JPS6011738B2 - Hydrogel - Google Patents

Description

[Detailed description of the invention] This invention relates to a hydrogel.

Conventional hydrogel and oily gel (gel without water)
There is no material that has flexibility, cold retention, non-combustibility, and elasticity.

For example, hydrogels made of water-soluble polymer compounds such as starch, fiber gelatin, gelatin, casein, polyvinyl alcohol, polyacrylic acid, and polyethylene oxide, which are known as relatively flexible gels, have cold retention, Although it has non-combustibility, it has almost no elasticity, and on the other hand, the A-B-A type vulcanized elastic block copolymer and paraffin oil or higher fatty acid proposed in Fin Publication No. 47-18409. The oil-based gel consisting of is prepared as a gel having flexibility and high elasticity, but since it does not contain water, it is combustible and has poor cold retention properties. In addition, most of the water-containing gels mentioned above are in the form of water-soluble polymer compounds that absorb water and swell.If the water content is relatively high, the strength becomes weak and lacks long-term stability, meaning that it cannot be left in the atmosphere. This has the disadvantage that water evaporates easily, and when cooled to a low temperature below 0°C, the entire body freezes and becomes extremely hard and brittle, with no flexibility at all. Regarding sex, it cannot be said that it is satisfactory.

In addition, the oil-based gel mentioned above has so-called rubber-like rebound elasticity, so that it easily deforms when external force is applied to it, but instantly recovers to its original state when the external force is removed; when the external force is removed, it gradually returns to its original state. It does not show stress dispersion characteristics that return to . In this way, conventional hydrogels and oil-based gels each have contradictory or individual defects in their properties, and these defects naturally narrow their range of use, and the current situation is that they are not used effectively for each purpose. be.

Therefore, one object of the present invention is to provide a hydrogel that has flexibility as well as the three properties of cold retention, non-combustibility, and elasticity. Another purpose of our research is to provide a hydrogel that has excellent long-term stability and flexibility at low temperatures, and has improved cold retention properties. is intended to provide. In the course of many years of research to achieve the above object, the inventor uniformly dissolved natural rubber or synthetic rubber in oil such as machine oil or a paraffin bottle, and emulsified and dispersed a specific proportion of water into the W/ When this emulsion was made into an O-type emulsion and cross-linked in the presence of a cross-linking agent, it was discovered that the resulting hydrogel had all of the properties aimed at by this invention as described above, and as a result of further research, this was finally achieved. This led to the completion of the invention.

That is, this invention is a W-O type emulsion in which 85-5% by weight of water dispersion is emulsified and dispersed in 15-95% by weight of homogeneous dispersed soot containing a high-boiling oily substance and rubbery substances such as natural rubber and synthetic rubber. This relates to a water-containing gel obtained by cross-linking and gelling in the presence of a mulching agent. The high-boiling oil substance used in this invention is a high-boiling compound that has extremely low transpiration in the temperature range during production or use of the hydrogel, and is selected from a compound capable of dissolving rubbery substances.

Compounds that are liquid at room temperature and have the above characteristics include machine oil, cylinder oil, rosin oil, naphthenic oil, paraffin oil as a liquid petroleum product, or higher fatty acids such as oleic acid, preferably one of these or Use two or more types. In addition, paraffin wax with a melting point of 12,000 or less and a melting point of 150
A compound that exhibits an oily form upon heating, such as waxy low molecular weight polyethylene having a molecular weight below qo, may be added and used. There is no need to select a special type of rubber for use in the present invention, and ordinary natural rubber or synthetic rubber such as isoprene rubber, butadiene rubber, or styrene-butadiene rubber can be effectively used.

The proportion to be used can be determined depending on the water content and flexibility of the final gel, and is usually in the range of 4 to 3 parts by weight per 10 parts by weight of the oily substance. If it is too small, it will become a chicken-tropic liquid even after crosslinking treatment, making it impossible to obtain a sufficiently stable gel. On the other hand, if it is too large, it will become extremely viscous, making processing and molding difficult. The homogeneous dispersed soot in this invention uniformly dissolves the above-mentioned rubber material in the above-mentioned oily substance, and if necessary, without losing the stability of the final gel,
Antiaging agents, antioxidants, ultraviolet absorbers, etc. to prevent gels from thermal deterioration, oxidative deterioration, photodegradation, etc., and fillers such as coloring pigments, dyes, and fragrances to give special functions to gels. In addition, reinforcing fillers such as carbon black, Aerosil, titanium white, calcium carbonate, and various clays are added.

