JPH1135908A - Cold sealing-type packaging material in a roll form - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a roll form of a cold sealing-type packaging material which is resistant to blocking and shows a stable adhesion rendered by a cold sealing agent. SOLUTION: This packaging material is prepared by applying a cold sealing- type adhesive which exerts adhesion when compressed at room temperature, to a base material, especially a paper base material. A rolled form of the packaging material is prepared by adding from 1 to 20 wt.%, organic filler F of which the particle size is from 0.1 to 150 μm, to an adhesive, and applying a cold sealing-type adhesive 2 on the paper base material 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION At room temperature, a cold sealant which can be adhered only by pressing the coated surfaces thereof is applied to a base material such as paper or film, and the coated paper or film is wound into a roll. Regarding the packaging material taken.

[0002]

2. Description of the Related Art A cold sealant does not exhibit tackiness when it is applied to a substrate and dried, but it can be adhered only by pressing the coated surfaces of the sheets to which they have been applied. It is characterized by being able to. Unlike a heat seal that is generally used as a bonding technique of a package, there is no need to heat the sealed portion, so that no time is required for heat transfer, and high-speed packaging is possible. Since it can be packaged without applying heat, it is possible to package content that dislikes heat, for example, chocolate and chocolate-coated confectionery, ice cream, and the like. Also,
In the case of a packaging material using a cold sealant as a sealing material, heat resistance is not required as a base material, and there is no need to heat up the packaging machine because there is a wide selection range of various films, and the sealing time is reduced. Therefore, there is an advantage that the running speed is increased, and the labor and speed of the packaging line can be reduced. Generally used pressure-sensitive adhesive tapes or pressure-sensitive labels have adhesiveness at room temperature and adhere to the surface of other objects, but due to the adhesiveness, the adhesive surface has a release property until use. It is necessary to be in a state of being aligned with the surface. For example, a method is used in which a release paper is interposed or the back surface of the pressure-sensitive adhesive applied surface is subjected to a release treatment so that the pressure-sensitive adhesive surface is flush with the pressure-sensitive adhesive surface. However, the cold sealant is different from the pressure-sensitive adhesive tape and the like in that the coating film after application and drying does not exhibit adhesiveness, but can be adhered by pressing the applied surfaces thereof. Therefore, the laminate coated with the cold seal agent does not require the release paper or the release agent treatment of the back surface. However, conventionally,
When stored in a pressurized state for a long time, for example, when the packaging material coated with a cold sealant is wound up into a roll-shaped material, the winding hardness, the storage temperature, and the storage period when wound up in a roll shape There is a risk of blocking between the coated surface and the non-coated surface depending on conditions such as the length of the film. When blocking in the state of being wound in a roll, even if it is a slight blocking, for example, it becomes a hindrance to stable operation in an automatic packaging machine or the like, and furthermore, when the degree of blocking advances, it becomes impossible to operate. It is. For this reason, conventionally, in the winding process after the application of the cold sealant, care was taken not to solidly wind, care was taken not to raise the temperature during storage and the like, and long-term storage was avoided as much as possible. Further, the back surface of the cold sealant-coated surface may be coated with a release varnish for preventing blocking. The blocking tends to occur particularly in a base sheet such as paper. In plastic films, latex-based adhesives such as cold sealants can be used to dry and coat the cold sealant coating because the film is smooth and, above all, free of active groups that contribute to adhesion, or very little. There is little fear of doing so. On the other hand, in the case of paper base material, the surface is rough and natural pulp fibers are exposed, and it comes into contact with the dry coating film of the cold sealant under pressure. The length may cause the blocking trouble. As an advantage of the packaging material coated with the cold seal agent, the peeling force of the adhesive portion of the cold seal agent is in the range of easy opening by a finger,
Actually, it is practically used for packaging many contents for the purpose of easy opening. In packaging, when the seal is peeled off by hand and opened, it is desirable that the resistance value be as low as possible.However, at the stage of distribution of the product, the physical, chemical or biological Guarantee by reliable sealing is required, and the adjustment of the peeling resistance value of the bonded portion by the cold seal agent is set in consideration of the type of contents, the internal capacity, the age of the user, etc., but the resistance value is set. In the case of the conventional cold sealant, the degree of freedom in design is low, and the resistance value is too weak or too strong. Therefore, a cold seal agent that can easily adjust the peel resistance has been desired.

[0003]

In particular, even when a cold sealant is applied to paper as a base material and wound up in a roll without providing a release varnish layer on the back surface of the base material, no blocking occurs, and the adhesive strength is also low. The present invention provides a technique for a roll of a stable cold seal type packaging material.

