JP2640964B2 - Freshness retaining sheet, method for producing the same, and apparatus for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a freshness retaining sheet used for maintaining freshness of fresh foods and preventing dying of vegetables, fruits and flowers. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a freshness preserving sheet capable of maximizing the effect of freshness preserving power, a method of manufacturing the same, and a manufacturing apparatus thereof.

(Prior art)

Recently, in order to keep the freshness of vegetables and fruits during storage and transportation as much as possible, techniques for including or interposing a freshness preserving agent in packaging materials have been actively developed.

For example, the development of a plastic film kneaded with a freshness preservative, or between surface materials consisting of paper or non-woven fabric,
There is a type in which a powdery gas adsorbent or a moisture absorbent is sandwiched, and an acrylic or urethane emulsion adhesive, a thermoplastic resin powder or fiber such as polyethylene is used as a binder, and integrated.

Furthermore, between the surface materials made of paper or nonwoven fabric, a core material having a mixed layer of a powdery gas adsorbent and a superabsorbent polymer material on one surface of a cellulose fiber nonwoven mat is sandwiched, There is a freshness preserving sheet (Japanese Utility Model Publication No. Sho 62-19183) integrated by heating embossing.

As described above, the conventional freshness holding sheet is a sheet in which the freshness holding agent is held in layers between the upper and lower breathable sheets (surface material made of paper or nonwoven fabric, or a fibrous sheet, etc.). Although various types are used depending on the object and purpose of maintaining freshness, they are generally in the form of powder or granules.

In the conventional production of a freshness retaining sheet, a freshness retaining agent is sprayed on one of the air permeable sheets, the other air permeable sheet is coated thereon, and the upper and lower air permeable sheets are fixed to each other. However, since this lacks the adhesive stability to maintain the laminated form, apply or spray an adhesive on one of the breathable sheets and spray a freshness-retaining agent on it,
It has been practiced to cover the other breathable sheet thereon and integrate it by bonding.

[Problems to be solved by the invention]

However, in the conventional freshness maintaining sheet, since a binder is used, the surface of the gas adsorbent or the moisture absorbing agent is partially covered by the binder, and there is a disadvantage that the performance of maintaining the freshness is reduced.

In addition, paper or nonwoven fabric used as a surface material has poor moisture control performance. Further, even if powdery particles of a gas adsorbent or a water absorbing agent are evenly spread on the surface of paper or nonwoven fabric, the powdery particles move. It was also difficult to pinch uniformly.

On the other hand, storage of fresh food requires proper water absorption and proper moisture proof. That is, if fresh water dew condensation or the like due to respiratory action is left as it is, it easily causes spoilage due to propagation of various bacteria. However, excessive evaporation of water also causes a dehydration phenomenon, which causes a decrease in freshness such as atrophy.

In other words, for fresh food, water absorption that is sufficient to properly remove condensation due to respiratory action is optimal.

In this respect, the prior art disclosed in Japanese Utility Model Publication No. Sho 62-19183 was not satisfactory because an optimum water absorption and moisture prevention effect was not obtained.

In addition, since a mixed layer of a gas adsorbent and a superabsorbent polymer material is provided on one surface of a nonwoven cellulose fiber mat as a base, the production process is complicated and the cost is high.

Furthermore, the upper and lower breathable sheets in the prior art have a poor freshness and are easy to peel off due to the intermediary of an unstable freshness retaining agent between them. Of course, if a large amount of adhesive is used in order to improve the adhesiveness of the upper and lower breathable sheet, it will impregnate the freshness retaining agent as a whole,
There is a disadvantage that the effect of the freshness preserving agent is significantly reduced.

The present invention solves the drawbacks of the prior art, and has a suitable water-absorbing moisture-proof property to remove dew, and does not particularly use an adhesive that easily impregnates the freshness preserving agent, so that the front and back sheets are interposed therebetween. It is stably held across the freshness preservative,
Moreover, it is an object of the present invention to provide a freshness retaining sheet having a structure in which the effect of the freshness retaining agent is sufficiently exerted, and a simple production method and production apparatus therefor.

[Means for solving the problem]

In order to achieve the above object, the sheet of the present invention has a moisture-proof adhesive layer that also constitutes a moisture-proof layer, a powdery and granular freshness-maintaining agent adhered and fixed to the surface, and a water-absorbing layer is laminated on the surface of the freshness-maintaining agent. The gist of the invention is that the powdery and freshness retaining agent is sandwiched between the moisture-proof adhesive layer and the water-absorbing layer.

