JPH02232291A - Cold storage material and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a cold storage material and a method for manufacturing the same.

More specifically, the present invention relates to a cold storage material that can be suitably used for cold storage, freshness preservation of vegetables, medical purposes, etc., and a method for producing the same.

[Conventional technology] Conventionally, cold storage materials have been used such as those in which water or viscous liquids are sealed in metal cans or plastic cases, and those in which gel-like substances are sealed in bags made of hydrophobic film. . Among these cold storage materials, gel-like materials, especially hard gel-like materials, are easier to handle during freezing processing and maintain uniform cold inside the cold storage box than those using water or viscous liquids. desirable in that respect.

Therefore, in recent years, gel materials have been frequently used as cold storage materials, but according to the conventional manufacturing method of hard gel materials, it is necessary to increase the resin solid content concentration to 10% or more, and therefore the calorific value of the gel material has to be increased. Therefore, creating a hard gel-like material with a low resin concentration has become a major challenge.

In addition, conventional gel-like materials are packaged with a hydrophobic film to prevent water evaporation, but since gel-like materials do not adhere tightly to the film, gel-like materials are particularly large and thick. There is no gel-like material in the thin material.
There were 7 problems, including difficulty in handling. Therefore, as a method to improve the adhesion between the gel-like material and the film, a method has been adopted in which the gel-like material is placed in a bag-like film and the gel-like material is sealed in the bag-like film under reduced pressure. There is a drawback that when a bottle hole or the like occurs, the gel-like substance and the film separate.

[Problem WJ that the invention seeks to solve] Therefore, as a result of intensive research in view of the above-mentioned prior art, the present inventor discovered a hard gelatinized body with a low sap concentration. However, when using a packaging base material in which a water-impermeable thermoplastic resin layer is provided on one side of a non-woven fabric, and the non-woven fabric surface is placed in contact with a gelled body, it is surprisingly possible to They discovered for the first time that scales can achieve extremely good adhesion between a packaging base material and a gelled material, which had been thought to be impossible, and led to the completion of the present invention.

[Means for Solving the Problems] That is, the present invention provides a cold storage material consisting of (1) a packaging base material in which a water-impermeable thermoplastic resin layer is provided on one surface of a nonwoven fabric, and a gelled body; A cold storage material in which the surface of the packaging base material on which the nonwoven fabric is provided becomes the inner surface of the cold storage material, and the gelled body is adhered to nonwoven fabric; A mixture of polyvinyl alcohol and a super absorbent resin is placed in a bag body, which consists of a packaging base material provided on one side of the packaging base material, and the surface of the packaging base material where the non-woven fabric is provided becomes the inner surface. After filling the paste,
A method for producing a cold storage material, which is characterized by forming the bag into a desired shape and then subjecting the bag to freezing treatment; After filling a mixed paste of polyvinyl alcohol and a super absorbent resin together with a gelling agent into a bag body provided so that the surface on which the nonwoven fabric of the wrapping bag base material is provided becomes the inner surface, it is shaped into a desired shape. The present invention relates to a method for manufacturing a cold storage material, which comprises molding the bag into a bag body, and then subjecting the bag body to a freezing process.

[Function and Examples]

As described above, the cold storage material of the present invention is a cold storage material consisting of a packaging base material in which a water-impermeable thermoplastic resin layer is provided on one surface of a nonwoven fabric, and a gelled material, and the nonwoven fabric of the packaging base material is provided so that the surface provided with is the inner surface of the cold storage material,
In addition, the gelled body is mixed with a nonwoven fabric.

Since the cold storage material 1 of the present invention is made by bonding and integrating the gelled body and the nonwoven fabric, it is thin and has a size that can fit on the floor surface of storage containers for frozen and refrigerated foods. In addition, as with conventional cold storage materials, where the gelled body and sheet are temporarily left in a vacuum bag, the gelled body and sheet will peel off due to minute scratches on the sheet, and gelation will occur. Since there is no problem such as the sheet shifting on the body, it can be suitably used as a cold storage material for storage containers used to keep frozen and refrigerated foods uniformly cold.