The W/O emulsion in this invention is made by stably emulsifying and dispersing water dispersoid in such a homogeneous dispersion system.The water dispersoid used here may be pure water, tap water, It may also contain ions such as certain metal ions and halogen ions, such as natural water.
In addition, when fillers such as coloring pigments, dyes, and fragrances that are sometimes added to homogeneously dispersed soot are water-removalable, these fillers are added to the water in a proportion that does not interfere with emulsification and dispersion. It may be.

Emulsification and dispersion may be carried out using a suitable emulsifier, and particularly suitable emulsifiers include nonionic surfactants such as polyethylene glycol oleyl ether, polyethylene glycol nonylphenyl ether, polyethylene glycol decyl phenyl ether, and sorbitan lauryl ether. Examples of commercially available products include Noigen EA, Noigen ET, and Solgen manufactured by Daiichi Kogyo Seiyaku Co., Ltd. The amount used naturally depends on the type of homogeneous dispersed soot and the amount of water dispersoid used. Although it varies, usually 1 to 2 parts by weight per 100 parts by weight of water, preferably 5 to 1 parts by weight.
It may be the weight part. The proportion of the homogeneous dispersion and the aqueous dispersoid must be 15 to 95% by weight for the former and 85 to 5% by weight for the latter.

If the amount of water dispersoid exceeds 85% by weight, the stability of the final gel will deteriorate, or in extreme cases, the W/O type will undergo phase inversion, resulting in a W/O type emulsion and the desired properties of the former cannot be obtained. do not have. On the other hand, if the aqueous dispersoid is less than 5% by weight, in other words, if the homogeneously dispersed soot is more than 95% by weight, it is impossible to obtain a hydrogel with good cold retention properties. The water-containing gel that is the object of this invention is obtained by crosslinking and gelling the W0 type emulsion described above in the presence of a suitable crosslinking agent. Vulcanizing agents commonly used in commercially available polymers can be used, and accelerators and vulcanization aids may be used in conjunction with these crosslinking agents.

Specific examples of peroxides include hydrogen peroxide or methyl ethyl ketone peroxide, cyclohexanone peroxide, cumene hydro/gu oxide, dicumyl peroxide, acetyl peroxide, lauroyl peroxide, penzoyl peroxide, t-butyl peroxide,
Examples include various organic peroxides such as t-butylperoxybenzoate and peracetic acid. These peroxides can be used alone or in combination of two or more, and if necessary, they can be used in the form of a paste by dissolving or dispersing them in dioctyl phthalate, dibutyl phthalate, toluene, etc. The usage ratio can be determined as appropriate depending on the type of peroxide, and is usually 0.05 to 15 parts by weight per 100 parts by weight of the rubber material.
Part by weight: preferably 0.5 to 5 parts by weight. As peroxide crosslinking accelerators, amines such as N-N-dimethylbenzylamine, tri-2,4,6-dimethylaminomethylphenol, tetraethylenebentamine, and triethylenediamine, cobalt naphthenate, and octenoic acid are used. Examples include metal compounds such as tin. Further, as the vulcanizing agent, vulcanization accelerator, and vulcanizing aid, conventionally known ordinary ones may be selected, such as sulfur, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and tetrabutylthiuram disulfide. Methylthiuram monosulfide, dibentamethylenethiuram tetrasulfide, mercaptobenzothiazole, piverizine bentamethylene dithiocar/dimate, zinc dimethyl dithiocarbamate, zinc diethyl dithiocarbamate,
Examples include zinc di-butyl dithiocarbamate, sodium dimethyl dithiocarbamate, sodium diethyldithiocarbamate, copper dimethyl dithiocarbamate, zinc white, magnesium oxide, and stearic acid. The total amount of these vulcanizing agents may be 0.1 to 15 parts by weight, preferably 1 to 1 part by weight, based on the weight of the rubber material 10.

