JPH01201364A - Moisture-detective water-absorptive composition and water-absorptive molding - Google Patents

Abstract

PURPOSE:To obtain a water-absorptive composition which can detect a moisture (content) and is excellent in water absorptivity, by using a water-absorptive resin as a base and adding a cobalt chloride to this base. CONSTITUTION:100pts.wt. water-absorptive resin such as a crosslinked acrylate polymer is impregnated with a solution of 0.2-20pts.wt. cobalt chloride in water or a solvent mixture of water with ethanol or the like in a concentration of 0.1% to a saturation point and dried. When the obtained composition as such or in the form of a molding such as a string is immersed in a liquid such as kerosene or gasoline or packed into a glass tube, and a gas is passed into it, it can remove water from the liquid or the gas and can simultaneously detect the water content of it.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a water-absorbing composition that has a water-absorbing resin as a base material and contains cobalt chloride, and has an excellent water-absorbing ability capable of detecting moisture. Further, a water-absorbing molded article which is made by mixing this composition with a thermoplastic resin or/and an elastomer and molded into a desired shape, which can detect moisture and has excellent water-absorbing ability itself, as well as these water-absorbing compositions or water-absorbing molded articles. The present invention relates to a method for detecting moisture using. The composition and molded product have the ability to absorb a large amount of water and the ability to change color in response to the amount of water absorbed and detect the slightest amount of water, so the amount of water absorbed by the water absorbent resin, Therefore, in addition to being able to immediately visually determine the amount of moisture in the environment, such as gas or liquid, these properties can be used for a wide range of applications such as industrial, household, gardening, and toys. be able to.

(Conventional technology) A desiccant that is currently commonly used in industrial and household applications.

Silica gel is known as a dehydrating agent, but it usually contains silica gel adsorbed with cobalt chloride, which shows a color reaction of blue when dry and pink when absorbed. This allows us to determine the degree of moisture absorption, which can be used as a guide for replacement or regeneration. However, the water absorption capacity of silica gel is only about 30% of its own weight, and it is effective for dehumidification.

Although it is suitable for removing small amounts of water such as drying, it is not suitable for removing relatively large amounts of water.

Also, a desiccant made by adsorbing cobalt chloride on zeolite is known, but this desiccant has a dew point of 120'C or less.
The purpose is to detect quantitative moisture.

(Japanese Unexamined Patent Publication No. 61-253463) On the other hand, various water-absorbing resins are currently manufactured and commercially available for water absorption and dehydration in various fields, and their water absorption capacity ranges from several hundred times to 10 times more.
Some cases have reached 00 times.

However, although all water-absorbing resins swell when they absorb water and eventually become gel-like, they have no ability to detect moisture, making it impossible to determine how much water they have absorbed. Therefore, it has long been desired in the industry to detect the actual amount of water absorbed.

(Problems to be Solved by the Invention) Conventionally used dehydrating and drying agents that can detect moisture, such as silica gel and zeolite, have a low water absorption capacity, and water absorbent resins that have a large water absorption capacity have a low moisture detection ability. There is no

In view of this situation, the present inventors have conducted various studies on dehydrating and desiccant agents that have a large water absorption capacity and moisture detection ability.
Considering the excellent water absorbing ability of water absorbing resin and the outstanding coloring property of cobalt chloride due to moisture, if cobalt chloride is added to the water absorbing resin, a composition with excellent water absorbing ability that can detect moisture that is not found in conventional products can be created. I learned that things can be damaged and came up with this invention. Generally speaking, moisture can be detected with the water-absorbing composition powder as it is, but it is necessary to blend it with other moldable polymers and mold it into the desired shape, or to mix cobalt chloride when blending the water-absorbing resin with these polymers. The same problem can be solved by molding it into the desired shape, and it is easier to handle and dry and dehydrate than the powder.

The present invention was completed by discovering that the present invention can be used in a wide variety of applications for the purpose of absorbing water.

(Means for Solving the Problems) As described above, the present invention aims to provide a water-absorbent composition and a water-absorbent molded article that can detect moisture. The present invention is a water-absorbent molded article that can detect moisture and is made by blending a water-absorbing composition containing Kobal 1 to 1 and a moldable polymer such as a thermoplastic resin or/and an elastomer and molding the mixture into a desired shape.

