JPH02501379A - Absorbent structures for packaging - Google Patents

Abstract

The invention relates to the packaging field and the extended duration packaging of food products, particularly by modifying their environing atmosphere by means of an absorbing structure containing hydroreactive products. The structure of the invention absorbs liquids, exsudates or condensates, and generates an active element by reaction of the agent with the liquid. It is characterized in that it is comprised of at least one matrix formed, by aeraulic process, of a substantially fibrous mixture of hydrophilic and hydrophobic materials wherein said hydroreactive agent is distributed.

Description

[Detailed description of the invention] Absorbent structures for packaging The present invention relates to the field of packaging and its purpose is in particular to water-reactive ( surrounded by an absorbent element containing the product (hydror6actif) By adjusting the atmosphere, packaging for long-term storage of goods, especially foods, can be achieved. do.

Currently known techniques for regulating the atmosphere confined inside packaging be equipped with an absorbent bed to separate exudate or condensate water from packaged goods. Alternatively, an active agent such as a desiccant or bacteriostatic agent consisting of a solid powder in a bag may be used. used.

The two methods mentioned above involve mixing or impregnating an absorbent with the active substance, as the case may be. Or absorb by coating.

They are used together by placing the active substance on a synthetic support.

In fact, in order to preserve an item, food or otherwise, in its packaging, The first condition is to separate the accumulated liquid. The easiest solution is A perforated double bed is provided as described in National Patent No. 1.131.848. Is Rukoto. Other trays have sheets of absorbent paper. U.S. Patent No. 4.2 No. 75.811 provides for the separation of food to be preserved from moist absorbent materials. Absorbent materials covered with perforated impermeable sheets are described. Tokukai Showa 6 No. 1-58658 or U.S. Pat. No. 4,615,923, absorbent The bottom portion contains a hydrogelling material capable of holding an aqueous liquid. Remove liquid from items In order to obtain a better separation, in some cases French patent no. It has been proposed to provide a perforated internal double bottom as described in .

Various reactants are used to control the atmosphere, depending on the desired effect. 0 For example, packaging is used to dehydrate air, i.e. water vapor in the form of liquid water. Have a bag of silica gel or calcium chloride to trap. often packaged It is advantageous to absorb the oxygen contained therein. British Patent No. 496,935 is also mixed with other substances such as citric acid to inhibit the action of microorganisms. describes unmixed oxidizing metal products or ferrous sulfate.

European Patent No. 206.343 proposes a mixture of iron powder and electrolyte in the form of paper. provide Other patents cover products capable of absorbing oxygen obtained from the decarboxylation of metal carbonates. range, e.g. sulfites (see U.S. Pat. No. 2,825,651), bisulfites (see U.S. Pat. No. 3.169.068) or metal oxides (see U.S. Pat. No. 3.3). 61,531) or alternatively ascorbic acid or its salts (French patent 2.394,988).

The absorbents mentioned are fibers, clay, bentonite, kaolin, activated alumina and activated carbon. JP-A-55-29975 discloses oxygen absorbers and carbon dioxide. Impregnated materials coated with gas generants are described.

As in JP-A-61-145270, the powder is placed in a bag, It is advantageous to generate oxygen by the action of water. European Patent No. 128. No. 795 only includes substances capable of releasing gas under the action of an aqueous liquid in the absorption means. It also contains ingredients in food that can be prevented from deteriorating by the action of aerosols. The containing tray bottom is indicated. The above absorbent material may be a sheet or dipstick. It is.

To prevent the active agent from being deliquesced by the liquid, the absorbent can be prepared as a powder or granule. The presence of an absorbent in the form of a bag is also necessary. Because the desiccant can be reused, In U.S. Pat. No. 4,615,823, a deliquescent salt is placed in a bag by means of fibers. JP-A-56-143263 and JP-A-56-143263 and In JP-A No. 61-103523, a salt-containing liquid is placed in a bag made of a gelling agent. It is stated that it should be retained.

The activator can be a cellulose base as described in British Patent No. 863.095. It can be a bactericide sealed in a ponge.

Among the means for regulating the atmosphere inside the package, the present invention provides which becomes active under the action of a fluid released or produced by condensation of water vapor The target is

The invention solves the problem of prolonging the action of these means as much as possible. suggest something. An analysis of the prior art shows that this problem has not been addressed yet. It has been found.