The crosslinking treatment is carried out by pouring the W/O emulsion containing the above-mentioned crosslinking agent into a desired mold, extruding it with an extruder, or applying it to the surface of cloth, paper, release paper, etc. using a coating device. According to this method, it is possible to directly form a gel product in the form of a sheet or film by crosslinking.The preferred method for producing the hydrogel of this invention is to uniformly dissolve the rubbery substance in an oily substance with a high boiling point. The emulsified powder and the aqueous dispersoid are sequentially added to this dispersion medium to form a W/O emulsion in which the aqueous dispersoid is stably emulsified and dispersed in the homogeneously dispersed soot, and then this emulsion is A recommended method is to add a crosslinking agent to the homogeneous dispersion medium and then perform a crosslinking process to crosslink the rubbery substance contained in the homogeneous dispersion medium to gel the entire emulsion.In this case, the homogeneous dispersion medium is prepared at room temperature or under heating. The formation of a W/O emulsion is preferably carried out at a temperature of 80 to 100 °C under atmospheric pressure, and the crosslinking treatment is carried out without pressure at room temperature or heated to 50 to 90 qC, or in an autoclave. 90-15000 under pressure of 1.5-6k9/ground
You can do this by heating it up to

It is advantageous for the production of a stable emulsion to add the emulsifier used to produce the W/O emulsion alone after preparing the homogeneously dispersed soot by the above method, and then gradually add the water dispersoid.

However, if particularly desired, other means may be adopted, for example, it may be added in a state of being dissolved or dispersed in an aqueous dispersoid, or it may be added in advance to an oily substance at the time of preparing a homogeneous dispersion medium. In addition, when preparing a homogeneous dispersion medium for crosslinking treatment, use a ball mill, colloid mill, etc. when preparing a homogeneous dispersion soot when the crosslinking agent used is hardly decomposed. It can also be suspended in an oily substance in advance, or it can be added in a suspended state in a portion of an oily substance using the same method as above, rather than being added alone after forming a W/O emulsion. You can also do it.

However, if the crosslinking agent is added alone after the W/O emulsion is produced using the above method, there is no need to worry about the crosslinking agent being dispersed during the preparation of a homogeneous dispersion medium, and there is no problem in producing a stable W/O emulsion. , the crosslinking effect is better expressed, and a hydrogel having desired properties can be obtained. The hydrogel produced in this way has a new structure in which water particles are dispersed and encapsulated in the gel structure, and has flexibility that varies depending on the amount of water content. It possesses cold retention and non-combustibility or self-extinguishing properties as a hydrogel, and also has good elasticity, which was not seen in conventional hydrogels. In addition, the above-mentioned elasticity is not rubber-like elasticity like the conventional oil-based gel, and it easily deforms when external force is applied, but during this deformation, the water contained in the gel acts to absorb or disperse stress. However, when the external force is removed, the deformation gradually recovers, and the material exhibits stress dispersion characteristics, typically returning to its original shape after about 1 to 2 minutes. Also, unlike the conventional hydrogel which is made by absorbing water and swelling with the water-soluble polymer compound mentioned above, the contained water is encapsulated in the gel structure as water particles as mentioned above, so the amount of water stored can be reduced. Regardless of the amount, the gel itself is strong and almost no water evaporates even if left in the air for a long time, and even at low temperatures of about -20 qo, the entire gel does not freeze, only the water particles within the gel structure freeze. The gel maintains its original shape and dimensions even when cooled or heated from -30°C to 95°C without losing its flexibility, and it does not freeze within the gel structure even when left in an overflow room after cooling to a low temperature. The water particles in the water are not easily affected by the external atmosphere, so they do not heat up easily.
Therefore, it has better cold retention than the conventional water gel. For the same reason that it has excellent cold retention, it also has good heat retention, and also has various properties such as heat absorption, lubricity, water resistance, and sustained release properties. In this way, the hydrous gel of this invention has both the characteristics of the conventional water-based gel and the oil-based gel, and also has excellent characteristics not found in conventional gels, and can be used in sheet, pad, mat, etc. It can be extremely effectively used in a wide range of conventional and new applications, such as cold insulation materials, heat insulation materials, extinguishing materials, heat absorption materials, lubricants, sustained release materials, anti-congestion materials, etc. in various forms.

Next, the present invention will be explained in more detail based on examples.