The gelled product used in the present invention is mainly composed of polyvinyl alcohol, super absorbent resin, and water.

The polyvinyl alcohol has a saponification degree of 88%.
or more, and the average degree of polymerization is 1000 or more, preferably 1
400-2000, particularly preferably 1600-190
The one that is 0 is used. In the case where the degree of saponification is less than 88% or the degree of polymerization is less than 1000,
The gel strength tends to decrease, resulting in a so-called loose gelled body.

The polyvinyl alcohol may optionally contain natural products such as seaweed and vegetable mucilage; starch;
A cellulose-based semi-synthetic polymer compound; a synthetic polymer compound such as polyacrylamide, etc. may be blended as appropriate.

Examples of the superabsorbent resin used in the present invention include crosslinked polyacrylates such as crosslinked sodium polyacrylate, polyethylene oxide, polyvinyl pyrrolidone, sulfonated polyethylene, and starch-(meth)acrylonitrile copolymers. Examples include saponified products, starch-acrylic acid phosphorus polymers, polyacrylamide, vinyl ester-unsaturated carboxylic acid copolymers or their saponified products, vinyl ester-unsaturated carboxylic acid derivative copolymers or their saponified products, etc. These Takakura water-based resins may be used alone or in combination of two or more. Typical examples of unsaturated carboxylic acids used in the vinyl ester unsaturated carboxylic acid copolymer or its saponified product and the vinyl ester-unsaturated carboxylic acid derivative copolymer or its saponified product include acrylic acid, methacrylic acid, etc. , unsaturated monocarboxylic acids such as crotonic acid, or their esters or salts; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, or their partial or complete esters or salts; polyvinyl alcohol modified with anhydrides, etc. etc.

It should be noted that the present invention is not limited only to the examples of the superabsorbent resins mentioned above, and it goes without saying that other superabsorbent resins may be used within the scope of the present invention.

The blending ratio of the polyvinyl alcohol and super absorbent resin (
Polyvinyl alcohol/super absorbent resin double weight standard)
20/ 80 ~ 90/ 10, Nakanzu < 40/60
It is preferable that it is 70/30. If the blending ratio is smaller than 20/80, the adhesive strength between the resulting gelled product and the packaging base material will decrease;
If the weight exceeds this, the waist of the resulting gelled body will tend to weaken rapidly.

When obtaining the gelled product used in the present invention, water is blended in addition to the polyvinyl alcohol and super absorbent resin. Such water is not particularly limited in the present invention, and examples thereof include distilled water, pure water, etc., which are usually used to obtain a gelled product. The blending amount of the water is such that the content of the polyvinyl alcohol and super absorbent resin (hereinafter referred to as resin component) is 3 to 10% (weight %, the same applies hereinafter), preferably 5 to 10%.
Practically, it is desirable to adjust it to 8%. When the content of the resin component is less than 3%, it becomes difficult to maintain the shape of the resulting gelled product, and the gel strength tends to decrease, and when it exceeds 10%, the viscosity increases rapidly. , processability tends to decrease.

An example of a method for producing a mixed paste in which water is blended with the resin component is a method in which a polyvinyl alcohol solution of about 5 to 10% and a super absorbent resin containing the remaining water are mixed and kneaded. can give.

As a method for obtaining a gelled body from the mixed paste, (
-1') A method of gelling the iG mixture paste using a gelling agent, and a method of gelling the mixed paste by subjecting it to freezing treatment.

When obtaining a gelled product from the mixed paste by the method (a) above, the gelling agent may be, for example, boric acid,
It is preferable to use borax, glyoxal, ethylenediamine, etc., and mix the chemical in 1.0 to 20 parts with respect to 100 parts of polyvinyl alcohol (ffim part, hereinafter the same) and thoroughly knead the mixture.

