soluble resin B: An aqueous ammonia solution of an alkali-soluble resin composed of methyl methacrylate, 52.4% by weight, acrylic acid, 21.8% by weight, styrene 11.8% by weight, butyl acrylate, 14.0% by weight (water-soluble resin B). In addition, solid content 35% by weight, T
g. 69.8 ° C.

Fine particle filler: silicon dioxide, syloid (manufactured by Fuji Devison) Examples 1 to 8 and Comparative Examples 1 to 5 The pressure-sensitive adhesives A to C, the water-soluble resins A and B, and the fine particle filler described above are shown in Table 1. The mixture was mixed so as to be blended, and each of the non-slip varnishes was adjusted, and the following evaluation test was performed.

Evaluation test Using each of the slip varnishes obtained in the slip varnish production example, using a bar coater, apply to the K liner for corrugated cardboard in a solid form so that the coating amount becomes about 4 g / m ^2. Humidity was controlled at 60 ° C. and a humidity of 60% for one day, and the slip angle was measured in accordance with the tilt test specified in TAPPI.

In addition, for the blocking, the humidity was similarly adjusted at high temperature and high humidity (40 ° C, humidity 90%), and the varnished surfaces were overlapped.
Evaluate under a load of 5 kg / 25 cm ² .

In the case of a liner having no varnish applied, it was similarly evaluated as a blank.

The heat resistance is evaluated by applying a varnished surface to an aluminum foil, pressing the varnish at 180 ° C. under a load of 5 kg / cm ² for 3 seconds, and evaluating the degree of transfer of the varnish to aluminum.

Regarding the rub resistance, each varnish was coated on a K liner for corrugated cardboard printed with an aqueous flexo ink with a bar coater so that the coating amount was about 4 g / m ² in a solid state. Vibration type friction tester, 500g load,
Under the condition of 500 times, な い was given when no stain was generated, Δ was given when slight stain was caused, and X was given when much stain was found.

Further, using a water-based flexo ink, a K liner for corrugated cardboard printed in a rotary printing form is coated with the above-mentioned heat-resistant non-slip varnish, and this is used as a front liner and bonded to a core and a back liner with a corrugator. Then, a corrugated cardboard is manufactured, and the presence or absence of contamination on a hot plate and the slip angle after passing through a corrugator are measured.

 In addition, the result of each said evaluation is shown in Table-1.

<Effects> As is clear from the above description, the anti-slip varnish according to the present invention has an extremely high anti-slip effect as compared with the conventional adhesive type anti-slip varnish, and has excellent blocking resistance and heat resistance. Therefore, the present invention can be effectively applied to a so-called preprint type corrugated cardboard manufacturing method which has been recently implemented.

Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI C09D 131/04 C09D 131/04 SB 133/00 133/00 (58) Field surveyed (Int.Cl. ⁶ , DB name) C09D 5 / 00 B65D 5/62 B63B 25/24

Claims (8)

(57) [Claims] 1. An alkali-soluble water-soluble resin having a glass transition temperature of 80.degree.
A non-slip varnish characterized in that 2 to 10% by weight (solid content) of a fine particle inorganic filler is added to a non-slip varnish mainly composed of 0 parts by weight (solid content). 2. The aqueous pressure-sensitive adhesive has a glass transition temperature of 5 ° C.
The non-slip varnish according to claim 1, which is an aqueous emulsion as follows. 3. A non-slip varnish according to claim 2, wherein said aqueous emulsion is selected from an ethylene / vinyl acetate copolymer emulsion and an acrylic copolymer emulsion. 4. The non-slip varnish according to claim 1, wherein the alkali-soluble water-soluble resin has a glass transition temperature of 100 ° C. or higher. 5. A non-slip varnish according to claim 1, wherein said fine particle inorganic filler is silicon dioxide. 6. The paper container or the paper bag according to claim 1, wherein:
A non-slip processing method, comprising applying the non-slip varnish according to the above description to form a non-slip coating. 7. The non-slip processing method according to claim 6, wherein the slip varnish is applied in a printing step of a paper container or a paper bag. 8. A printed corrugated cardboard which is coated with the slip varnish according to claim 1 to a corrugated machine. The corrugated cardboard is then used for laminating the corrugated cardboard with the core and the back liner. A method for producing a cardboard subjected to anti-slip processing, characterized by producing a cardboard.