Since these compositions and molded bodies contain cobalt chloride, they exhibit a unique coloration depending on the amount of water they have absorbed, and the amount of water absorbed can be immediately detected. Moisture in gas or liquid can be detected.

Therefore, the present invention also provides a method for detecting moisture in gas or liquid using these water-absorbing compositions or water-absorbing molded articles.

All commercially available water-absorbent resins can be used as the water-absorbing resins used in the present invention, such as crosslinked acrylate polymers, crosslinked vinyl alcohol-acrylate copolymers, and hydrated starch-acrylonitrile graft copolymers. Examples include cross-linked products of decomposition products, cross-linked products of R powder-acrylate graft copolymer, cross-linked products of maleic anhydride kraft polyvinyl alcohol, cross-linked products of alkali salts of carboxymethylcellulose, etc. Depending on the purpose of use, and select.

Among these, crosslinked acrylate polymers are exclusively used because they have good water absorption properties and excellent blendability with other polymers.

In order to incorporate cobalt chloride into the water-absorbing resin, cobalt chloride may be dissolved in a solvent to a concentration of 0.1% or more to a saturated solution, impregnated into the water-absorbing resin, and heated to remove the solvent. The solvent can be used as long as it dissolves cobalt chloride, but water, ethanol, and methanol are usually used.

Single or mixed solvents such as acetone, ether, and glycerin are used. In view of the coloring state of the water-absorbing composition of the present invention, water, ethanol or methanol alone or a mixture of water and these alcohols generally gives preferable results. If the concentration of the solution is less than 0.1%, clear coloring will not be seen on the surface of the water-absorbent composition, and even when blended with a polymer and molded, the degree of coloring will differ depending on the type of polymer, so the type of solvent and select the concentration appropriately. In addition, when blend-molding with a polymer, it is not necessarily necessary to make the water-absorbing composition containing cobalt chloride.
Direct blending of fine powders of about 0 micron or less may allow uniform mixing, which is advantageous because a drying step is not necessary. However, depending on the type and particle size of the water-absorbing resin, and the type of thermoplastic resin or elastomer, it may not be uniform or may be mixed, so it cannot always be said that it can be mixed in powder form, and it is a case-by-case problem. Although it is not impossible to mix silica gel chazeolite with adsorbed cobalt chloride as a commercially available desiccant, it is not preferred because the particle size is usually quite large and it is difficult to pulverize it. Even if they can be made into fine powder and mixed uniformly, these desiccants themselves have low water absorption capacity as described above, and are not suitable for practical use because they do not balance with the water-absorbing resin and do not exhibit sufficient coloration. The amount of cobalt chloride contained in the water-absorbing resin can be discerned in the range of 0.2 to 20% by weight based on the weight of the water-absorbing resin, and preferably about 2 to 10%, a clear change can be obtained. If it is too small, it is undetectable, and if it is too large, not only will there be no color change beyond a certain level, but it will also affect the water absorption performance and is not preferable from an economic standpoint. This ratio can also be applied when cobalt chloride is directly added when blending the water-absorbent resin with other polymers as described above, but the color tone also depends on the type and particle size of the water-absorbent resin, and the type of thermoplastic resin or elastomer. As with the problem of solution concentration, it should be determined on a case-by-case basis to obtain good results.

In this way, the water-absorbing resin containing 1 to 1 cobal chloride can be used as it is for the purpose of the present invention as a water-absorbing composition that can detect moisture, and this state has the highest water-absorbing performance. It is usually in powder form and has no moldability, so for applications where it is difficult to handle it in powder form, it is blended with other moldable polymers, such as thermoplastic resins and/or elastomers, to form sheets, pellets, etc. depending on the application. particle,
string.

It can be molded into rings, dupes, rods, and other arbitrary shapes. It is also possible to further crush this pellet into a fine powder or to make other molded products. Although some of the uses are listed in Examples below, it is not possible to cover all the uses, so the material is molded into an appropriate shape depending on the purpose and use.

