JPH086080Y2 - Water absorbent sheet for food packaging - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a water absorbent sheet for food packaging having waterproofness, and more specifically, it is made of a highly water-absorbing polymer material and a water-permeable material. The present invention relates to an improved water-absorbent sheet for food packaging, in which the water-absorbent sheet is sandwiched and integrated with a material having a water-repellent property to impart waterproofness to a conventional water-absorbent sheet.

[Conventional technology]

Conventionally, water absorbent sheets have been used in various fields. In particular, it has been widely used in the fields of food drip absorbents, dew condensation water absorbents for fruits and vegetables, sanitary materials such as diapers, etc. It is being actively developed, and many high-quality water-absorbent sheets using new materials are being developed. [Problems to be solved by the invention] By the way, in these conventional techniques, since the water-absorbent sheet does not have a waterproof property, when actually used, the absorbed water permeates to the back surface of the sheet, which is inconvenient for use. There was a problem that caused.

That is, for example, when it is used for drip absorption of food, the drip oozes out to the back surface of the sheet, which is unsanitary and unsightly.

Further, when it is used for absorbing condensed water of fruits and vegetables, the absorbed water may penetrate to the back surface of the sheet, which may cause a decrease in strength of the absorption box for fruits and vegetables, that is, cardboard.

As described above, the conventional water-absorbing sheet has been developed as an excellent product in terms of material, but since it focuses only on the water-absorbing performance, it often causes inconvenience during actual use. There was a strong demand for the development of a new water-absorbing sheet that has both performance and waterproof performance.

As one method for solving the inconvenience, for example,
As disclosed in Japanese Laid-Open Patent Publication No. 52-31113, a highly water-absorbent polymer material is used between a front sheet made of a water-absorbent material such as paper and a non-woven fabric and a back sheet made of a water-resistant material such as a water-repellent thin film. It is known that the body secretions absorbed by the above are prevented from permeating to the outer surface of the back sheet.

However, a water-absorbent sheet in which this type of superabsorbent polymer material is enclosed between the front and back sheets is generally bulky and the encapsulated superabsorbent polymer material moves in the internal space of the sheet, resulting in uneven distribution. Has the inconvenience.

Therefore, when used for absorbing water in a relatively limited range such as absorption of body secretions, no particular problem occurs, but it has a wide absorption area such as drip absorption of food and dew condensation of fruits and vegetables. If such a water-absorbent sheet is used in an application requiring the water-absorbing sheet, the superabsorbent polymer material may not be uniformly distributed in the inner space of the sheet, so that the purpose as the water-absorbing sheet is not sufficiently fulfilled. There was a case.

[Means for solving the problem]

Therefore, the inventors of the present invention have conducted intensive studies with the aim of solving the problems of the conventional water-absorbent sheet, and as a result, have made a highly water-absorbent polymer material waterproof and water-permeable. By sandwiching and integrating between the materials with the heat-pressurization heating sandwiching means in a state where the surface is embossed, it becomes possible to impart waterproofness to the conventional water-absorbent sheet, and the absorbed moisture is absorbed. It is possible to prevent the permeation to the back surface of the sheet, and at the same time, find out that the enclosed superabsorbent polymer material is compressed and becomes flat as a whole, and its internal movement is restricted so that a uniform distribution state can be maintained. The present invention has been completed.

That is, the water-absorbent sheet for food packaging having waterproofness according to the present invention is provided on the surface of the highly water-absorbent polymer material between the material having at least water permeability and the material having waterproofing property by the heat-pressurizing / heating sandwiching means. Nonwoven fabrics are arranged on both front and back surfaces of a flat laminated body that is sandwiched and integrated in an embossed state, and the entire surface of the nonwoven fabric is embossed by the heat and pressure heating sandwiching means. It is characterized by being sandwiched and integrated.