[0004]

In order to solve the above-mentioned problems, the present invention relates to a packaging material obtained by applying a cold seal type adhesive which can be adhered by pressing at room temperature to a base material, wherein the adhesive is An organic filler having a particle size of 0.1 to 150 μm is used as a cold sealant mixed with an organic filler in a range of 1 to 20% by weight, and a roll of a packaging material obtained by applying the cold sealant to a paper base material. That could be solved.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a stable cold sealant and a coated material thereof by adding an organic filler to the cold sealant, particularly a paper-based packaging material. It is in the form of a roll.
FIG. 1 is a sectional view and a partially enlarged view of an embodiment of a packaging material to which the cold sealant of the present invention is applied. FIG. 2 is a cross-sectional view of another embodiment of the packaging material coated with the cold sealant of the present invention. FIG. 3 is a perspective view showing an example of a method of storing a roll-shaped material of the cold seal type packaging material of the present invention, in which (a) is an example of direct mounting and (b) is an example of hanging.

The adhesive main component of the cold sealant of the present invention includes natural rubber (NR), esterified natural rubber, styrene butadiene rubber (SBR), chloroprene rubber, polyvinyl acetate, polymethyl methacrylate (PMMA) and the like. Or a mixture thereof. In mixing these pressure-sensitive adhesives, the adhesiveness between the pressure-sensitive adhesives and the substrate can be made larger than the self-adhesiveness while maintaining the self-adhesiveness of the pressure-sensitive adhesives by appropriately adjusting the mixing ratio.

However, as described above, in the laminated material to which the cold sealant is applied, troubles due to blocking occur frequently, and the storage conditions, the period, and the like are limited. It is common practice to apply a cold sealant to a base material such as paper and dry it, supply it as a roll to an automatic packaging machine, and package contents that are deformed or deteriorated by heat. However, when the cold sealant is applied to a base material such as paper and formed into a roll (winding), as described above, depending on storage conditions and the like, the applied surface and the non-applied surface adhere ( (Blocking), and therefore, a release varnish layer was sometimes provided on the non-coated surface (back surface). The cold sealant is a latex in which the above substances are mixed, and the mixing ratio thereof is designed so that the desired adhesive strength is obtained depending on the suitability for processing such as coating, the intended use, and the packaging form. The present inventors have added various organic fillers to the latex, applied and dried on a paper substrate, and
The obtained coated sheet was rolled up in a roll shape, and the blocking property was confirmed by the storage conditions and the like.Without providing a release varnish or the like on the back surface, even if stored under general conditions, the blocking that was conventionally seen was not observed. The present invention was completed after confirming that it did not occur.

As a technique for adding a filler to a cold sealant, for example, the purpose of increasing the re-peeling strength in a three-fold postcard using a cold sealant to conceal personal information, etc., and to improve printability, texture, etc. It has been proposed that various fillers (fillers) be added to the cold seal adhesive composition for the purpose of (Japanese Patent Laid-Open No. 5-29533).
Five). Further, an inorganic filler may be added with silicon dioxide to a cold sealant (Japanese Patent Application Laid-Open No. 8-156967), or a protective layer made of a release varnish is provided on the back surface of the substrate coated with the cold seal adhesive, and The addition of silicon dioxide (JP-A-8-332693) is disclosed. However, when the inorganic filler is added to the cold seal adhesive, the dispersibility is poor compared to the organic filler,
For example, in the case of using silica, if the added amount exceeds 5% by weight, it will not be dispersed. In addition, within the dispersible range, although the effect on the blocking property of the packaging material coated with the cold sealant to which the inorganic filler was added is recognized, the adhesive force depending on the amount added is different from that in the case where the cold sealant with no addition is applied. And it was difficult to adjust the adhesive strength. Therefore, in order to solve the above-mentioned problems, as a result of various studies, by adding a certain amount of an organic filler to the cold sealant containing the adhesive main component, even if the material coated with the cold sealant is wound into a roll shape, It can be stored without causing a blocking accident as described above.

In the present invention, the organic filler to be added to the cold sealant includes polymethyl methacrylate,
Cross-linked polyacrylate, polystyrene, styrene-maleic acid half ester copolymer, styrene- (meth)
Acrylic esters, low-density polyethylene, high-density polyethylene, ethylene-acrylic acid copolymer, phenol, polyurethane and the like can be mentioned. When these organic fillers were added to the cold seal adhesive, it was found that the organic filler was excellent in dispersibility in the cold seal agent and was effective in modifying the coating film of the cold seal adhesive.