In fact, when powders or granules are enclosed within a bag, they pass through the walls of the bag. Reacts immediately with liquids.

Therefore, the production of gas or active elements is no longer possible.

For example, if liquid is released gradually over the entire shelf life of the food, these of the elements by providing an excess amount compared to the amount of liquid to be recovered. It can be extended. however.

These products are relatively expensive, so this solution is not economically attractive. It's not something you can do.

Furthermore, inside the bag the powder tends to clump under the influence of humidity. thus powder The powder loses its accessibility to the liquid and the powder becomes useless.

Finally, manufacturing and filling bags is an expensive operation. This kind of support is For example, it is not economically profitable to apply it to food packaging trays. And only a small part of its value is realized by this support.

When considering coating techniques on supports, this means that The problem faced is that the amount of reactant that can be deposited is extremely limited. no longer generated In addition, the effects of certain water reactants (hydr ror6actif) can be applied without being changed by impregnation or coating. It is known that it cannot be done.

According to the present invention, these drawbacks can be overcome, especially as it is placed inside packaging for food products. , contains at least one water-reactive agent, reacts on contact with this agent, and has a small amount of capable of absorbing liquids, exudates or condensates which release at least one active ingredient. In the absorbent structure, this structure is hydrodynamic (a6rauHque). essentially fibrous mixtures formed from hydrophilic and hydrophobic materials by and in which the water-reactive agent is distributed. To provide the above-mentioned absorbent structure, characterized in that it consists of one cushion. Then it will be vindicated.

Structures as mentioned above exist in the form of knee powders or granules, which have the following advantages: The fact that the agent is distributed inside the fibrous cushion means that it will not aggregate into lumps. avoid all dangers. The article thus does not lose its effectiveness, offers the possibility of incorporating relatively large amounts of powders or granules - hydrophilic and hydrophobic The rate of wetting of the structure can be adjusted by appropriately selecting the amount of material in the can be used to adjust the duration of the reaction.

When preserving food, the critical period of preservation @ (1) LC) is clearly and reliably It can be extended to accommodate. Because it was trapped inside the packaging. This is because it can ensure a long-lasting effect on the atmosphere.

- the cushion is hydrodynamically formed, i.e. the fiber material mixing of the powder is possible as it is conveyed through the powder and then deposited on the substrate. and thus its cost is very low. Furthermore, to form a powder base, Very inexpensive materials can be selected for this purpose.

A hydrodynamic method can avoid the use of water during production or if necessary In order to strengthen the cushion, for example, the possible deterioration of water-reactive agents by water can be illustrated. It means to avoid it even if it's only partially.

This structure according to the invention preferably prevents liquid seepage into the cushion on each side. Use gauze or other transparent or impermeable filters as needed to adjust the transparency. It is covered with a layer of foam.

According to one of the preferred embodiments of the invention, the absorbent composite is in fibrous or powdered form. It can be reinforced according to known techniques using hot melt bonding agents. Similarly, spraying It is also possible to use water-based latex applied to the surface by oxidation or in the form of a foam powder. can. If the composite is strengthened in this way, one side can be covered with gauze or The need to cover with a film is avoided.

According to another advantageous embodiment of the invention, a cushion containing water-reactive substances is provided. The cushion may, for example, be made of bonded fibers having a wettability different from that of the first cushion. and increase the retardation effect and the distribution of liquid in the direction of another cushion. A buffer between the liquid source and the reactant-containing structure to control the fabric and action. It may be combined with at least one second absorbent cushion forming the element.

The absorbent cushion containing the water-reactive agent comprises at least one hydrophilic substance and A substance that is clearly less hydrophilic, i.e. hydrophobic, compared to this first substance Consisting of Furthermore, at least one of these components must be fibrous. No.

You can choose from the following mixtures: Otori Suitate Onitate Eishui Tachisodate ・Cellulose fibers, treated or untreated synthetic fibers ・Cellulose fiber latex-type binder ・Cellulose fiber hot-melt powder bond agent/hydrophilic powder/synthetic fiber ・Processed synthetic fibers Synthetic fibers - Treated synthetic fibers, latex-like and/or binders - Treated synthetic fibers, hydrophobic cellulose fibers, hydrophilic fibers, less hydrophilic Powdered cellulose fibers are compatible with the type of treatment that determines the amount of hydrophobic resin remaining. natural fibers, such as cotton or wood, made hydrophilic or hydrophobic, so as to Alternatively, recycled fibers of rayon, viscose fibers, and others are included.