[Action]

In the water absorbent sheet for food packaging having waterproofness according to the present invention having the above-mentioned configuration, the laminate as the base material is made of the super absorbent polymer material which is the water absorbing agent and is waterproof with at least the material having water permeability. It is formed by sandwiching and integrating the material with the surface being embossed by the heat, pressure and heating sandwiching means to prevent the absorbed water from permeating to the back surface of the sheet and to flatten it as a whole. And is formed without the flatness of the adsorbent.

Then, the nonwoven fabric is arranged on both front and back surfaces of the laminate, and the whole surface is sandwiched and integrated in a flat state with the surface of the nonwoven fabric being embossed by the heat-pressure heating sandwiching means. By forming the water absorbent sheet for use as a water absorbent sheet, uneven distribution of the highly water-absorbent polymer material, which is a water absorbing agent, is further corrected and evenly distributed, and it is also possible to avoid uneven distribution due to movement during use.

In addition, since the non-woven fabric is arranged on the front surface or the back surface that comes into contact with the food product to be packaged, the strength is higher than that when the outermost layer is paper, and the packaging material comes into contact with the food product. The risk of breakage and scattering of the superabsorbent polymer material inside is avoided. Further, since it is a non-woven fabric, it has a necessary cushioning property for food and a good feel to the hand, and the commercial value as a water-absorbent sheet for food packaging having waterproof property is remarkably improved.

〔Example〕

Hereinafter, the water absorbent sheet for food packaging having waterproofness according to the present invention will be described in more detail with reference to Examples.

FIG. 1 is a sectional view showing an embodiment of the present invention, in which a highly water-absorbent polymer material 3 is sandwiched between a paper 2 which is a water-permeable material and a resin-coated paper 4 which is a waterproof material, and The laminated body as a base material in which the paper 8 is laminated on the back surface of the resin-coated paper 4 is used as the nonwoven fabric 1 on the front surface side and the nonwoven fabric 5 on the back surface side.
It is sandwiched between. The material having water permeability is arbitrary as long as it has water permeability, and the material having water resistance is also arbitrary as long as it has water resistance.

Nonwoven fabrics 1 and 5 are thermoplastic resin non-woven fabrics partially or wholly, for example, non-woven fabrics in which fibers such as rayon and pulp are impregnated or mixed with resins such as polyolefin, polyester and polyamide, or polyolefin, polyester and polyamide. A non-woven fabric made of fibers such as the above is used, and one having a basis weight of 15 to 100 g / m ² is preferable.

As the paper 2 and the paper 8, soft paper having a basis weight of 10 to 60 g / m ² can be used. The resin-coated paper 4 is made of soft paper or the like having a basis weight of 10 to 60 g / m ^{2 on} which polyolefin, polyester,
A thermoplastic resin 7 such as polyamide coated with a thickness of 5 to 50 μ can be used.

The super absorbent polymer material 3 used in the present invention is a graft polymer of starch / acrylic acid salt, a crosslinked carboxymethyl cellulose, a vinyl alcohol / acrylic acid salt copolymer, a polyacrylonitrile hydrolyzate, a crosslinked polyacryl. Examples thereof include resins having high water absorption such as acid salts, modified polyvinyl alcohol, acrylate polymers, acrylate / acrylamide copolymers or isobutylene / maleic anhydride copolymers. It is also possible to use two or more of the above superabsorbent polymer materials. The amount of the super absorbent polymer material is preferably within a range of 0.1 to 50 g per 1 m ² of the sheet.

As a binder for sandwiching the highly water-absorbent polymer material 3 between the paper 2 and the resin-coated paper 4, a thermoplastic resin such as polyolefin, polyester or polyamide can be used. Since the plastic resin 7 is coated, it is of course possible not to use a binder.

Needless to say, various functionalities can be imparted by sandwiching a mixture of various functional materials and the superabsorbent polymer material instead of the superabsorbent polymer material alone.

The water absorbent sheet for food packaging having waterproofness according to the present invention is manufactured as follows.