The thermoplastic resin to be blended with the water-absorbing resin or water-absorbing composition may be any moldable resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyethylene oxide, polyvinyl acetate, polyamide, etc. All can be used. Since the water-absorbing resin itself does not have thermoplasticity, there is no problem of compatibility with other resins as in the case of ordinary polymer blends, and in general, the finer the powder of the water-absorbing resin, the more evenly it can be blended. Therefore, the selection of the polymer should be determined depending on the physical properties suitable for the intended use, and the use of ethylene-vinyl acetate copolymer often yields preferable molded articles because of its flexibility. Moreover, when polyethylene oxide is used, since it is water-soluble, it temporarily maintains its shape and becomes a distinctive molded product that is convenient to handle.

Elastomers are divided into natural rubber and synthetic rubber, and synthetic rubbers include chloroprene rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, butyl rubber, fluorine rubber, ethylene propylene rubber, chlorosulfonated polyethylene, silicone rubber, and urethane rubber.

Many known rubbers such as polysulfide rubber and acrylic rubber can be used, and these should be selected depending on the application, but from the viewpoint of processability and economic efficiency, styrene is preferable.
Butadiene rubber is preferred.

Certain silicone rubbers are also suitable as water leakage fillers. Furthermore, a thermoplastic resin and an elastomer can be used in combination, and a molded article with high rubber elasticity can be obtained.

Needless to say, in the case of mixed molding, additives such as plasticizers, stabilizers, vulcanizing agents, etc. necessary for molding these other polymers alone may be used. The ratio of blending these polymers is 15 parts by weight of thermoplastic resin to 100 parts by weight of water absorbent resin.
~700 parts, preferably 50 to 500 parts, and the elastomer in a range of 25 to 700 parts, preferably 50 to 500 parts. If the amount is too small, the moldability will be poor, and if it is too large, the water absorption capacity will be reduced, so this should be determined depending on the purpose, but in general, it is preferable to have as little polymer as possible within the moldable range.

When blending thermoplastic resins, add the necessary additives and perform the usual mixing method using a ribbon blender, Henschel mixer, etc., and then extrusion molding to make tubes, strings, etc., or use a T-die to make sheets, etc. It can be molded into the shape of

Furthermore, the string can be cut into pellets, or the pellets can be crushed into a fine powder for use. Further, it can be molded into a desired shape by compression molding, injection molding, vacuum molding, blow molding, or the like.

In the case of an elastomer, necessary additives are added and mixed with an open roll, kneader, Panbury mixer, etc., and then formed into a vulcanized sheet using a hot press. In short, the mixed molding method is not limited to the same and may be carried out by appropriately using a method used for molding ordinary plastic rubber. The shapes of molded objects are pellets, sheets, strings, and rings.

It can be made into various shapes such as tubes, and the molding method and shape are determined depending on the purpose and suitability of the application.

As described above, the water-absorbing composition and water-absorbing molded article of the present invention have both excellent water-absorbing performance and moisture-detecting ability, so they can detect the amount of water absorbed by themselves, and can also be used to detect gas. It is possible to detect moisture in liquid. That is, by simply bringing these into contact with gas or liquid, it is possible to detect moisture in a much wider range than with conventional desiccants. The coloring caused by cobalt chloride is blue when anhydrous and red when it contains a lot of water, so the water-absorbing composition and molded article of the present invention also turn blue → blue-purple → purple → red-purple → red as the water content increases. Change. However, since the color changes slightly depending on the type of polymer to be blended or the type of gas or liquid, if a standard color sample is prepared in advance, moisture leakage can be immediately detected.

(Effects of the Invention) In this way, for example, the composition of the present invention as it is or in the form of a string (shaped) is immersed in a liquid such as a fuel such as kerosene or Ganrin or various lipophilic organic materials, or it is placed in a glass tube. It is possible to detect the moisture content at the same time as removing moisture from a liquid or gas by filling it with gas and passing gas through it.Also, for example, if it is formed into a sheet, ring, tube, pipe, etc., it can be used for underground cables, etc. Even if a part of the cable is damaged when used for submarine cables, etc., it absorbs the water that has entered and engraves it to prevent further water from entering, and the extent of the water that has entered can be detected, so it can be repaired, replaced, etc. It can be used as a judgment criterion.The present invention can be applied to the sealant to check for water leaks in the home, to know the degree of watering of plants, or to toys that make use of the engraving and discoloration. The scope is wide.The present invention will be explained in further detail below by showing production examples and examples.