The term "treated synthetic fibers" refers to materials whose surfaces increase their wettability by water. Includes synthetic fibers (PP, PE, PET, etc.) that have been significantly modified to What to do.

It is understood that (for example, Pulpec by HERCULES) PH woven fiber sold under the trade name PULPEX.

The term "hydrophobic fiber" refers to fibers of nature such as glass or metaphosphate fibers. refers to fibers that are hydrophobic in nature.

Hydrophilic powders can be mineral or organic.

Mineral powders include clay, vermiculite, glass, and others. organic Powders can be made from natural sources (guar, alginate, cellulose or modified starch). (deepening, thickening or hydrogelling products, etc.) or synthetic (polyester, etc.) (tyrene oxide, polyvinyl alcohol, polycarboxylate, etc.) , these powders are like fibers that are more or less hydrophilic because they They can be gradually wetted (hydrophobic) and/or to retain water. (hydrophilic) capable of gelling water (hydrogelable powder); Here, by introducing hydrophobic substances classified as ``low hydrophilic'' This property has the effect of slowing down the diffusion of water in pine tress.

Finally, the hydrophilic component of the mixture is one of the hydrophilic components listed above or For example, hydrophilic powders, which may be mixtures of two or more of them; In particular, hydrogelling powders can be converted into cellulose fibers.

The proportion of hydrophilic and hydrophobic substances is determined according to the intended use, i.e. present in the packaging. should be selected to obtain a wettability of the product that is compatible with the nature and quantity of the liquid. Ru. In most cases, the article is not made hydrophobic at all, i.e. does not absorb liquid. The lowest wettability will be expected.

Therefore, the amount of hydrophobic material, not counting water-reactive agents, can be between It can vary between 50% by weight.

It is important to define the term hydrophilic or hydrophobic to designate an article. Ru.

The hydrophilicity of an article depends on its surface energy. liquid liquid flat surface The smaller the difference between the surface energy of the solid and the surface of the solid, the more it will wet. For example, water with a surface energy of 72+oJ/m" has a Reester (43mJ/m”) or cellulose (36s+J/m”) or polyester Wet the lippropylene (29 mJ/+s”) well. Do not wet Teflon or PTFE with energy (1hJ/mz) .

PP, PE or even PTFE are known to be hydrophobic, so , the first surface is considered to be hydrophilic. Because their surface energy This is because ghee is clearly lower than that of water.

Additionally, RP's silicone binder RHODOR5IL 6356 ( 25+J/m”) is a phenolic bond with a surface energy of 42 mJ/a”. Mixture or epoxy adhesive EPIKOTE 82B (44,5m J/-2) is more hydrophobic.

Fortunately, the surfaces of the fibers are flat and their roughness prevents liquid from reaching this surface. change the contact angle of

To characterize the wettability of a fiber, its contact angle with water is measured, e.g. The angle of the fibers in contact with the liquid and the withdrawal when the fibers are pulled out of the liquid. "Colloids and surfaces J" (COLLOIDS) by measuring the angle AND 5URFACES”), Volume 6 (1983), pp. 49-61 It can be measured according to the method by B. Miller (B.?IILLER). preferable. For round fibers, Miller obtained the following values: Angle (°) Contact angle Pull-out angle Teflon 118 92 Polypropylene 100 78 Polystyrene (PS) 95 71 ps-polyacrylonitrile 8351 nylon 6 69 25 This method therefore allows evaluation of the degree of wetting. The above angle is less than 90° If it is large, no wetting of the fiber by water occurs, it is completely hydrophobic 0 In contrast, bleached kraft cellulose fibers have extremely low contact angles and pull-out angles. From the above, it is clear that it is completely hydrophilic. Products designated as hydrophilic and hydrophobic (in the invention) have significant contact angles with water. This means that the products are separated by a certain distance. known as hydrophilic For a fiber to be called hydrophilic, it must have an extremely low Knowing that we will have a contact angle and a withdrawal angle, the difference in angle is Must be greater than 20゛.

Contact angle measurements are crucial when evaluating the hydrophobicity or hydrophilicity of materials, especially fibers. That's true. This is because hydrophobic products can be surface treated to make them hydrophilic. This is because it is, and vice versa.

A water-reactive agent or water-reactive substance contained within an absorbent complex, as a logical consequence , sensitive to water, liquids or vapors.