When the type of adhesive is classified according to its curing reaction, a solvent volatilization type (solidifies due to the volatilization of the solvent and develops an adhesive force. In this case, a chemical reaction generally does not accompany), a chemical reaction type (a chemical reaction Hardens and develops adhesive strength), hot-melt type (hot-melt type) (solid or film-like adhesive, applied by heating and melting, and solidifies when cooled to develop adhesive strength) Among them, the solvent evaporation type is divided into a solvent type and a water dispersion type (polyvinyl acetate emulsion), and the solution type is an organic solvent type (chloroprene rubber, urethane) and a water solvent type (starch, polyvinyl alcohol, water glass). ). Among these, the organic solvent type, the chemical reaction type (epoxy type, acrylic type, etc.) and the hot melt type (polyamide, polyester, polyolefin) of the solvent volatilization type are referred to as moisture-proof adhesives in the present invention. In particular, when the hot-melt resin is laminated on the substrate surface by the extrusion method, it functions as an adhesive until it is fixed and forms a film. It can be adopted as an effective moisture-proof adhesive.

Examples of the water-absorbing layer include kraft paper, glassine paper, Japanese paper, thin paper, tissue paper, cardboard cardboard, paperboard, various water-absorbing papers, Piropack, other nonwoven fabrics, cellophane, cloth, and the like.

Gas fresheners such as ethylene (Oya stone, coral, shells, activated carbon, carbon fiber, halogenated carbon, diatomaceous earth, acid clay, zeolite, etc.), antibacterial agents (zeolites), deodorants (Anico, activated carbon) And the like, a denaturation inhibitor 8 (for example, based on cristobalite), a freshness retaining agent for far infrared rays, and the like. These mixtures are used depending on the stored items, and the mixing ratio is appropriately set. This freshness retaining agent is in the form of a powder. Preferably, a powder having a size of 60 mesh or less is good.
The thickness of the layer is preferably about 0.2 to 2.5. In addition, it is also possible to adopt a configuration in which the presence of the freshness retaining agent is partially dispersed.

In addition, a corrugated cardboard structure can be formed by using the above sheet, and further, a box can be formed.

The first method of the present invention for producing the above-mentioned freshness-preserving Sino is as follows:
In the moisture-proof adhesive layer, first of all, a portion that functions as an adhesive is provided in a partially scattered manner, and a granular freshness retaining agent is adhered to the partially functioning adhesive layer. The gist of the present invention is to directly adhere a moisture-absorbing layer portion, which does not function as an adhesive layer but exclusively functions as a moisture-proof layer, to a water-absorbing layer.

In the second manufacturing method, a heat-welding resin layer is formed on the outer surface of the back sheet, and a portion of the heat-sealing resin layer where the air-permeable front sheet is partially adhered to the back sheet is removed. The gist of the present invention is to apply a powdery and granular freshness retaining agent to the melted portion by heating and melting the portion, and then partially bond the front sheet by heating and melting the remaining portion.

Further, a device for manufacturing a freshness maintaining sheet includes a partial pre-heater device capable of partially leaving an unfused portion in the heat-welding resin layer in a flow path of the back sheet having a heat-welding resin layer formed on an outer surface; An adhering device capable of passing the powder through the particles of the freshness retaining agent, a heating device for heating the entire surface toward the back sheet, and a pressing device for pressing the front sheet from the side where the heat-fusible resin layer is formed on the back sheet. Are arranged sequentially.

[Action]

According to the freshness preserving sheet of the present invention, the freshness preserving agent is not buried in the resin film or covered with the binder, and of course the fresh food is adjusted by adjusting the water absorbing layer and the moisture-proof adhesive layer. Modest water absorption and moderate moisture proofing are possible, and the prevention of dew condensation and the prevention of atrophy due to dehydration can be adjusted in a well-balanced manner, and the decrease in freshness can be delayed as much as possible.

Further, according to the above-described production method and production apparatus, the back sheet in which a heat-welding resin layer is formed in advance can be used. Because only the part where the agent adheres is heat-melted,
Simply by passing the powder through the powder, the adhesion to only the necessary portions is completed. In addition, the portion where the freshness retaining agent has not been attached can be melted by simple heating, and the front sheet can be partially adhered to the back sheet by simple pressing. A very stable laminated structure is obtained by partial adhesion of the back sheet to the front sheet, and since the heat-welding resin layer does not melt on the air-permeable front sheet side, the effect of the freshness preserving agent on that side is obtained. Is remarkably exhibited.

〔Example〕

 Hereinafter, embodiments will be described with reference to the drawings.