(Example) Production Example 1 Polyacrylate crosslinked product [Product name: Aqua Keep 4S
(manufactured by Seitetsu Kagaku Kogyo Co., Ltd.) 100g with 10% cobalt chloride
It was impregnated with 50 g of an aqueous solution and dried in a hot air circulating oven adjusted to 105° C. for 16 hours to obtain a water-absorbent composition capable of detecting moisture.

Production example 2 Polyacrylate crosslinked product [Product name: Aqua Keep 10S
A water-absorbing composition capable of detecting moisture was obtained in the same manner as in Production Example 1 by impregnating H-P (manufactured by Seitetsu Kagaku Kogyo Co., Ltd.) 1009 in a 5% cobalt chloride aqueous solution 509.

Production Example 3 Starch-acrylic acid graft copolymer (trade name: Sunwet IM-1000 manufactured by Sanyo Chemical Industries, Ltd.) 1009 was impregnated with a 10% cobalt chloride aqueous methanol solution (two bottles of methanol = 70/30 weight ratio > 503). let wind dry erosion 105
It was dried in a hot air circulation oven controlled at ℃ for 16 hours to obtain 1 q of water-absorbent composition that can detect moisture.

Production Example 4 100 polymerized parts of the water-absorbing composition obtained in Production Example 1 and ethylene-
Vinyl acetate copolymer [Product name: Flowback 2010
VA=25%, MI=3'! J Tetsu Kagaku Kogyo Co., Ltd. 1
1) 100 parts, polyethylene oxide [product name: PE0
-8 manufactured by Seitetsu Kagaku Kogyo Co., Ltd.], 10 parts of polyethylene glycol #400, and 2 parts of stearic acid were mixed in a Henschel mixer and then mixed in a commercially available 30 m extruder (L/D = 2
4> pellet (4#l1llφX5), and T
A sheet with a thickness of 0.5 m was produced using a die.

Production Example 5 100 parts by weight of the water-absorbing composition obtained in Production Example 1, styrene-
137.5 parts of butadiene rubber (trade name: 22 Ball 1778J, manufactured by Nippon Pion Co., Ltd.), 50 parts of water, 10 parts of polyvinylpyrrolidone (trade name: Nylbiscol Ni-30, manufactured by BASF), atactic polypropylene [trade name: Yucatac Ni-14] (manufactured by Mitsubishi Yuka Co., Ltd.) 50 parts, bentonite 15 parts.

3 parts zinc oxide, 2 parts stearin M, 4 parts sulfur.

1.75 parts of vulcanization accelerator TT (trade name: Nick Cellar TT, manufactured by Iruuchi Shinko Co., Ltd.) and 0.7 parts of vulcanization accelerator DM (trade name: Nick Cellar DM, manufactured by Iruuchi Shinko Co., Ltd.) were kneaded in an open roll. It was then vulcanized using a hot press (15° C. for 30 minutes) to produce a 1 m thick vulcanized sheet.

Production Example 6 100 parts by weight of the water-absorbing composition obtained in Production Example 1 and styrene
Ethylene-butylene-styrene elastomer (S-EB
-3) (Product name: Elastomer AR800 Aron Kasei (
Co., Ltd.) and 50 parts of water were kneaded in a heated kneader and then hot pressed (170° C. for XIO minutes) to produce a sheet with a thickness of 1 m.

Production Example 7 100 parts by weight of the water-absorbing composition obtained in Production Example 1 and 200 parts of a moisture-curable liquid silicone sealant (trade name: KE-45, manufactured by Shin-Etsu Chemical Co., Ltd.).

10 parts of silicone oil (trade name: WM-1009 manufactured by Tsuka) were kneaded using a 59 planetary mixer and filled into a tube.

'#A Preparation Example 8 The pellets obtained in Preparation Example 4 were mechanically pulverized into powder with a particle size of 20-60 mesh. Using this, a sintered sheet with a thickness of 2M was produced by heat sintering.

Production Example 9 Ethylene-
Vinyl acetate copolymer (product name: Evatate H1010V
A=15%, MI=0.6% KoO manufactured by Sumitomo Chemical Co., Ltd.
Part O, 3 parts zinc stearate.