As a result of various experiments, the effect was shown in the range of 1 to 20% by weight of the organic filler added to the cold sealant of the present invention. More preferably, it is 2 to 15% by weight. If the amount of the organic filler to be added is less than 1% by weight, there is no effect of preventing blocking, and if the amount exceeds 20% by weight, dispersion becomes difficult, and workability at the time of application becomes poor, Even if it can be applied to a base material, the adhesive force between the applied surfaces is weak and is not practical.

Various materials can be used as the base sheet on which the cold sealant of the present invention is applied. Specifically, the flanges formed of resin such as high-quality paper, glassine paper, parchment paper, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyethylene terephthalate, nylon, etc. Stretched or stretched plastic films, or polypropylene or polyethylene. Dry or wet nonwoven fabrics made of polyester or the like can be given. The surface of the substrate may be smooth or embossed, or may be a rough surface made of fibrous material such as paper. When the cold seal type packaging material of the present invention is formed into a roll, the effect is most remarkably exhibited when the base material is paper. The cold sealant applied to the paper base material blocks when rolled up in a roll shape, and may exhibit a phenomenon of delamination on the back surface of the paper at the time of peeling, but the organic filler of the present invention is added. The use of the cold sealant has a remarkable effect in preventing the blocking. The substrate may be provided with a pattern by printing or the like, or may be printed after applying a cold sealant. Further, a protective layer for protecting a pattern or the like from friction or the like may be provided on the pattern layer formed by printing.

As a method for applying the cold sealant of the present invention, using a coating method such as gravure coat, offset gravure coat, roll coat, reverse roll coat, air knife coat, curtain coat, comma coat, etc. In-line, the coating film is dried and wound into a roll. In the present invention, the base material wound in a roll shape is unwound, the cold seal adhesive is applied and dried by any of the above-mentioned methods, and then wound again, that is, wound in a roll shape. When winding (rewinding) after the above-mentioned application, if the substrate is wound while the tension of the substrate is kept strong, the applied cold seal agent layer is tightly wound around the non-application surface, which causes a blocking phenomenon. For this reason, conventionally, it has been usual to carefully wind up the winding so as not to be excessively hard.
In the case of the packaging material of the present invention in which a cold sealant containing an organic filler was applied to a substrate, the blocking phenomenon in the winding was eliminated, so that the work could be performed stably.

The characteristics of the packaging material to which the cold seal type adhesive is applied are as follows, since it can be bonded without heating, it can be used as a packaging material for contents which are easily affected by heat. Since the adhesive strength is relatively low and the adhesive surface can be peeled off relatively easily, the low adhesive strength can be used as an easy-peeling adhesive as an advantage in opening. In the present invention, by controlling the amount of the organic filler to be added to the cold sealant, the adhesive strength (peeling strength) of the packaging material to which the obtained cold sealant is applied can be more easily adjusted. Was found. As the easy peeling property, a non-adhesive portion is provided outside the adhesive blocking, and the non-adhesive portion is pinched with a finger,
By 90 ° or 180 ° peeling, the peeling property of the packaging material by the cold sealant to which the organic filler of the present invention is added is desirably peelable with a small force as long as it is possible to peel the infant if it is an infant. In the 90 ° peel test, the peel resistance value is 20 to 1000 g / 15
By being adjustable in the range of mm width, the design for easy peeling became extremely easy. The easy peelability of the cold seal type adhesive depends on the base material on which the adhesive is applied, but in the case of a paper base, the peel resistance value indicating the desired easy peelability is 50 to 200 g / 15 mm width. Range.

In the addition of the inorganic filler according to the prior art, the possible range of mixing with the adhesive component is narrow, and the effect cannot be expected if the addition amount is small. Dispersion becomes difficult, and suitability in the coating process becomes extremely poor.

The packaging material to which the cold sealant has been applied and dried is often wound up into a roll and supplied to an automatic packaging machine for use. The packaging material coated with the cold sealant according to the related art may be unusable because the coated surface and the back surface are blocked during the roll-up and storage period during the storage. As a countermeasure, a release layer (release varnish) is provided on the back surface of the cold seal agent application surface to prevent blocking. Therefore, a separate process is required, and this is a factor of cost pressure. By adding an organic filler to the cold sealant of the present invention, the blocking layer was not provided, and when winding up, even if it was solid-wound compared to the case of the conventional technique, no blocking trouble occurred. . Winding up tightly,
Further, when the roll-shaped material coated with the cold seal agent is placed on the floor, the own weight of the roll-shaped material is partially pressurized,
Blocking occurs in the pressurized portion.

As described above, the cold sealant adheres by applying pressure while the application surfaces are brought into contact with each other, and does not adhere even when the application surface and the non-application surface are pressed. However, if storage conditions such as temperature and pressure are poor, the coated surface and the non-coated surface may be temporarily adhered to each other, which may hinder use.