In addition, when the gelled product is obtained from the mixed paste by the method described above, for example, the mixed paste may be mixed with -
It is preferable to cool and freeze at 10°C or lower, preferably <-20 to 30°C, and then thaw. In addition, when obtaining a gelled product by this method, for example, diamine,
When a mixed paste is cross-linked using dialdehydes or the like to obtain a gelled body, and this gelled body is subjected to freezing treatment, a gelled body with even greater hardness can be obtained. The gelled product thus obtained can be suitably used particularly in applications where mechanical strength is required.

In addition, the gel strength of the gelled product can be improved by repeatedly subjecting the obtained gelled product to the above-mentioned freezing treatment or by performing vacuum drying treatment during freezing to remove a small amount of water from the gelled product. Good too.

The gelled product obtained as described above is stored in a bag made of a packaging base material with a nonwoven fabric layer on the inner surface.In order to increase the adhesive strength between the gelled product and the nonwoven fabric, the bag is After putting the mixed paste 1 into the body, it is preferable to gel the mixed paste according to the method for obtaining a gelled body from the mixed paste.

In addition, in order to obtain a cold storage material having a desired shape, the bag containing the mixed paste may be rolled out flat using a roll with a smooth surface, or the surface may be shaped using an embossing roll or the like. It is also possible to provide unevenness.

In the present invention, the packaging base material used is one in which a water-impermeable thermoplastic resin layer is provided on one surface of a nonwoven fabric.

Examples of the thermoplastic resin used in the water-impermeable thermoplastic resin layer include polyolefin resins such as polyethylene and polypropylene, and polyamide resins such as nylon. The thickness of the thermoplastic resin layer varies depending on the use of the obtained cold storage material, but it is preferably about 20 to 50 m in consideration of mechanical strength as a packaging base material. The method of providing the thermoplastic resin layer on the nonwoven fabric includes, for example, a method of providing the thermoplastic resin layer by heating and melting the thermoplastic resin and coating or casting it on one surface of the nonwoven fabric; Examples of methods include forming a film in advance, laminating such a film on one side of a nonwoven fabric, and bonding and integrating it by heating or using a binder to form a thermoplastic resin layer. It is not limited only to the method.

Examples of the nonwoven fabric include spunbond nonwoven fabric, needle punch nonwoven fabric, etc. Among these nonwoven fabrics, 21 dollar punch nonwoven fabric in particular intertwines with the gelled material and becomes integrated, and the peel strength between the gelled material and the nonwoven fabric is high. This is preferable because it becomes larger. Examples of the fibers used in the nonwoven fabric include polyester fibers, polyethylene fibers, polypropylene fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, polyamide fibers, ethylene-vinyl acetate fibers, rayon fibers, acetate fibers, cotton,
Examples include wool, and these fibers may be used alone or in combination of two or more. In addition, in the case where the packaging base material is used as a bag, a gelled material is placed inside the bag, and the opening is sealed by heating, for example, among the fibers, polyolefin resin fibers and polyamides that melt when heated are used. It is preferable that at least one type of resin fiber is contained as a main component. The basis weight of the above-mentioned nonwoven fabric cannot be determined unconditionally because it varies depending on the purpose of the cold storage material obtained, but it is usually 5 to 100 g/r++F.
, it is preferable that the content is <20 to 60 g/i.

In addition, in general, in a case using a cold storage material, the cold storage temperature and the cold storage time are determined by the shape of the cold storage material, ffiffi, etc.; A resin layer in which aluminum is vapor-deposited may be provided, or aluminum powder may be kneaded into the thermoplastic resin layer to block only radiant heat.

As mentioned above, in the cold storage material of the present invention, the gelled body is bonded and integrated with the nonwoven fabric of the packaging base material, and the cold energy of the gelled body is directly transferred to the thermoplastic resin layer that is the outer skin of the cold storage material. It has excellent heat transfer efficiency.