5 parts of foaming agent (product name: Cellmic C manufactured by Sankyo Kasei Co., Ltd.), 1 part of crosslinking agent [product name: Parryoku Dox manufactured by Noury]
．． Fill the kneading mold with one roll of the manufacturing section and heat 7L/s (13
0'CX5 minutes) A foam sheet with a thickness of 5711111 (7) was produced.

Production Example 10 To 100 parts by weight of the water-absorbing composition obtained in Production Example 1, 40 parts of polyethylene oxide [trade name: PE0-3 manufactured by Seitetsu Kagaku Kogyo Co., Ltd.] and 15 parts of polyethylene glycol #400 were added.
1 part and 2 parts of stearic acid were mixed and extruded using a Henschel mixer, and a sheet with a thickness of 1 m was produced by hot pressing (140° C. for 7 minutes).

Production Example 11 Polyacrylate crosslinked product (product name: Aqua Keep 4S
Made by Seitetsu Kagaku Kogyo Co., Ltd.) 100 heavy hanging parts and cobalt chloride powder (average particle size 50 microns > 10 parts, ethylene-vinyl acetate copolymer (trade name: Flow Pack 2010VA=
25%, MI=3 (manufactured by Seitetsu Kagaku Kogyo Co., Ltd.) 10 parts, polyethylene glycol #400 10 parts, stearic acid 2
After kneading the mixture with an open roll, a sheet with a thickness of 0.5 mm was prepared by hot pressing (140° C. for 7 minutes).

Production Example 12 Styrene-butadiene rubber [Product name: Nibol 1778J Nippon Zeon Co., Ltd.] was added to the pellets 2229 obtained in Production Example 4.
After mixing 50 g of the sample in an open roll, a sheet with a thickness of 1 m was prepared by hot pressing.

Example 1 After filling a polyethylene dupe with a diameter of 20all+ with the water-absorbing composition obtained in Production Example 2, both ends were tightly plugged and a hole with a diameter of 5In111 was made in the center of the tube by immersing it in seawater. The state of flooding was observed. After about 10 minutes, only the area near the infiltrated area changed color from purple-blue to pink. This indicates that the water-absorbing composition near the infiltration part absorbs water and swells to prevent infiltration into the interior.

Example 2 Approximately 5% of the water-absorbing composition obtained in Production Example 2 was mixed with 1000 g of an untreated water-absorbing resin (trade name: Aqua Keep 103H-P manufactured by Steel Chemical Industry Co., Ltd.), and the mixture was heated at 30°C. 9
The condition was observed after being left in an atmosphere of relative humidity of 0% RH. When water was absorbed and the water content reached approximately 50%, the color of the composition changed from purple-blue to reddish-purple.

Example 3 0.59% of the water-absorbing composition obtained in Production Example 2 was placed in a water-permeable and transparent bag, and 100% of toluene containing 10 m of water was added to the bag.
Immersed in III. After 5 minutes, the composition turned from purple-blue to pink and had absorbed all 10 m of water.

Example 4 15 g of the water-absorbing composition obtained in Production Example 3 was filled into a short glass tube with a diameter of 20 shoes, and air with a dew point of -20°C was poured at 3 n/mr n.
It was dehumidified by passing it through. After about 72 hours, the composition changed from purple-blue to red-purple.

Example 5 The pellets obtained in Production Example 4 (4 mm φ It can be judged at a glance, and the colors are glossy, making it a great prize winner.

Example 6 The pellets obtained in Production Example 4 (4#1lllφX5sn) were filled into a mold for molding goldfish, and compression molded at 140° C. to obtain a molded goldfish. When this molded object was placed in a goldfish bowl, it was initially small and purple-blue, but as time passed, the color changed to pink, and by the end of the day, the burrs had grown about 10 times as large, making it suitable for toys. It can be used as

Example 7 Two sheets of armor (20x40x0.5at) were prepared in Production Example 4.
When immersed in 100 d of kerosene containing 100% water, after 2 hours only water was absorbed and the color changed from purple-blue to pink.

Example 8 The vulcanized sheet prepared in Production Example 5 (20X40X1.0!n!
14t) was immersed in solutions 2009 with different mixing ratios of water and methanol, and the amount of absorption and color reaction were observed. When the moisture content was 20%, the saturated absorption rate was 15% and there was not much change in color, but when the moisture content reached 80%, the absorption rate increased to 200% and the color changed from purple-blue to pink. . As the amount of water increases, the amount of absorption also increases and the color changes from purple-blue to pink, so it is possible to roughly determine the water concentration in alcohol to a certain extent.