In addition, in the following, parts indicate parts by weight. Example 1 A Sanllo flask equipped with an efficient attenuator, reflux condenser, and nitrogen gas inlet was equipped with a viscosity of 170 centipoise (2
Add 10 parts of liquid paraffin (manufactured by Wako Pure Chemical Industries, Ltd., grade 1 reagent) and 8 parts of natural rubber (grade 1 veil crepe, masticated for 7 minutes) of liquid paraffin (as measured by a B-type rotational viscometer) in a nitrogen stream. It is heated to 80% to completely melt and form a viscous, uniformly dispersed butter.

After adding 6 parts of an emulsifier (Noigen EA-50, trade name manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to this dispersion medium and dissolving it, add 100 parts of distilled water while keeping the temperature inside the flask at 50 to 6,000. was gradually added dropwise over about 2 hours to produce a W/O emulsion in which distilled water was emulsified and dispersed in the fraction medium. After adding 0.3 parts of lauroyl peroxide treated in emulsion 10 and thoroughly dispersing it, it was poured into a mold and heated in an autoclave at 10 mm for 35 minutes under a pressure of 2 mm to crosslink it. Upon treatment, a hydrogel having a volume of 100 x 100 x 5Q mosquito flexibility was obtained.

Example 2 Liquid paraffin with a viscosity of 22 centipoise (2000)
Sumoil P-55 (manufactured by Matsumura Oil Research Institute Co., Ltd., trade name) and 10 parts of isoprene rubber were dissolved in the same machine as in Example 1 to obtain a homogeneous dispersion.

After adding 1 part of an emulsifier (Noigen EA-50, trade name manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to this dispersed soot, 30 parts of ion-exchanged water was added dropwise in the same manner as in Example 1 to ion-exchange the dispersion medium. A W/O type emulsion in which water is emulsified and dispersed is generated. This white emulsion is a paste made by dispersing penzoyl peroxide in dioctyl phthalate (trade name: Nypa-B○, manufactured by NOF Corporation,
After adding 0.25 part of benzyl peroxide content (50%) and 0.1 part of N.N-dimethylalinine and dispersing them well, the three powders were poured into a mold and heated at 8000°C to crosslink them. Upon treatment, a flexible hydrogel with a volume of 300x300x5 was obtained.

Example 3 Liquid paraffin with a viscosity of 180 centipoise (20°C)
Smol P-350 (manufactured by Matsumura Oil Research Institute, trade name) 10 parts of isoprene rubber was dissolved in the same manner as in Example 1 to obtain a homogeneous dispersion medium.

After adding 1 part of an emulsifier (Nigen EA-7, trade name manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) to the dispersed soot, 25 parts of tap water was emulsified and dispersed in the same manner as in Example 1 to form a W/O emulsion. generate. After adding 0.25 parts of cumyl hydroperoxide and 0.1 part of cobalt naphthenate to 10 parts of this white emulsion and thoroughly dispersing it, the mixture was poured into a mold and placed in a sealed container for 5 to 7 hours. When the pad was left to stand for a day and cross-linked, a flexible hydrogel pad having a volume of 100 x 200 x 1 ton was obtained.

Example 4 0.2 part of tetramethylthiuram disulfide and 1 part of zinc stearate were added to the W/O emulsion described in Example 3, and the mixture was well dispersed. 2 at 100℃ under pressure of
When cross-linked by heating for 8 minutes, the volume was 100 x 20
A hydrogel pad having a flexibility of 0xIW was obtained.

Example 5 Machine oil with a viscosity of 330 centipoise (20°C) (Daphne Mechanical Oil - Mechanic 75: trade name manufactured by Idemitsu Kosan Co., Ltd.), 8 anchor parts, 0 parts of paraffin wax with a melting point of 45°C and 12 parts of isoprene rubber were added. The soot was dissolved in the same manner as in Example 1, and 3 parts of Shirasu balloons (manufactured by Shirasu Co., Ltd.) having an average particle size of 150 microns per 10 pieces of the melt were well dispersed to obtain a homogeneously dispersed soot.

