JP2743898B2 - Container sheet with anti-slip properties - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a box in which slip is prevented,
Alternatively, the present invention relates to a sheet for manufacturing a container such as a bag, and more particularly to a container sheet to which an anti-slip agent has been applied in advance before box making, bag making, or cardboard bonding.

[0002]

2. Description of the Related Art In order to prevent a box or a bag stacked on a pallet from being dislodged, it is conventional to apply an anti-slip agent or a bag to the bag. There are known a method in which a soft resin or rubber is applied and the material is made of tack to prevent slippage, and a method in which inorganic particles are applied together with a binder. Specifically, (1) applying a solution or dispersion of soft resin or rubber
Method of drying, (2) in addition to the above, mixing foamable hollow particles made of a soft synthetic resin, a method of applying and drying,
(3) This method involves coating and drying inorganic particles having large irregularities together with a binder. As an example of (1), JP-A-48-60090 discloses a method of applying atactic polypropylene or an ethylene / vinyl acetate copolymer to a cardboard box. As an example of (2), see Japanese Utility Model Publication No. 57-29323,
Non-slip paper in which foaming paint is layered on paper or sheet is disclosed. Further, JP-A-60-21419 discloses that a hollow sphere of a thermoplastic resin is dispersed in a binder, applied and dried, and the hollow sphere is formed. A technique has been disclosed in which a remarkable anti-slip effect is provided by the elastic effect of the above.

[0003]