Therefore, in order to prevent the blocking trouble, conventionally, when wound up in a roll shape, a release varnish has been applied to the surface where the cold sealing agent application surface is in contact, that is, the non-application surface. When the cold sealant of the present invention was applied, no blocking phenomenon was observed under normal storage conditions without applying a release varnish. In the roll-shaped material of the cold seal type packaging material of the present invention, the above-mentioned step of applying the release varnish could be omitted, so that the production cost was saved. In the present invention, it is not necessary to apply the release varnish as described above under normal conditions, but for safety, there is no problem even if the release varnish is applied.

[0018]

【Example】

<Preparation of Specimen> [Example] Kraft paper 40 g / m ² was used as a base material, and the following was used as a cold sealant. That is, as an adhesive component in the cold sealant, in each of Examples and Comparative Examples, natural rubber / acrylic resin was used.
D-HS1 (manufactured by The Inc.) was used.
As the organic filler, an acrylic filler having an average particle diameter of 8 μm, Techpolymer MBX-8 (trade name, manufactured by Sekisui Chemical Co., Ltd.) was added in the following amounts. Example 1 2% by weight Example 2 4% by weight Example 3 6% by weight The above-mentioned adhesive containing an organic filler was applied and dried to prepare a roll of a cold seal type packaging material, which was used as a test specimen. . (Dry coat amount 3g / m ² ± 0.2g /
m ² ] In addition, the cold seal agent is applied by a gravure method (the application roll uses a gravure plate with a plate depth of 35 μm) .After application, it is dried with hot air, and in each condition, it is rolled into a paper tube with a core inner diameter of 75 mmφ. 2000m was rolled in as normal winding hardness. [Comparative Example] Using 40 g / m ² of kraft paper as a base material, applying a cold sealant without adding an organic filler (the same as the cold sealant without adding an organic filler used in the examples), drying and applying a cold seal type A roll of the packaging material was prepared and used as a test body. [Dry coat amount
3g / m ² ± 0.2g / m ² ] In addition, the cold sealant is applied by gravure method (the application roll uses a gravure plate with a plate depth of 35μm). 2000 m was wound into a tube in a roll shape with a normal winding hardness. <Evaluation method> Evaluation method of blocking. The test specimens of Examples 1 to 3 and Comparative Example were directly placed on the floor (a) as shown in FIG. 3, a support rod was inserted into a paper tube, and the support rod was suspended on a stand. The test specimen was held under the conditions of 40 ° C. and 90% RH by two methods of hanging in the air (b) without applying its own weight. After 7 days, the presence or absence of blocking was checked while the roll of the test specimen was rewound. A method for measuring peel resistance. Using the test specimens used for the blocking test, the surfaces coated with the cold sealant were overlapped with each other, and were pressure-adhered under a pressure of 5 kg / cm ² in a room at 25 ° C. to form a test specimen having a width of 15 mm. Using Tensilon tensile tester,
Clamp both ends of each test piece and peel strength (90 °
Peeling) was measured. <Evaluation Results> The evaluation results of the blocking were as shown in Table 1. Table 2 shows the results of the measurement of the peel resistance.

[0019]

Conventionally, when a packaging material coated with a cold sealant is formed into a roll, the coated surface and the back surface may be blocked. However, the cold sealant according to the present invention may be used. As a result, the blocking phenomenon was eliminated, and the peeling resistance value of unsealing at the time of use was able to be adjusted, so that a cold-sealing packaging material that was stable even in the application step could be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view and a partially enlarged view of an embodiment of a packaging material coated with a cold sealant of the present invention.

FIG. 2 is a cross-sectional view of another embodiment of the packaging material coated with the cold seal agent of the present invention.

FIG. 3 is a perspective view showing an example of a method of storing a roll-shaped material of a cold seal type packaging material according to the present invention, wherein (a) is an example of direct mounting, and (b) is an example of hanging.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base material 2 cold sealant F organic filler 10 roll of cold seal type packaging material 11 paper tube 12 stand 13 support rod

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Watanabe 450 Aotomachi, Yokohama-shi, Kanagawa Prefecture The Inteck Co., Ltd.

Claims (2)

[Claims] 1. A packaging material in which a cold seal type adhesive which can be adhered by pressing at room temperature is applied to a base material, wherein said adhesive contains an organic filler having a particle size of 0.1 to 150 μm in an amount of 1 to 20 μm. A roll of cold seal type packaging material, characterized in that it is added by weight%. 2. The method according to claim 1, wherein the base material is paper.
A roll of the cold seal type packaging material described.