This reactivity in the physico-chemical sense is e.g. hydration, its dissolution or decomposition.

For example, water can decompose hydrogenated compounds, and hydrogen in the presence of a catalyst combines with oxygen to produce oxygen-free chambers (U.S. Pat. No. 3,419,40 0), the water-reactive compound can be a soluble capsule with the active agent.

The water-reactive material may be one or more products, pure or as a mixture, is at least partially soluble, capable of combining with water, or reacting with or producing consists of inorganic or organic products that can be These include, for example, inorganic salts (N aC1, CaC1g), organic salts (gluconate and others), bases (Ca(OH)z .

NaOH, etc.) or acids (citric acid, ascorbic acid), soluble substances (1 , oxide (Cab, Mn0), peroxide (percarbonate 2NazCO3,3HiO z), hydride, encapsulated or unencapsulated metal <ha+ Fe that etc.), carboxymethylcellulose, and others.

When the water-reactive material consists of two or more components, each component is a separate component. Layered cushions where the fibers are distributed among cushions or separate layers of cushions can be formed.

Water-reactive materials are already “stabilized”, i.e. more or less exposed to water in the atmosphere. It can also be treated reactively, which also secondarily adjusts the reactivity of the material with water. This results in a delay in the timing.

Water-reactive materials can be powders, granules, flakes, laminates, vermicelli or fibers. As an example, the characteristics of the three products according to the present invention can be compared to the two according to the prior art. A comparison with that of a seed product has been described in three tests.

The first test allows the product to be evaluated for total absorption and immediate absorption. Naturally, the reaction will be delayed. In order to increase the length, low wettability is required. However, this wettability is actually Above, it is sufficient that the liquid can be absorbed as it is released.

To perform this test, place a 6 x 10 cm sample on a horizontal surface, this surface Then, tilt this support surface to an angle of 30'. Collect any excess liquid that flows away. The total absorbed amount of the sample is calculated by subtracting be done.

Next, another sample identical to the first is placed on a plane tilted at 30°. Using Beauleft, add 50% more water than the product can absorb at saturation. Pour immediately and collect excess water. Total absorption and wetting expressed as a percentage The immediate absorption amount is calculated by subtracting the amount called the amount.

The following second test is performed to assess the overall reactivity of the product. Etching a sample of the product Place in a Luhlenmeyer flask and close it with a two-hole stopper. 1st The hole is fitted with a tube that introduces water in an amount 50% greater than the total absorption of the sample. No. A water manometer that can measure the pressure generated by gas release is connected to hole 2. Ru. Measure the maximum pressure in the water column (-C) and the total reaction time, then Measure the time it takes for the value to drop to half of its high value. In this way the duration of the reaction stipulates.

The third test aims to simulate wetting of the product placed at the bottom of the container. That is.

The container is never strictly horizontal, so the liquid usually flows out of one end of the product.

W& collection is carried out by capillary tubes according to Lucas's law, and in practice It is independent of the angle of upward inclination. Klemm's test involves hanging from a balance. time by measuring the wetted height and amount of water absorbed for the sample. It makes it possible to trace the rise of the liquid expressed as a function of the time.

At the end of the experiment, total absorption was achieved by dipping the sample and then draining vertically. measure quantity.

In this way, the total absorption can be expressed as a percentage by soaking and draining at any time. be able to.

3 parts of a mixture of equimolar amounts of percarbonate and organic diacid and a supplement such as sodium chloride. A powdered water-reactive mixture is prepared from 1 part of the neutral salt used as excipient. use The percarbonate thus obtained is stabilized. In aqueous media, it is affected by the above acids. This releases oxygen (13%) and carbon dioxide gas.

It consists of a plastic grid lined with two sheets of cellulose cotton. 6X is a non-woven product sold under the product name SERICEL. Make a bag with 10cm+.

For the first test, put 0.72g in the first bag and 2g in the second bag. In both cases the total absorption rate is 5.7g and the immediate absorption rate is 88%. It turns out that

As a second test, add 2 grams to each bag.

The pressure rose rapidly and reached a height of 33 c- of water within a 2 minute reaction time. is observed. The presence of water causes gas evolution to start immediately without any delaying effect. It can be concluded that Duration is measured to be 60 minutes.