FIGS. 1 and 2 show an embodiment in which the sheet of the present invention is embodied in the form of a paperboard. FIG. Starch paste 6
It is glued. The moisture-proof layer 1 has a polyethylene heat-welding resin layer 7 between the freshness-maintaining agent 3 and the paper 8 as a moisture-proof adhesive layer.

FIG. 2 shows that the nonwoven fabric 9 is adhered to the freshness preserving agent layer 3 by the water-absorbing layer 2 and the ordinary starch paste 6, and the moisture-proof layer 1 is a polyethylene film layer 7. This polyethylene film 7 is heat-fusible, functions as a moisture-proof adhesive for the freshness-keeping agent, and is in a state of being directly bonded.

FIG. 3 is a diagram in which the paperboard-like sheet S is incorporated into a corrugated cardboard structure D. The example of the paperboard-like sheet S is the first or second paperboard-like sheet S.
Not only the example but also the following embodiments are included. Examples of the corrugated cardboard structure include double-sided, double-sided, and double-sided.

FIG. 4 shows the case in which the paperboard-like sheet S (FIGS. 1 and 2) or the corrugated cardboard sheet (FIG. 3) is used for the box H, and the box H may be formed from the sheet. Or at least one of the outer surface and the inner surface of the box H.
In particular, those stuck on the inner surface have a large freshness retaining effect. Or, for example, it may be partially applied to only the inner surface of the side wall (body portion), not to the entire surface. In this way, the cost can be saved and the effect of maintaining freshness can be sufficiently exhibited.

FIGS. 5 to 7 show another embodiment sheet, in which the freshness preserving agent 3 is not evenly interposed between the entire surface of the water-absorbing layer 2 and the moisture-proof layer 1 but is partially dispersed. At the same time, the back surface of the water-absorbing layer 2 was directly adhered or welded to the moisture-proof layer 1 at the portion where the freshness-retaining agent 3 was not interposed, and the freshness-retaining agent 3 was partially enclosed as if it were bound in a bag and scattered in a lattice. It is an Example group.

FIG. 5 shows that the water-absorbing layer 2 is made of kraft paper 2c, the moisture-proof layer 1 is made by applying a waterproof hot-melt adhesive layer 6c to the back surface of the paper 8, and the portions where the freshness preserving agent 3 is not interposed are The surface of the kraft paper 2c is adhered to the hot melt adhesive layer 6c forming the moisture proof layer 1 to form a direct bonding portion 4 between the water absorbing layer 2 and the moisture proof layer 1. The portion where the freshness retaining agent 3 is interposed is sealed and held in a bag shape by the water-absorbing layer 2 and the moisture-proof layer 1 to form a holding portion 5.

FIG. 6 shows an example in which the water-absorbing layer 2 is a nonwoven fabric 9 and the moisture-proof layer 1 is composed of the heat-meltable polyethylene film 7 alone which functions as a moisture-proof adhesive at the time of heat melting. The paper 2a, in which the moisture-proof layer 1 is formed by laminating a heat-fusible polyethylene film 7a on the back surface of the paper 2b, the polyethylene film 7a has the following relationship with the paper 2a of the water-absorbing layer 2:
In the embodiment, the adhesive portion 4 functions as a moisture-proof adhesive by utilizing its heat melting property.

Next, an embodiment of the manufacturing method and apparatus of the present invention will be described with reference to FIGS. 8 to 14.

The drawing shows one embodiment, and the freshness maintaining sheet P
As shown in FIG. 8 and FIG.
And a water-absorbing layer 2 on the front side, with a freshness-preserving agent 3 interposed therebetween, and the moisture-proof layer 1 and the water-absorbing layer 2 partially adhered by an even distribution. Therefore, the holding portion 5 of the freshness holding agent 3 is formed in a square or diamond shape. As members or materials, a backing sheet 1a forming the moisture-proof layer 1 is heat-fused, and in addition to a heat-bonded film 1b showing adhesiveness, a cover 2a forming the water-absorbing layer 2 is formed.
A powdery freshness retaining agent 3 is used.

FIG. 10 shows a device for manufacturing the freshness preserving sheet P, which comprises a partial preheater device 10, an adhering device 11, a heating device 12, and a pressure bonding device 13 of the freshness preserving example 3.

The partial preheater device 10 includes a heating roll 20 driven in accordance with the flow of the backing paper 1a and holding rolls 22 on both sides thereof. Is formed.