7 parts of an emulsifier (Inogen EA-83, trade name manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to this dispersion medium, and 10 parts of a 25% sodium carbonate aqueous solution was emulsified and dispersed in the same manner as in Example 1.
Make a mold emulsion. Separately, a mixture of 1 part of dibentamethylenethiuram tetrasulfide, 1 part of zinc dimethyl dithiocarbamate, 2 parts of zinc stearate, and 12 parts of liquid paraffin (as described in Example 3) was vulcanized by passing it through a colloid mill. Make a suspension of the agent. The above W/
After adding 2 parts of the above suspension to 100 parts of O-type emulsion and dispersing it, it was coated on a silicone resin-treated release paper in the form of a sheet with a thickness of 2 skins, and 5k9 in an autoclave.
When crosslinking was carried out by heating at 150° C. for 1 hour under pressure, a hydrogel sheet having the desired flexibility was obtained. Example 6 Viscosity 400 centipoise (20℃
) of liquid paraffin (Kyodo Liquid Paraffin - 35, trade name manufactured by Kyodo Sekiyu Co., Ltd.), 1 base of atactic polypropylene with an average molecular weight of about 5000 and a softening point of 105 OO, and 15 parts of butadiene rubber as in Example 1. Dissolve in the same manner to obtain a homogeneous dispersion medium.

After adding 5 parts of Sorgen-50 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier to this dispersion medium, distilled water was added for 3 dollars, and higher alcohol (Softanol, trade name manufactured by Nippon Shokubai Kagaku Co., Ltd.) was added to the solution.
．． 5 parts and Hasegawa Perfume Co., Ltd. fragrance No. A mixture consisting of 5 parts of 4744 was gradually added in the same manner as in Example 1 and emulsified and dispersed to produce a W/O emulsion. Add 0.0% tetramethylthiuram disulfide to 100 parts of the above emulsion. After adding and dispersing the powder, 0.5 part of stearic acid, 5 parts of zinc white, and 2 parts of titanium white, it was poured into a mold and heated to 120 qo under pressure in an autoclave.
When cross-linked by heating for 15 minutes, the volume was 30 x 3.
A pale yellow, flexible hydrogel with a 0×1 diameter was obtained.

Comparative Example 1 A mixture consisting of 5 parts of carboxymethyl cellulose and 95 parts of tap water was poured over the mixture to a volume of approximately 70% to obtain a gel-like melt, and this melt was poured into a mold and cooled. As a result, a comparatively flexible hydrogel pad having a volume of 100 x 200 x 1 volume was obtained.

Comparative Example 2 1. Machine oil (Daphne Mechanic Oil-Mechanic 75, manufactured by Idemitsu Kosan Co., Ltd.) in the beaker; Add 10 parts of the liquid and heat to about 130°C to dissolve.

This melt was poured into the same mold as in Example 1 and cooled to obtain a flexible oil-based gel with a volume of 100 x 100 x 5 mm. The hydrogels of the present invention according to Examples 1 to 6 described above all have cold retention and non-flammability as hydrogels, and also have elasticity not found in conventional hydrogels.

The above fact is also clear from the test results shown below as an example. Elasticity Test> The modulus of the hydrogels according to Examples 1 and 2 at 200% elongation at 20 qo was examined and showed a value of 29 to 35 m/m.

On the other hand, the conventional hydrogel (Comparative Example 1) has no elasticity at all. <
Cold retention test> The hydrous gels according to Examples 2 to 4 were placed in the freezer at -20:00.
~Misaki After being left for an hour, it was taken out into the atmosphere and the progress until the entire hydrous gel recovered to room temperature was investigated, and the results were as shown in FIG.

The results of Comparative Examples 1 and 2 are also shown for reference in the figure. However, in both cases, gels with a gel size of 100 x 200 x 1 inch are used. It can be seen from the figure that the hydrogel of the present invention is superior not only to the conventional oil-based gel (Comparative Example 2) but also to the conventional hydrogel (Comparative Example 1). <Non-flammability test> When the hydrous gel sheet according to Example 5 was brought into contact with flame,
It burns slightly while in contact, but self-extinguishes as soon as the flame is removed, and the strong adhesion of this gel sheet to glass, wood materials, and paper can be used to coat the surface of crepe paper, for example, with the gel sheet. When a lit cigarette was then placed on this laminate, the cigarette flame was extinguished by the hydrous gel sheet, and no burning of the paper pieces was observed.

On the other hand, the hydrous gel according to Comparative Example 1 did not exhibit remarkable self-extinguishing properties as in the above-described invention, and the oil-based gel according to Comparative Example 2 burned immediately when a fire was brought close to it. Next, various remarkable properties other than the above-mentioned properties possessed by the hydrogel of the present invention will be clarified from the following test results shown as an example.