A mixture of the highly water-absorbent polymer material 3 and the binder is evenly dispersed on the resin-coated paper 4, and the paper 2 is placed on the upper and lower sides thereof.
Then, the paper 8 is superposed, and the laminated body is manufactured by sandwiching and integrating the sheet by any one of the heat-pressure heating and sandwiching methods described later. Each layer of the manufactured laminate is sandwiched and integrated with the surface being embossed. It is cut into a certain size, put into a pouch (not shown) made of a non-woven fabric, and sandwiched and integrated by any of the heat-pressure heating sandwiching methods described later. As a result, non-woven fabric 1 on both front and back sides,
A water-absorbent sheet for food packaging in which 5 is arranged is obtained. In the manufactured water-absorbent sheet for food packaging, all layers are flatly sandwiched and integrated in a state where the surface is embossed.

A mixture of the highly water-absorbent polymer material 3 and the binder is evenly dispersed on the resin-coated paper 4, and the paper 2 is placed on the upper and lower sides thereof.
Then, the paper 8 is superposed, and the laminated body is manufactured by sandwiching and integrating the sheet by any one of the heat-pressure heating and sandwiching methods described later. Each layer of the manufactured laminate is sandwiched and integrated with the surface being embossed. Nonwoven fabrics 1 and 5 are superposed on both front and back surfaces of the manufactured laminate, and are sandwiched and integrated by any one of the heat-pressure heating sandwiching methods described below to produce a laminate. The surface of the manufactured laminated body is sandwiched and integrated in an embossed state. In the manufactured water-absorbent sheet for food packaging, all layers are flatly sandwiched and integrated in a state where the surface is embossed. Cut it to a certain size.

A mixture of the highly water-absorbent polymer material 3 and the binder is evenly dispersed on the resin-coated paper 4, and the paper 2 is placed on the upper and lower sides thereof.
And paper 8 are overlapped, and after sandwiching and integrating by any one of the heat-pressure heating and sandwiching methods described later, they are cut to a certain size, and non-woven fabric 1 and non-woven fabric 5 are superposed on both front and back sides thereof, and a side portion and an end portion. After being sealed, it is sandwiched and integrated by any one of the heat-pressure heating sandwiching methods described below to produce a water-absorbent sheet for food packaging. In the manufactured water-absorbent sheet for food packaging, all layers are flatly sandwiched and integrated in a state where the surface is embossed. Cut it to a certain size.

In addition, as the above-mentioned hot-pressurizing heating sandwiching method, the following methods (a) to (c) using a heating embossing roll can be mentioned.

(A) Between the heating embossing roll and the heating embossing roll (b) Between the heating embossing roll and the heating roll (c) Between the heating embossing roll and the roll As a result, the superabsorbent polymer material that is flat and sealed as a whole is inside Movement is restricted and a uniform distribution can be maintained.

Hereinafter, the present invention will be described in more detail with reference to examples according to the present invention.

[Example]

Practical example 1 ² pieces of super absorbent polymer material (AquaKeep 10SHP manufactured by Steel Manufacturing Co., Ltd.) on 25 g / m ² basis weight paper (MSP25 manufactured by Metel).
0g / m ² , binder (Toray Chemit R272S) 1g / m ²
Evenly dispersed, sandwiched between resin-coated paper (35 g / m ² paper with extrusion-coated polyethylene at a thickness of 30 μm), and the basis weight of 25 g / m ^{2 on} top of the resin-coated paper.
The paper was fed and passed through a heating embossing roll to be sandwiched and integrated.

The above base paper was cut into 320 × 210 mm, placed on a non-woven fabric (NA240JP2096 manufactured by Kuraray Co., Ltd.), and the lower non-woven fabric was folded into the side of the base paper. Further, the nonwoven fabric was fed from the upper part, and the side part was heat-sealed with a gear roll. The end portion was heat-sealed with a seal bar, and the whole was passed through a heating embossing roll to be sandwiched and integrated. After integration,
A water absorbing sheet was manufactured by cutting the end portion to 330 × 210 mm.