Then, as shown in FIG.
The backing paper 1a on which 1b is laminated is first fed into the partial pre-heater device 10, is joined to the outer peripheral surface of the heating roll 20 while being held by both holding rolls 22, 22, and is fed out. 1b melts and begins to function as a moisture barrier adhesive. However, since the joining portion is a portion other than the concave groove 21, as shown in FIG. 12, a fused portion 7a and an unfused portion 7b are generated in the heat welding film 1b.

Next, the back surface 1a is fed into the freshness retaining agent attaching device 11, which fills the box 25 with the granular freshness retaining agent 3, through which the back surface 1a passes. The freshness retaining agent 3 adheres to the fusion portion 7a of the heat-sealed film 1b during the heating. A main roll 26 and a pair of sub-rolls 27, 27 are formed.

The backing paper 1a fed out of the adhering device 11 passes over the heating device 12, and the unfused portion 7b of the hot-melt film 1b is melted by the heat received during the heating to form a new melted portion 7c (FIG. 13).

The heating device 12 is of a hot-air heating type in order to prevent the risk of fire that ignites the paper, and the heating temperature of the hot air is optimally around 270 ° C. However, it may be of a radiant heat type.

The backing paper 1a that has passed through the heating device 12 is fed together with the cover 2a between the upper and lower press rolls 30 and 31 in the next pressure bonding device 13. Then, the cover 2a is crimped to the lower surface of the backing 1a and adheres at the new fusion part 7c, and as shown in FIGS. 8, 9 and 14, the freshness is maintained between the backing 1a and the cover 2a. The agent 3 is sandwiched and held by pressure bonding, and a freshness maintaining sheet P having a stable laminated structure in which the back paper 1a and the cover 2a are partially adhered is obtained.

In the pressure bonding device 13, the cover 2a falls between the freshness preserving agents 3 and 3 and is adhered to the backing paper 1a by being attached thereto. However, the upper press roll 30 is changed to a hard iron large roll so as to easily reach the backing paper 1a. The lower press rolls 31 are formed as small elastic rolls made of rubber. Also, press roll on
30 is constantly heated to around 200 ° C. This allows backing paper 1
The cover 2a is firmly adhered to the a
And the aperture of the entire laminated form is good.

Since the freshness retaining sheet P is made of paper, it is suitable for use as a liner for corrugated cardboard, and it is easy to obtain packing materials such as corrugated cardboard and corrugated cardboard boxes suitable for maintaining freshness of fresh foods and the like.

Then, by connecting or incorporating the above-described manufacturing apparatus into a corrugating machine for manufacturing corrugated cardboard, freshness-preserving corrugated cardboard can be manufactured at a stroke.

[Other examples etc.]

In the embodiment of the manufacturing method and the manufacturing apparatus, the heat-sealing film 1b is used for attaching the freshness preserving agent 3 to the backing paper 1a, bonding the cover 2a, and further forming the moisture-proof layer 1. A waterproof hot-melt adhesive may be applied to or sprayed on the backing paper 1a.

A material other than paper can be used for the back paper 1a and the cover 2a, but the cover 2a needs to be a breathable sheet in order to exert the effect of the freshness retaining agent 3. The backing paper 1a may be either a breathable or non-breathable sheet. However, there is an advantage that it can be easily used as a cardboard liner depending on the paper quality of the backing paper 1a.

The partial pre-heater device 10 may have a structure in which a partial cooling roller follows a general heating roller having a smooth outer peripheral surface, unlike the above-described embodiment. Heating may be performed from either side of the backing paper 1a and the heat-sealing film 1b, and from the backing paper 1a side, temperature adjustment is easy,
A high temperature is required. Conversely, if the temperature is from the film 1b side, the temperature adjustment is severe and difficult, but a low temperature is sufficient.

〔The invention's effect〕

According to the sheet of the present invention, the freshness-retaining agent is sandwiched between the water-absorbing layer and the moisture-proof adhesive layer as the moisture-proof layer in the state of powder and granules. Effectively demonstrated.

That is, the moisture-proof adhesive layer exhibits a function as a moisture-proof layer and a function of bonding and holding the freshness-retaining agent in a powder state, and as a moisture-proof layer, prevents excessive evaporation of moisture of the contents, In addition to preventing atrophy of fresh foods, it also has a waterproof effect on a paperboard-like sheet or a corrugated cardboard sheet, and further on a box body, and can also play a role of ensuring stability of strength.

In addition, the water-absorbing layer prevents condensation on the surface of the sheet or the box body, prevents the freshness-retaining agent from falling off the moisture-proof layer, and secures air permeability to the freshness-retaining agent to give appropriate moisture. be able to.