As a comparison, 2 g of water-reactive powder hydrolyzed with 12 M water has a reaction time of 5 minutes. This causes an increase in pressure in the water column 38c-. The reaction duration of this powder alone is approximately The duration is 35 minutes. In this example, along with example 2, the reaction time remains unchanged, and the reaction duration, if the powder is obtained by absorbent materials according to the prior art. This shows that it is less than twice that of the previous year.

■" Bonded by spraying of latex with a weight per unit area of 60g/■2 In addition, a layer of cellulose fiber (this product is made by Kaiserberg (Soci6t6KA) sold under the trade name HOMECEL by ) and 60g/s! Layer the sheets of the above Sericel having a unit weight of Into the bag made by combining the same amount of water solution as in Example 1 Introducing the reactive mixture.

A weight of 3.5 g containing 2 g of a water-reactive mixture having a structure according to the teachings of the prior art. A 6 x 10 cm bag with a volume of 9.7g absorption and 88% wetness (wetness is 95% without powder).

The above bag wets rapidly, favorably affecting the hydrolysis of the reactants, and the purpose Contrary to. In fact, according to the second test, the reaction to the maximum pressure of the water column 28c+++ It can be seen that the response time is shorter (3 minutes).

The reaction duration of 45 minutes is likewise shorter than in Example 1.

A third test showed that this bag was less wettable than the previous one and that water-reactive mixtures The effect of the substance is less, the total absorption is here when using 2.5g sample. It is 7.58. The absorption rates are as follows: 65% after 1 minute, 84% after 10 minutes 84% after 1 hour.

The absorption rate of this product after 1 hour is 75% greater than the volume.

■" In accordance with the present invention, absorbent composites containing the same water-reactive substances are formed. Besides that For this purpose, cellulose fiber paste (Rayflo c.Products commercially available under the trade name J)) and polyethylene synthetic pastes (fiber commercially available under the trade name S-P by Mitsui) is crushed at a ratio of 95150. do. The mixture described in Example 1 was added to the air stream containing these fibers. Add 120% water-reactive powder.

Absorb this combination onto 18g/+m” tissue paper and calendar it. Then, the hydrophobic polymer was bonded by heat bonding in an open air at a temperature of 30 to 150'C. The polyethylene 0 heat-adhesive fiber is fused. Polyethylene on one side of this combination The film is laminated to the other side with a nonwoven fabric using a hot melt adhesive.

For laminating nonwoven fabrics, tissue paper is bonded with two-component fibers of polypropylene and polyethylene. Danacron (Danacron) manufactured by JACOB IOLM This can be avoided by replacing the absorbent cushion with The bonding of the non-woven fabric to the non-woven polyethylene material and that of the absorbent cushion are This is made possible by making people wear clothes. Properties of nonwoven fabrics and finishing of the fibers that make up them The control of the processing, heating and finishing steps determines the wettability of the finished finished product.

The composition of the 530g/m" product is as follows: Neat tissue paper 18g/m m” -Cellulose fiber 200g/m” -Synthetic fiber Log/m” - Water-reactive powder 250g/m" (47%) - Adhesive 6g/m" -Polyethylene film 28g/*" -Non-woven fabric 18g/m" A 6 x 10 cm sample weighing 3.2 g will absorb 16.5 g and its moisture The moisture content is 82%. The rate of immediate absorption of large amounts of liquid may be somewhat delayed and This enables strong capillary absorption.

The reaction time of the product according to the invention is considerably extended at the same maximum pressure of 30 cm of water column. (330 minutes).

The reaction for 3.85 g of this sample containing 1.85 g of water-reactive substance was then The response duration is 485 minutes.

The amount of absorption due to capillary action was measured by immersion absorption of 12.6 g.

Regarding the yield (3.3 g of product), the This indicates that there is some moisture.

The absorption rate according to this third test is as follows: 51% after 21 minutes 10 minutes later 64% 60 minutes later 64% The absorption rate after 1 hour is clearly less than 75% of the capacity.

■" Proceed as in Example 3, but to further adjust the reactivity of the product, the fiber mixture The polyethylene fibers in the product are introduced as 15% instead of 5%.

The composition of the 400g/m” product is as follows: Neat tissue paper 18g/ m” -Cellulose fiber 160g/m” -Synthetic fiber 24g/el+” - Water-reactive powder 144g/w" (36%) - Adhesive 6g/+s" -Polyethylene film 28g/■2-Nonwoven fabric 18g10" Absorption of a sample weighing 2.2 g at 6 x 1°C containing 0.8 g of water-reactive mixture is 10.6 g and its wettability does not exceed 6%.