Comparative Example 1 ² pieces of superabsorbent polymer material (Aquakeep 10SHP manufactured by Iron and Steel Chemical Co., Ltd.) were placed on a paper (MSP25 manufactured by Metel Co., Ltd.) having a basis weight of 25 g / m 2.
0g / m ² , binder (Toray Chemit R272S) 1g / m ²
Was uniformly sprayed, sandwiched between papers with a basis weight of 35g / m ² , papers with a basis weight of 25g / m ² were fed, passed through a heating embossing roll, and integrated by sandwiching.

The above base paper was cut into 320 × 210 mm, placed on a non-woven fabric (NA240JP2096 manufactured by Kuraray Co., Ltd.), and the lower non-woven fabric was folded into the side of the base paper. Further, the nonwoven fabric was fed from the upper part, and the side part was heat-sealed with a gear roll. The end portion was heat-sealed with a seal bar, and the whole was passed through a heating embossing roll to be sandwiched and integrated. After integration,
A water absorbing sheet was manufactured by cutting the end portion to 330 × 210 mm.

[Experimental example]

The water absorbing sheet produced as described above was placed on white paper, and 200 ml of water colored with blue ink was absorbed. After standing for a certain period of time, the water absorbing sheet was peeled off and the degree of coloring under the water absorbing sheet was judged. The results are shown in Table 1.

As is clear from Table 1, it was confirmed that the use of the water absorbing sheet having the preventive property of the present invention can completely prevent the absorbed water from permeating to the back surface.

[Effect of device]

The water-absorbent sheet for food packaging of the present invention comprises a highly water-absorbent polymer material between a water-permeable material and a waterproof material,
Nonwoven fabrics are arranged on both front and back surfaces of the laminated body which is sandwiched and integrated by the heat and pressure heating and sandwiching means, and the surface of the nonwoven fabric is embossed by the heat and pressure and heating sandwiching means. Since the whole is sandwiched and integrated in the state where the water is applied, it is possible to completely prevent the moisture absorbed in the actual use from permeating to the back surface of the water absorbing sheet. There is an effect that the problem of the water absorbent sheet can be solved by a simple means and the added value of the water absorbent sheet can be further enhanced.

In addition, since the super absorbent polymer material is integrated twice by heating and pressurizing with a heating empos roll, it becomes flat as a whole with the super absorbent polymer material prevented from moving. Is advantageous in that it is simple and has a wide range of applications, and the industrial use value of the water-absorbent sheet is extremely high.

In addition, since the non-woven fabric is placed on the front or back surface that comes into contact with the food that is the product to be packaged, the strength is greater than when the outermost layer is paper, and during contact with food during transportation. Since there is no risk of the packaging material being damaged and the superabsorbent polymer material inside jumping out, safe food transportation becomes possible.

Further, since the front and back surfaces are made of non-woven fabric, it has a necessary cushioning property for food and a good feel to the hand, and the commercial value as a waterproof water-absorbent sheet for food packaging is significantly improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a water-absorbent sheet having a preventive property, which is one embodiment of the present invention. 1 ... Nonwoven fabric 2 ... Paper (water-permeable material) 3 ... Super absorbent polymer material 4 ... Resin coated paper (waterproof material) 5 ... Nonwoven fabric 6 ... Paper 7 ... Thermoplastic Resin 8: Paper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References 60-604603 (JP, U) 58-101737 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A superabsorbent polymer material is sandwiched and integrated between at least a water-permeable material and a waterproof material by a heat-pressure heating sandwiching means with the surface being embossed. Non-woven fabrics are arranged on both front and back surfaces of the flattened laminated body, and the entire surface is sandwiched and integrated in a state where the surface of the non-woven fabric is embossed by the heat-pressure heating sandwiching means. A water-absorbent sheet for food packaging that has flat waterproofness as a whole.