In the conventional method, coating and drying are usually performed after box making or bag making. However, container forming such as a printing process on a base paper or a paper making process (box forming, manufacturing, etc.). If the coating can be performed at a stage before the bag process is collectively referred to as container molding), the process can be simplified and energy resources can be saved. However, if the coating is performed at the stage of the base paper before the container is formed, in the methods of (1) and (2), the coated material that has been heated during box making, bag making, or cardboard bonding becomes sticky, Troubles adhering to rolls or belts occur. In particular, the method (2) has a drawback that the soft polymer hollow particles are remarkably foamed, thereby impairing the aesthetics of printing. Further, even when heat is not necessarily applied in the post-process, for example, winding of kraft paper coated with an adhesive resin on kraft paper for bags easily causes blocking. In the method (3), if a soft binder is used, there is the same disadvantage as described above. When a hard (relatively high softening point) resin is used as the binder and the slip is prevented by the effect of the unevenness of the inorganic particles, Although the problem of adhesion of the sticky substance is eliminated, there is a problem that the roll may be damaged by the particles in the subsequent process or the particles may peel off. If the binder does not have tackiness, a large amount of irregular particles are required to prevent slippage, and thus the aesthetics of printing is also impaired. Therefore, there is no blocking at the time of winding, there is no fear of sticking of the sticky substance due to heat in the subsequent process, the particles do not peel off, the roll is not damaged, and the sliding without impairing the aesthetics of printing. It has been desired to develop a container sheet having prevention properties.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. The container sheet having anti-slip properties of the present invention is provided with a coating layer containing the following components (a) and (b) on one surface of a substrate. (A) After keeping transparent inorganic or organic particles having a particle diameter of 2 μm or less in the range of 20 to 40% by weight in the total coating layer, they are mixed with a synthetic resin binder, and the mixture starts to flow. Temperature of 100 ° C or higher. (B) Foamable hollow particles of a synthetic resin having a softening point of 100 ° C. or more occupying 0.5 to 2% of the entire coating layer in weight ratio.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The hollow particles are not necessarily foamed at the stage of the container sheet of the present invention, and may be partially or entirely foamed. As the transparent inorganic particles used in the present invention, various silicas can be mentioned. As the transparent organic particles, for example, synthetic resin powder such as polystyrene is used. The layer imparting anti-slip properties of the present invention is usually a coating layer formed by various coaters, but may be a layer formed by impregnation, spraying or the like. Transparent inorganic or organic particles must have a weight ratio of at least 20% in the total coating layer in order to form many fine irregularities on the surface of the coating layer and to prevent blocking and slippage. In order not to impair the aesthetics of the printing performed, the content needs to be 40% or less. It is also necessary to prevent the flow of the entire coating layer at a high temperature and to prevent unevenness due to foaming of hollow particles from flowing. The synthetic resin binder must not flow at the highest temperatures of the entire process in which the sheet of the invention is made and used. Normally, the drying process for coating and printing should be at least 100 ° C.
About 140 ° C. when the temperature is high. Also, the surface temperature of the paper when pasting the double backer side of the cardboard is
Even at a high temperature, it is about 160 ° C. Therefore, a coating layer that does not flow at least at about 100 ° C. is required. It is necessary to evaluate the flow at the time of use not with the resin alone but with the resin mixed with the particles. The state of change due to the temperature of the thermoplastic resin is a glassy region, a glass transition region, a rubbery region,
The resin can be used in the present invention, which is divided into four flow regions, and needs to be in a rubbery region at a temperature of 100 ° C. or more, preferably 100 to 160 ° C., in a state where particles are mixed. The location of each of the four areas depends on the time scale to be measured. However, since tackiness in ordinary work is a problem, the measurement is performed while increasing the temperature.
In a dynamic viscoelasticity measurement on a time scale of about 1 second, when the relaxation modulus is between 10 ^{6 and} 10 ⁷ dyn / cm ² , the area where the temperature change is small and the flow does not occur is defined as a rubbery area. I do. And the relaxation elastic modulus is 10 ⁶ dyn / cm ²
The temperature at which the temperature suddenly decreases is defined as the flow start temperature of the present invention. Many resins have a rubbery region between 100 and 160 ° C. as a property of the resin itself, but such a resin is a hard film at room temperature and is not preferable as an anti-slip agent. It is necessary to choose something soft even at room temperature. Therefore, a resin having a glass transition temperature of about −30 ° C. to 10 ° C. is cross-linked at a rate of about one in 50 to 100 in a monomer unit, so that a rubber-like region is maintained without causing a flow even at a high temperature. Must be something. Such examples include polymethyl acrylate, polyethyl acrylate, styrene / butyl acrylate copolymer (styrene 50% or less), vinyl acetate / butyl acrylate copolymer (vinyl acetate 80% or less), methyl methacrylate / ethyl There is an acrylic copolymer such as an acrylate copolymer (50% or more ethyl acrylate) in which a functional group capable of causing a crosslinking reaction is copolymerized in a monomer ratio of 0.5 to 1.5%. Examples of the functional group include an epoxide group, an acid anhydride, an amino group, a carboxyl group, a hydroxyl group, an amide group, an isocyanate group, and the like. good.
In addition, a copolymer such as polyacrylate obtained by copolymerizing the above reactive monomer can be bonded to the surface of silica fine particles using a silane coupling agent, so that the silica fine particles can function as a crosslinking agent. When the surface of the glass fiber is treated and activated with a Lewis acid such as TiCl4 or SnCl4, cationic polymerization is initiated by a complex of the silanol group on the glass surface and the Lewis acid, and styrene or an epoxy resin is graft-polymerized. Therefore, this method may be applied to the silica fine particles of the present invention. The amount of the synthetic resin binder used is 6 in the coating layer.
0 to 90% by weight. The heat-expandable synthetic resin hollow particles used in the present invention are necessary for causing foaming at the time of using the sheet of the present invention or at the time of using the sheet, forming large irregularities, and exhibiting an anti-slip effect. Sufficient anti-slip properties cannot be obtained with only the synthetic resin binder and the fine particles described above. For example, in order to obtain a slip angle of 45 °, it is necessary to add synthetic resin expandable hollow particles. As the synthetic resin foamable hollow particles, for example, styrene, methacrylic acid ester, acrylonitrile / vinylidene chloride copolymer and the like are used.In the present invention, the unevenness is not reduced by flowing in a printing drying step or the like. Softening point is 10
It is necessary to use resin particles having a temperature of 0 ° C. or higher. The softening point here is a recut softening point defined by ASTM-D1525. The particle diameter of the hollow particles is preferably 2 to 20 μm,
It is necessary to add 0.5 to 2% by weight in all the coating layers. If it is 0.5% or less, the anti-slip effect is low, and if it is 2% or more, whitening of the printed surface becomes noticeable, which is not preferable. The coating amount of the entire coating layer is 1 to 5 g / m in total solid content weight.
² is preferred. The base material used in the present invention may be a thin container such as corrugated cardboard, paperboard, or kraft paper, or may be thin printing paper or a plastic film. What provided the coating layer of the present invention on a thin sheet can be used after being laminated on a cardboard. According to the study of the present inventors, if a filler such as starch is undercoated before the application of the anti-slip agent of the present invention, the same degree of anti-slip effect can be obtained. The result is that the coating amount of the anti-slip agent can be reduced by half, which contributes to the cost reduction of the anti-slip agent. In addition, if the application amount is the same, the anti-slip effect can be further enhanced.