Example 9 The sheet obtained in Production Example 6 (20X40X1.Omt) was
When suspended in a transparent glass container whose relative humidity was adjusted to 0%, 75%, and 90% relative humidity, the color changes depending on the humidity difference, making it possible to roughly detect the humidity.

Example 10 The tubed filling prepared in Production Example 7 was used to seal a water pipe joint in a sink to repair a leak. 1
When Shun 4th inspected the seal, he found no water leaks, but the color had changed from purple-blue to pink in some areas, making it clear where the leaks were.

Example 11 The sintered sheet (porous body) obtained in Production Example 8 was
The strips were cut into 100 mm strips and immersed vertically in a mixture of 50 ml of gasoline and 50 d of water separated into two layers.

When the sheet is removed after 10 minutes, only the portion that has come into contact with water changes color from purple-blue to pink, and the amount of water can be easily calculated by measuring the height of the discolored portion. For example, it can be used to check the water content in underground tanks of gas stations, etc., and it is also possible to completely remove water by immersing a sheet corresponding to the water content.

Example 12! ! A pressed flower was prepared by sandwiching a flower between two foam sheets obtained in Example 9 and placing a weight on top of the flower. When Shun 1st removed the weight and took out the flowers, the water in the flowers was removed by two foam sheets, creating beautiful pressed flowers. It was found that after the foam sheet was used about 5 times, the color changed from purple-blue to pink and the dehydration effect decreased. When this sheet is dried at 75°C, it returns to its original purple-blue color and is fully reusable.

Example 13 In Production Example 10, the sheet No. 19 was used for the same purpose as in Examples 7 to 9, but it quickly showed coloration.

Since polyethylene oxide is water-soluble, it comes into direct contact with water, and a swelling property close to that obtained when the water-absorbing resin is used alone was obtained.

Example 14 The sheet obtained in Production Example 11 was cut into a circle of 30 mφ and artificial urine was poured into it from the inside of an adult diaper containing water-absorbing resin.
When I observed the outside condition of Shun 5 Min Shun after 00m drop, I found that the color of the circular sheet set inside the waterproof film had changed from purple-blue to pink.

Example 15 The sheet obtained in Production Example 12 has more rubber elasticity than a normal EVA sheet, and a sheet with a good surface condition can be obtained only by roll processing. This sheet produced the same effects as Examples 7-9. Furthermore, this sheet was more elastic and therefore easier to handle.

Applicant: Steel Chemical Industry Co., Ltd. Representative Masu 1) Yuji

Claims (11)

[Claims] (1) A water-absorbing composition capable of detecting moisture, comprising a water-absorbing resin containing cobalt chloride. (2) The composition according to claim (1), wherein the water-absorbing resin is a crosslinked acrylate polymer. (3) The composition according to claim (1), which is obtained by impregnating a water-absorbing resin with an aqueous cobalt chloride solution and then drying it. (4) A moisture-detectable water-absorbing molded article made by mixing a water-absorbing resin, cobalt chloride, a thermoplastic resin or/and an elastomer, and molding the mixture into a desired shape. (5) A moisture-detectable water-absorbing molded article obtained by mixing the water-absorbing composition according to claims (1) to (3) with a thermoplastic resin or/and an elastomer and molding the mixture into a desired shape. (6) The molded article according to claim (4) or (5), wherein the thermoplastic resin is an ethylene-vinyl acetate copolymer. (7) The molded article according to claim (4) or (5), wherein the thermoplastic resin is polyethylene oxide. (8) The molded article according to claim (4) or (5), wherein the elastomer is styrene-butadiene rubber. (9) The molded article according to claim (4) or (5), wherein the elastomer is silicone rubber. (10) Claims in which the blending ratio of cobalt chloride is 0.2 to 20 parts by weight per 100 parts by weight of the water absorbent resin (
The water-absorbing composition or water-absorbing molded article according to 1), (4) or (5). (11) Claims (1) to (3) or (10)
The composition described or claims (4) to (10)
A method for detecting moisture contained in the molded product by bringing it into contact with gas or liquid.