Stress dispersion characteristics>'11 Test using a transmission type stress measuring device rheometer (manufactured by Fuji Rika Kogyo Co., Ltd., model RUD-J).

Regarding the water-containing gel according to Example 1, as shown in FIG. 2, a steel metal ball with a diameter of 18 legs and a weight of 34.5 mm was attached to a rheometer main body (not shown) and a moving arm A. B
was gradually submerged in the hydrous gel C above, and the relationship between the penetration distance of the metal ball and the stress applied to the rod was investigated, and it was found that the metal ball was buried in the gel when the penetration distance was 3. The repulsive stress on the rod in this condition was as low as about 330.

Moreover, when the metal sphere was removed, the hydrous gel completely recovered to its original shape after about 1.6 minutes. On the other hand, when the same test as above was carried out on the conventional oil-based gel according to Comparative Example 2, the stress applied to the rod was a very large value of about 1,800 mm, and when the metal ball was removed, it instantly recovered to its original shape. did. '2
) Test using the self-weight of a steel metal ball. When a steel metal ball with a diameter of 10 mm and a weight of 5K9 was placed on the hydrous gel according to Example 2, the metal ball was sufficiently buried in the hydrogel after 4 anchoring hours, and the metal ball was taken out. The hydrogel completely recovered to its original shape after about 2 minutes, and no deformation was observed.

From the results of 1 and 2, it can be seen that the oil-based gel of Comparative Example 2 is a highly elastic gel that does not have stress dispersion properties, whereas the hydrogel of the present invention is flexible and tough and has excellent stress dispersion properties. It is clear that this property indicates that this type of hydrogel can be effectively used to prevent congestion caused by pressure on the lumbar region of patients who have been sick for a long time.

<Long-term stability test> The hydrogels according to Examples 1 and 3 were tested at room temperature (20 x 0).
After being left for days, the gel weight reduction rate was 1.2.
% and as low as 0.9%.

On the other hand, the hydrous gel according to Comparative Example 1 had a large value of 29% and was unable to maintain its original shape and dimensions. <
Low-temperature and high-temperature stability test> When the hydrous gel according to Example 1 was left at a low temperature of -500 oo and a high temperature of 95 oo to examine its properties, it was found that even under these conditions, its original shape and dimensions remained the same. was held.

<Flexibility test under low temperature> The hydrous gels according to Examples 2 to 4 were placed in a freezing room at -2000 °C for 8
When taken out after being left to feed for ~1 hour, Example 2 had enough flexibility to deform by pressing with the fingertips even immediately after that, and Examples 3 and 4 had enough flexibility to be deformed by pressing with the fingertips. It has sufficient flexibility so that it can be wrapped into shapes.

On the other hand, the hydrous gel according to Comparative Example 1 was placed in a -1oo0 freezing room for 2 hours.
If left for 4 hours, the entire body would freeze and lose all flexibility, making it impossible to wrap it around the wrist. <Water Resistance Test> When the hydrogels according to Examples 1 and 3 were soaked in water for one hour, almost no deformation of the gels was observed.

On the other hand, in the case of the hydrogel according to Comparative Example 1, the entire gel swelled and deformation was noticeable. <Conformity Test> When the hydrogel according to Example 6 was left at room temperature (20 oo), no fragrance odor was observed even after 90 days.

This shows that the above-mentioned hydrogel has the ability to adjust the rate of fragrance release. It is clear from the above test results that the hydrous gel of this invention is far superior to conventional hydrogels and oil-based gels, and if this characteristic is utilized, it can be used as a cold storage material in addition to the above-mentioned anti-congestion material. It can be seen that it can be effectively used for applications such as wood, fireproofing material, and free-flowing material.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the protection properties of the hydrogel of the present invention and conventional hydrogels and oil-based gels, and FIG. 2 is an explanatory diagram for measuring the stress dispersion properties of the hydrogel.

Figure 1 Figure 2

Claims (1)

[Claims] 1 A homogeneous dispersion medium containing a high boiling point oily substance and a rubbery substance such as natural rubber or synthetic rubber is mixed with 15 to 95% by weight of water dispersoid.
A water-containing gel obtained by crosslinking and gelling a W/O emulsion in which 5 to 5% by weight is emulsified and dispersed in the presence of a crosslinking agent.