A sample of 7 x 12c+++ weighing 3.8 g containing 1.4 g of water-reactive mixture is: 6 According to the present invention which generates gas reaching a maximum pressure of 36 cm+ of water column in 150 minutes The desired effect was clearly achieved. In other words, gas generated over a period of time This means that it is gradually released. For a reaction time of 150 minutes, the reaction The duration is 300 minutes. These numbers are clearly based on prior art products. much higher than the numbers obtained using .

The amount absorbed by immersion for a 2.7 g sample is 8.1 g.

The absorbance due to capillarity is as follows: 1 minute later 40% 10 minutes later 57% 60 minutes later 57% The absorbency after 1 hour does not exceed 75% of the capacity, which contains only 5% hydrophobic fibers. It is inferior to that of products without it.

■" Perform the same operations as in Example 4, but in this case cover one side of the product. The above-mentioned Homecel dry-type non-woven fabric with a unit weight of 60 g/m'' I changed it to a law paper. It is an absorbent non-woven fabric whose wettability is similar to that of SWP polyethylene. larger than that of the lower layer with fibers.

This example illustrates other techniques for adding one or more operations to a multilayer composite. The step consists in placing the fibers or powder locally, e.g. in a cobblestone manner, within the fiber mass. do.

The activator is released by the reaction of two products A and B, at least One is also water-reactive, and these products A and B increase the retardation effect. The different layers or zones of the composite are carefully placed (in order).

The absorption capacity of a 6X10c garden sample weighing 2.4 g containing 1 g of water-reactive mixture is: 13.7 g and the wettability of the homeocel surface is 80%. This side is It is very hydrophilic compared to most hydrophobic surfaces containing water-reactive substances.

A 7 x 12 cm sample containing water-reactive material 1.38 The duration of the zero reaction that allows the maximum pressure of 10 cm of water to be reached within a reaction time of 1 minute is: It lasts 300 minutes. Pressure remains stable between 8 and 9 csa of water .

This complex, in which water is divided into a reactant-free zone and a reactive zone, Limiting gas release and achieving long reaction duration.

The third test showed that this composite had the highest wettability and a total absorption of 11 ．． 8g (2.8g sample).

The absorbance is as follows2 1 minute later 54% 10 minutes later 63% After 60 minutes 66.5% The absorbency after 1 hour does not exceed 75% of the capacity.

These examples demonstrate the advantages of products according to the invention compared to known products. ing. In fact, the hydrolysis time of water-reactive substances must be carefully selected and 2 compared to the claimed effect by using a highly combined absorbent material. This is because the effect is more than doubled.

This effect can be achieved using Mitsui's SWP or Hercules' Thermoplastics such as PLILPEX manufactured by IERcULEs Obtained by using 5 to 15% fiber.

These are also manufactured by JACOB Holm (JACOB ll0LI11). Polyethylene or DANAKLON ES commercial product under the trade name DANAKLON. From two-component products by product name or MELTY manufactured by Unitika , as well as spun or cut fibers, crimped or uncrimped fibers. It is also possible to melt these fibers to bond them into a fibrous cushion. It is for use. Hot-melt powders, such as low-melting powders manufactured by Eastman The use of polyester makes it possible to obtain a more flexible product.

Hydrophilic substances are fibers or natural or recycled foams, fibers or foams. or absorbent nonwoven products based on hydrophilic treated synthetic materials.

Similar partially treated materials have the desired properties of combining hydrophilic and hydrophobic properties. can be shown.

1" According to Implementation B, the dry method, that is, the hydrodynamic method, is used to fabricate fibers in the first stage. form a layer of fibers.

Next, place the powder on the surface and infiltrate it into the layer by blowing air. by suction through the thickness of the layer, or by combining these two means. This is done by combining.

This layer containing all or part of the powder may also be formed by hydrodynamic methods. contain no hydro-reactive powders or contain other parts of water-reactive powders. may be covered with another layer.

Thus, a material containing 20% polyethylene fibers and having the same composition as Example 1 A 300 g/an'' layer of cellulose fibers mixed with water-reactive powder was obtained. Ru.

This layer is thermally bonded by passing it through an oven, the rate of dissolution of the water reactant is , is checked by measuring after pouring 120 cc of water over the sample.