Note that the shape and size of the cold storage material of the present invention are arbitrary and may be adjusted appropriately depending on the application, but for example, when the cold storage material of the present invention is used by freezing in a home freezer It is preferable to perform freezing treatment in a short period of time without taking up as much space as possible. For example, as shown in Figure 1, the mixed paste is placed in the packaging base material (1) and the opening (2) is sealed. It is preferable to use a cold storage material in which the packaging base material and the gelled body are integrated by forming the package into an uneven shape and then subjecting the mixed paste to a gelling treatment.

In this case, the opening (2) of the packaging base material is closed by the gelled material, which acts as an adhesive, so there is no need to perform heat sealing or suturing. There are advantages.

Next, the cold storage shrine of the present invention will be explained based on the drawings.

FIG. 2 is a partially cutaway perspective view of the cold storage material of the present invention. In FIG. 2, a nonwoven fabric (4) is provided on the inner surface of a packaging base material (1) whose outer surface is provided with a thermoplastic resin layer (3). When the mixed paste is placed in the packaging base material (1), a portion of the mixed paste is impregnated into the nonwoven fabric (4). When the mixed paste is subjected to gelling treatment in this state, the mixed paste becomes a gelled body (6), which is firmly bonded to the nonwoven fabric (4), and at the same time, the raised part of the nonwoven fabric (4) is bonded to the gelled body (6). A bonding layer (5) with the gelled material (6) is formed, and the bond between the packaging base material (1) and the gelled material (6) becomes even stronger. Although the shape of the cold storage material shown in FIG.
It is appropriately selected from a range of about 0 degrees depending on the application.

Next, the cold storage material of the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

Example 1 and Comparative Examples 1 and 2 Polyvinyl alcohol (saponification degree 98%, polymerization degree 180
To 600 parts of a 7% aqueous solution of 0), 20 parts of crosslinked sodium polyacrylate containing 400 parts of water was added, and to this was added 1 part of a fungicide (Biocide 1800, manufactured by Taisho Corporation, trade name) and a stabilizer. Then, 1 part of EDTA-2Na was further added and kneaded for about 10 minutes to obtain a sticky and soft cake-like mixed paste.

60% polyester fiber and 40% polyethylene fiber
Needle-punched nonwoven fabric (tsubom 50g/rr?)
A packaging base material was obtained by applying polyethylene to a thickness of 50 mm on one side.

The obtained packaging base material is folded in half so that the nonwoven fabric side becomes the inner surface, and the ends are heat welded to form a bag with one end open (vertical 3
30mm, width 280mm).

The mixed paste was put into the obtained bag, and the mixed paste was adjusted to have a thickness of 13a++e and a weight of 1 kg, and then the opening of the bag was closed. Next, this bag was left in a freezer (room temperature -25°C) for 24 hours, and then taken out from the freezer to obtain a cold storage material. The obtained cold storage material was placed in a 201-volume expanded polystyrene container used for distributing perishable products, and its cold storage performance was examined in the following manner. The results are shown in Table 1.

For reference, the cold storage performance was investigated in the same manner as above using a commercially available product. The results are shown in Table 1.

(Cold retention performance) Commercially available konnyaku (temperature: 5
℃) in the center of the foamed polystyrene container (
Settings were made so that the temperature of X) and the temperature of the bottom part (Y) were measured. Next, a cold storage material (-20° C.) was placed on top of the konjac, and the violet in the container was placed on top of the konjac and left in a constant temperature room with an ambient temperature of 30° C., and changes in the temperature inside the container over time were examined.

In addition, the commercially available cold insulation materials used for comparison were cold insulation material A (14QX 18QX 22+am, 500
(use 2 pieces of g), cold insulation material B (80X 130
8 22mm steel (5 pieces weighing 200g) were used.