[0006]

The effect of the coating layer of the present invention for imparting anti-slip properties is considered as follows. In order to prevent the applied layer from flowing even when receiving heat in a later process, a resin having a high softening point must be used, but such a resin does not flow at high temperatures because it has no anti-slip effect. However, it is necessary to use a resin that is soft even at a low temperature. Therefore, a resin in which the rubber-like region in the viscoelastic behavior of the polymer substance is set to a wide temperature range was used. Further, microscopic irregularities are formed by the fine particles, and a small amount of large irregularities is generated together with the microscopic irregularities, thereby enabling coating without impairing the aesthetic appearance of printing.

[0007]

Examples of the present invention will be described below. Examples 1-5, Comparative Examples 1-2 Corrugated cardboard base paper having a basis weight of 200 g / m ² (Honshu Paper Co., Ltd.)
PFK 200 liner), four-color printing is performed by a five-color flexographic printing machine, and the anti-slip agent having the composition shown in Table 1 below is applied to the bottom and top portions of the cardboard box in the final printing section. Was applied at ² g / m ^{2 and} dried with a food dryer at 120 ° C. for 5 seconds. The polyethyl acrylate-based binder used in the formulation was a copolymer obtained by mixing 1: 1 emulsions of polyethyl acrylate containing 1 mol% of glycidyl acrylate and polyethyl methacrylate containing 1 mol% of dimethylaminoethyl methacrylate. Using.

[0008]

[Table 1]Anti-slip coating compositionSilica Polyethyl acrylate Acrylonitrile / Vinylideweight%Binder weight% Copolymer hollow particles by weight Example 1 30 69 1 Example 2 30 69.5 0.5 Example 3 30 68 2 Example 4 20 79 1 Example 5 38 60 2 Comparative Example 1 30 70 0 Comparative Example 2 10 89 1 Using the obtained cardboard base paper coated with the anti-slip agent,
By the slope method of IS P8147,
Table 2 shows the measurement results of the angle at which the sliding starts.

[0009]

[Table 2]Slope angle at which cardboard base paper starts to slide Unit: degree  First time After 10 repetitions Example 1 60 55 Example 2 53 42 Example 3 60 57 Example 4 50 45 Example 5 60 58 Comparative example 1 45 30 Comparative Example 2 42 30  As is clear from the data shown in Tables 1 and 2, the inorganic particles
20 to 40% by weight and 0.5 to 2% by weight of hollow particles
Examples of the invention dispersed in a lylic ester binder
Is 10 times, which is regarded as a passing point of the anti-slip effect
It is effective when the inclination angle after turning over exceeds 40 °,
Comparative Example 1 without blending empty particles, comparison with less silica blending
Neither of the examples 2 provides the anti-slip effect.

Usually, the anti-slip agent is applied to the top or bottom surface of the box entirely or partially. However, unlike the other anti-slip agents, the anti-slip agent has low adhesiveness, so that the anti-slip agent is used when loading and transporting the box. It is preferable to apply the anti-slip agent of the present invention on the whole or part of the side surface in addition to the top surface and the bottom surface in order to prevent the adjacent boxes from being displaced by the vibration caused by the vibration.

[0011]

As described above, the present invention eliminates the waste of adding a processing step of applying and drying a conventional anti-slip agent for a container after the container is manufactured, and prevents the anti-slip property at the time of forming the base paper or at the stage of printing the base paper. There is a great merit that a container sheet having the following is obtained. For this reason, blocking in the winding state, which has occurred due to the application of the conventional anti-slip agent, adhesion of the sticky substance in the container molding process, dropping of particles for forming irregularities or scratching of the roll surface due to particles, etc. I no longer have to worry about the trouble. In addition, in the case of using a large amount of unfoamed hollow particles, there was a problem that the printed surface was whitened due to foaming.However, in the present invention, a small amount of hollow particles was foamed to exhibit an anti-slip effect. Trouble was solved, too.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-62-60638 (JP, A) JP-A-49-32966 (JP, A) JP-A-62-33633 (JP, A) JP-A 62-60633 73940 (JP, A) JP-A-63-146945 (JP, A)

Claims (2)

(57) [Claims] 1. A container sheet having anti-slip properties, comprising a layer containing the following components (a) and (b) provided on one surface of a substrate. (A) After keeping transparent inorganic or organic particles having a particle diameter of 2 μm or less in a range of 20 to 40% by weight in the total coating layer, the mixture is mixed with a synthetic resin binder, and the mixture flows. A starting temperature of 100 ° C to 160 ° C. (B) Foamable hollow particles of a synthetic resin having a softening point of 100 ° C. or higher. 2. The container sheet according to claim 1, wherein the amount of the expandable hollow particles is in the range of 0.5 to 2% by weight of the entire coating layer.