Thus, the water reactant alone produces a gas pressure of 16 cm of water within a 2 minute reaction time. In contrast to reaching equilibrium by releasing and react. The pressure of the gas released when equilibrium is reached is, for a reaction time of 12 minutes, The water column is 15 cm.

■Yu S-P synthetic fibers in proportions of 0%, 5% and 15% and powder by dry method. Three layers of cellulose fibers containing powdered bar carbonate are formed.

These formed layers are passed through an oven at 150°C for 6 seconds.

In order to evaluate the dissolution rate of this peroxide salt, the dissolution time was determined by a fourth test. , i.e., a sample immersed in distilled water is mixed with a solution of salts dissolved in the water by stirring. Measure the time it takes for equilibrium to be reached. The peroxide dissolution time is and the presence of hydrophobic fibers in PI3 and the hydration time of bar carbonate as above. increases by

:Item :　PO:　P5　:PI3　:P　:Cellulose:Cellulose:Se Lulose:: 0.5g: 100.5g s +5% SWP: +15% swp:=Parker:Parker:+0.5g:0.5g::Bone G: Bonato: Bar carb: Bar carb: Weight (a/m”) ：Ha■”： : At initial pH: 5.2 : 5.2 : 5.2 : 5.2 : : At pH equilibrium: 11.0:1. o: 11.0? 11.0:: Dissolution time: :pH-10.4: 14:50 50:80=■" Mixture similar to Example 7 but containing powdered citric acid instead of bar carbonate use.

In a similar manner, the dissolution rate of the acidic water reactant was determined according to the method of the fourth test, v: F4 is first immersed in distilled water whose pl+ has been adjusted to 8 using sodium hydroxide. measure by

:　Item　:　CO:　C5:　C15:　C: Cellulose: Cellulose: Cell Loin:: 0.5g: +0.5g: +5%SWP: +15%S WP:: Citric acid: Citric acid: +0.5g: 0.5g:: Citric acid : citric acid : : Per unit : : : 265 : 280 : 310 Weight (g/■t) :　shiL11　: ・ : pH initial: 8.2: 8.2: 8.2: 8.2: At pH equilibrium: 2.6: 2.6: 2.6: 2.6: if1M time; : pH-3,2 = 10: 23: 28: Taro 00 International Survey Report international search report FR8800472

Claims (11)

[Claims] 1. at least one water-reactive agent for placement within the packaging of an article, particularly a food product; containing an agent which, on contact with the agent, reacts and releases at least one active element. an absorbent adapted to absorb at least a portion of a liquid, exudate or condensate In the hydrophilic structure, the structure is composed essentially of fibers of hydrophilic and hydrophobic substances. consisting of at least one cushion formed by a hydrodynamic method with a quality mixture; The above-mentioned absorbent structure is characterized in that: 2. The hydrophilic substance is a woven fiber that may optionally be mixed with a hydrophilic powder. An absorbent structure according to claim 1, characterized in that: 3. The woven fibers are wood woven fibers, cotton woven fibers, or cellulose-based fibers such as viscose. Absorbent structure according to claim 2, characterized in that: 4. The hydrophobic substance is composed of hydrophobic fibers, binders, or powders. An absorbent structure according to any one of the preceding claims, characterized in that: 5. The cushion comprises, in addition to the water-reactive agent, 5 to 60% by weight of hydrophobic substances. An absorbent structure according to any one of the preceding claims, characterized in that: 6. Water-reactive agents can be powders, granules, flakes, laminates, vermicelli or woven fibers. An absorbent structure according to any one of the above claims, characterized in that: . 7. The permanent-reactive agent contained in the cushion is 0.0% of the cushion excluding the water-reactive agent. Absorbent structure according to claim 6, characterized in that it has a ratio of 1 to 20 times body. 8. The cushion is made of permeable gauze or impermeable material on at least one of its faces. Any one of the above claims characterized in that the invention is covered with a film of Absorbent structure with one. 9. The above-mentioned claim is characterized in that the cushion is stabilized by a binder. Absorbent structure according to any one of the ranges. 10. a second fabric such that the structure provides greater wettability than the first cushion; Any one of the above claims characterized in that it has a fibrous cushion. Absorbent structure. 11. an absorbent structure in which the water-reactive agent comprises at least two components; , the structure is comprised of at least two layers or two fibrous cushions; , each of which contains one of the components of a water-reactive agent. Absorbent structure according to any one of the following ranges.