Example 2 A rice cake-like mixed paste was prepared in the same manner as in Example 1: Aa2, and placed in a bag (length: 330 mm, width: 80 mm) with one end open, which was obtained in the same manner as in Example 1. After adjusting the mixed paste to have a thickness of 5+am1 and a weight of 500 g, the opening of the bag was closed. Next, this bag was left in a freezer (room temperature -25°C) for 24 hours, and then removed from the freezer to obtain a cold storage material.

Two of the resulting cold storage materials were prepared, and their cold storage performance was examined in the same manner as in Example 1, except that they were each placed on the top and bottom surfaces of a 20 g expanded polystyrene container. The result is the first
Shown in the table.

[Margin below] From the results shown in Table 1, it can be seen that the cold storage material of the present invention obtained in Example 1 has better cold storage performance than the conventional products used in Comparative Examples 1 and 2.

Furthermore, as is clear from comparing Example 1 and Example 2, in the case where the cold insulating material was installed on the top and bottom surfaces of the expanded polystyrene container to match the inner surface of the container, the heavy melons of the cold insulating material were the same. However, it is clear that the temperature inside the container can be maintained at a lower temperature for a longer period of time.

However. Therefore, it is desirable that the cold insulating material be able to cover the inner surface of the container as much as possible, but since the cold insulating material of the present invention can be formed into a sheet shape as described above, these It can be seen that it can be used suitably for various purposes.

Examples 3 to 7 In order to investigate the relationship between resin concentration and stiffness of the gelled product, a mixed paste having the composition shown in Table 1 was prepared, and 1 kg of the mixed paste was coated with a polyethylene layer (thickness: 50 mm).爛）
A bag body consisting of a packaging base material provided on one side of a needle-punched nonwoven fabric (tsubo Q50g/nf) made of polyester fiber, and the nonwoven fabric side is the inner surface (
280 x 330 am) and subjected to freezing treatment in the same manner as in Example 1 to produce a cold storage material.

The obtained cold storage material was hung down from the edge of the desk, and the vertical length of the cold storage material hanging down at the bottom was measured, and this was evaluated as the stiffness of the gelled body. The results are shown in Table 2.

As is clear from the results shown in Table 2 in the margin below E, it can be seen that when the resin component concentration in the gelled body of the cold storage material exceeds 4%, the stiffness of the cold storage material decreases rapidly.

Example 8 and Comparative Examples 3 to 5 The concentration of the resin component was adjusted to 6% and the concentration of the super absorbent resin in the resin component was adjusted to 40%, and the materials shown in Table 3 were used as packaging base materials. A cold storage material was produced in the same manner as in Examples 3 to 7 except for the above. As a physical property of the obtained cold storage material, the degree of sagging was measured in the same manner as in Examples 3 to 7. The results are shown in Table 3.

[Margins below] Examples 9 to 11 Gelled products were obtained by using borax or dialdehyde for gelling polyvinyl alcohol, or by performing freezing treatment in the same manner as in Example 1.

The degree of sagging of the obtained gelled product was examined in the same manner as in Examples 3-7. The results are shown in Table 4.

Table 4 shows non-woven fabric made of polyester fibers (tsubom 50g/rf) provided with a polyethylene layer (thickness 50cm) or polyethylene film (thickness 30ρ) and nylon-6.
. , 6 films (thickness: 15 mm) were put into a bag (280 x 180+ am) and stretched smoothly, and then subjected to freezing treatment in the same manner as in Example 1 to obtain a cold storage material.

Examples 3 to 7 show the degree of sagging as the physical property of the obtained cold storage material.
It was measured in the same manner. The results are shown in Table 5.

[Margin below] Examples 12 to 15 and Comparative Examples 6 to 9 Gelled product of 6% resin concentration and 40% super absorbent resin based on the resin component 1 kg, 500 g, 300 g or 10
From the results shown in Table 5, it can be seen that as the thickness of the gelled body increases, the change in the degree of sagging due to the difference in the type of packaging base material becomes smaller.