In addition, if the sheet is configured such that the water-absorbing layer and the moisture-proof layer are directly adhered partially (for example, in a lattice shape) and the freshness-retaining agent is partially scattered and sealed, No adhesive layer is required between the water absorbing layer and the adhesive layer, and in this case, the performance of the freshness retaining agent can be more effectively exhibited. In addition, the material cost is reduced because the adhesive layer is unnecessary.

On the other hand, according to the manufacturing method and apparatus of the present invention, a hot-melt resin layer is formed on the outer surface of the back sheet, and the hot-melt resin is first melted except for the bonding portion of the front sheet, so that the melting point Since the freshness-retaining agent is attached to the backsheet, the next step is to melt the heat-sealable resin in areas other than where the freshness-retention agent is attached by simply radiating the heat toward the backsheet, and then press the front sheet only to apply the backsheet. Since it can be partially adhered to the sheet, it is extremely easy to manufacture a freshness retaining sheet, and there is no waste in the process, which is suitable for mass production.

In addition, as for the manufactured freshness retaining sheet, since the back sheet and the front sheet are bonded by partial adhesion, they do not peel off from each other, and hold a stable laminated form in which a freshness retaining agent is held therebetween. Moreover, there is almost no permeation into the freshness retaining agent due to the melting of the resin, and since the freshness retaining agent on the front sheet side having air permeability is safe, there is an excellent effect that the effect of the freshness retaining agent is easily exerted. .

[Brief description of the drawings]

FIG. 1 and FIG. 2 are cross-sectional views of each embodiment of the paperboard sheet of the embodiment sheet of the present invention. FIG. 3 is a cross-sectional view of another embodiment sheet in which the present invention is applied to a corrugated cardboard structure, and FIG. 4 is a perspective view of a box formed or including the embodiment sheet of the present invention. 5 to 7 are perspective views each showing a cross section of a main part of another embodiment sheet of the present invention. 8 to 14 show an embodiment of the manufacturing method and the manufacturing apparatus of the present invention. FIG. 8 is a perspective view of a freshness retaining sheet manufactured by the method and the apparatus, and FIG. 9 is FIG. A
FIG. 10 is an enlarged sectional view taken along the line A, FIG. 10 is a perspective view of the manufacturing apparatus,
11 to 14 show the BB line and CC line in FIG.
It is explanatory drawing by each expanded cross section of a line, DD line, and EE line. DESCRIPTION OF SYMBOLS 1 ... Moisture-proof layer, 2 ... Water absorption layer 3 ... Freshness retention agent, 4 ... Adhesion part 5 ... Retention part, 7b ... Unmelted part 10 ... Partial pre-heater device, 11 ... Adhesion device 12 ... … Heating device, 13 …… Crimping device

Claims (5)

(57) [Claims] 1. A powdery / granularity freshness-maintaining agent is adhered and fixed to the surface of a moisture-proof adhesive layer that also constitutes a moisture-proofing layer, and a water-absorbing layer is laminated on the surface of the freshness-maintaining agent to maintain the powdery / granular freshness. A freshness maintaining sheet comprising an agent interposed between a moisture-proof adhesive layer and a water-absorbing layer in a sandwich manner. 2. The freshness retaining sheet according to claim 1, wherein the moisture-proof adhesive layer is a heat-welding resin layer. 3. In the moisture-proof adhesive layer, firstly, a portion exhibiting the function as the adhesive is provided in a partially scattered manner, and the partially functioning adhesive layer is kept in a powdery and granular freshness. A method for producing a freshness preserving sheet, comprising bonding an agent and directly bonding a moisture-absorbing layer portion, which does not function as an adhesive layer but exclusively functions as a moisture-proof layer, to a water-absorbing layer. 4. A heat-sealable resin layer is formed on the outer surface of the back sheet, and a portion of the heat-sealable resin layer excluding a portion where the air-permeable front sheet is partially adhered to the back sheet is heated and melted. A method for producing a freshness-retaining sheet, characterized in that a powdery / granularity freshness-maintaining agent is attached to the melted portion, and then the remaining sheet is heated and melted to partially adhere the front sheet. 5. A partial pre-heater device capable of partially leaving an unmelted portion in a heat-sealable resin layer in a flow path of a back sheet having a heat-sealable resin layer formed on an outer surface thereof; An adhering device that can pass through the powder, a heating device that radiates heat entirely to the back sheet, and a pressure bonding device that presses the front sheet from the side where the heat-fusible resin layer is formed on the back sheet are sequentially arranged. An apparatus for manufacturing a freshness maintaining sheet.