In addition, in the cold storage materials of Comparative Examples 6 to 9, in which the gelled body and the packaging base material are not essentially bonded, the gelled body moves within the packaging base material and is unstable, making it completely unsuitable for practical use. It was something that didn't exist.

Practical example IB-21 A bag of 1 kg (28
Prototype 0 x 33 (lIII1) and 5 each
The materials were stacked in stages and left in a freezer at a room temperature of -25°C, and the time required for the third stage from the top to completely freeze was measured. The results are shown in Table 6.

[Margins below] [Effects of the Invention] The cold storage material of the present invention is characterized in that the gelled product obtained by gelling a mixed paste of a super absorbent resin and polyvinyl alcohol is a packaging base material consisting of a nonwoven fabric and a thermoplastic resin layer. Since the surface of the nonwoven fabric is firmly bonded, it can be suitably used as a thin sheet-like product, for example.

In addition, according to the manufacturing method of the present invention, a mixed paste having an appropriate viscosity is adhered to the surface of the nonwoven fabric, and then pressed using, for example, a mold roll or template, and formed into a rod shape, mat shape, or base shape. The gelled foam has the effect of being able to easily pass through cold storage materials of various shapes without losing its shape.

Furthermore, the cold storage material of the present invention is easy to handle, exhibits uniform cooling performance, and has a large heat storage capacity, and does not cause leakage even if the packaging base material is torn. Since there is no risk of contamination or the like, it can be suitably used for cold storage, for preserving the freshness of vegetables, for medical purposes, and the like.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a cold storage material of the present invention, FIGS. 2 to 6 are partially cutaway perspective views of a cold storage material of the present invention, FIG. 7 is a perspective view of a cold storage material of the present invention, and FIG. 8 is a perspective view of a cold storage material of the present invention. FIG. 2 is a partially cutaway perspective view of a cold storage material. (Main symbols in the drawings) (1): Packaging base material (3): Thermoplastic resin layer (4): Nonwoven fabric (6): Gelled body O2RO patent applicant Hiroshi Nakamura

Claims (1)

[Scope of Claims] 1. A cold storage material consisting of a packaging base material having a water-impermeable thermoplastic resin layer provided on one surface of a nonwoven fabric and a gelled body, wherein the nonwoven fabric of the packaging base material is provided with a gelled material. A cold storage material in which the gelled body is bonded to a nonwoven fabric, and the gelled body is bonded to a nonwoven fabric. 2. The cool storage material according to claim 1, wherein the water-impermeable thermoplastic resin layer is a polyolefin resin layer, a polyamide resin layer, or a composite layer of these resin layers. 3. The cold storage material according to claim 1, wherein the nonwoven fabric contains at least one of polyolefin resin fibers and polyamide resin fibers. 4. The cool storage material according to claim 1, wherein the gelled body is a mixed paste of polyvinyl alcohol and super absorbent resin. 5 The gelled product is obtained by mixing polyvinyl alcohol and super absorbent resin in a weight ratio of 20/80 to 90/10, and then gelling the mixed paste with a gelling agent or gelling it with a freezing treatment. The cold storage material according to claim 1, which is a cold storage material. 6. A bag consisting of a packaging base material with a water-impermeable thermoplastic resin layer provided on one side of a non-woven fabric, and the packaging base material provided with the non-woven fabric layer as the inner surface. A method for producing a cold storage material, which comprises filling the bag with a mixed paste of polyvinyl alcohol and super absorbent resin, molding it into a desired shape, and then subjecting the bag to freezing treatment. 7. A bag consisting of a packaging base material with a water-impermeable thermoplastic resin layer provided on one side of a nonwoven fabric, and the packaging base material provided with the nonwoven fabric on the inside surface. A method for producing a cold storage material, which comprises filling a mixed paste of polyvinyl alcohol and a super absorbent resin together with a gelling agent, molding the bag into a desired shape, and then subjecting the bag to freezing treatment.