JPS6328101B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a rubber-based hydrous composite.

Water-containing composites in which water is dispersed in rubber are highly flexible and highly functional, and are expected to be used as moisture control materials, cold insulation materials, fragrance materials, and base materials for pad materials. Conventionally, methods for manufacturing the same have been proposed. As a representative example, A-B-
Type A teleblock copolymer elastomer is dissolved in an excess amount of plasticizer under heating, an emulsifier and water are added to this to disperse the water, and emulsified with 15 to 95% by weight of a continuous phase consisting of the elastomer and plasticizer. water dispersed phase
A method for producing a hydrogel in which a W/O type emulsion containing 85 to 5% by weight is formed and then gelled by cooling to room temperature was disclosed in the Japanese Patent Publication No. 1973-
It is known from the specification of Publication No. 48895. The hydrous gel obtained by this method is highly flexible and is expected to be used in fields such as cold insulation materials, heat insulation materials, heat absorption materials, sound absorption materials, and fireproofing materials. Hydrogels have various disadvantages. In other words, in order to obtain a stable and uniform W/O emulsion, it is necessary to have a viscosity suitable for emulsification, which requires a large amount of plasticizer, and emulsification must be carried out at high temperatures. was extremely complicated. Furthermore, when fillers such as calcium carbonate, clay, magnesium carbonate, magnesium oxide, or calcium sulfate are used, the viscosity of the emulsion system may become even higher, and depending on the type of filler, W/
The water particles in the O-type emulsion are destroyed, making the emulsion unstable. Furthermore, the hydrogel obtained in this way also contains a large amount of plasticizer, so if it is left at 40 to 50°C for a long time, the plasticizer will bleed out and the plasticizer and water will separate. It was difficult to form a stable water-containing gel. Such uneven distribution of plasticizer and water causes rapid evaporation of water, reduces water content in the hydrogel, and ultimately makes the hydrogel hard. Such a phenomenon is also observed when solid rubbers such as natural rubber, synthetic polyisoprene rubber, styrene-butadiene copolymer rubber, or polybutadiene rubber are used.

For example, when such a hydrogel is made into a poultice by containing medicinal ingredients, water-soluble polymers (e.g., gelatin, carboxymethyl cellulose,
aqueous solutions (such as sodium polyacrylate or polyvinyl alcohol), humectants (such as glycerin, ethylene glycol or diethylene glycol),
Fillers with endothermic action (e.g. kaolin clay, bentonite, zinc white or titanium oxide)
Some disadvantages of conventional poultices, which are made by applying a mixture of medicinal ingredients and, in some cases, tackifying resins (e.g. rosin or polyterpenes) to a fabric such as lint cloth (e.g. The disadvantage is that the medicinal ingredient in the cataplasm is hydrophobic, so it does not mix well with the hydrophilic base component of the cataplasm, resulting in the medicinal ingredient in the cataplasm transferring too quickly.The other disadvantage is that the initial adhesion to the skin is poor. , furthermore, it becomes too hard at low temperatures), but the following drawbacks still remain unsolved. The disadvantage is that a large amount of plasticizer is used to disperse water, so the plasticizer in the resulting hydrogel becomes unevenly distributed due to heat.
As a result, water becomes unevenly distributed and water evaporates quickly, making the poultice hard, impairing its adhesion to the skin, reducing its pharmacological effect, and in some cases causing it to be missing from the skin. However, in environments with a lot of moisture, such as in the bathroom or when there is a lot of sweating during the height of summer, the absorption of moisture is too large, causing the poultice base material to flow. Some of these drawbacks are also observed in cold insulation materials that are required to have flexibility and performance that is largely unaffected by temperature and humidity.

On the other hand, a water-containing composite has been proposed in which a super-absorbent resin is mixed into rubber, which is then immersed in water to absorb water using the water-absorbing ability of the super-absorbent resin. However, this material has low water absorption and lacks flexibility, so it cannot be put to practical use as a poultice or cold pack, and is only used as a water-stopping material that requires a low water content.

As a result of various studies in view of these points, the present inventors have discovered a microorganism obtained by absorbing water into a crosslinked product of an alkali-neutralized copolymer of α-olefin and maleic anhydride or its derivatives. By dispersing the hydrogel in a matrix mainly composed of solid rubber and a plasticizer and curing it, a flexible and stable hydrated composite can be obtained, which can freely contain any functional additives. The present invention has been completed based on this discovery.

Such a water-containing composite of the present invention can be prepared by mixing a solid rubber and a plasticizer under heating to form a solid rubber of at least 3.
After preparing a solid rubber composition in such a proportion that the viscosity at 90°C (viscosity measured by a B-type viscometer) is 80,000 poise or less, the water content in the rubber composition is 10 to 80% of the total water content. It can be produced very easily by dispersing a microhydrogel containing 10 to 1000 times its own weight of water in a proportion such that the weight is %, and then curing it.

The water-containing complex of the present invention overcomes the drawbacks of poultices made from water-soluble polymers by containing the medicinal ingredients of the poultice, and has excellent flexibility, adhesion to the skin, and pharmacological effects. To provide a poultice that is not easily affected by temperature and humidity.

The solid rubbers used in the present invention include vulcanized solid rubbers that are crosslinked with so-called vulcanizing agents such as sulfur, peroxide compounds, or quinoid compounds, and thermoplastic solid rubbers that flow at high temperatures but do not flow near normal temperatures. means a solid rubber selected from the group consisting of: Among these, thermoplastic solid rubber, which exhibits fluidity at about 90° C. without crosslinking treatment and gels when cooled to around room temperature, is preferably used.

The vulcanized solid rubbers include natural rubber (NR), synthetic polyisoprene rubber (IR), isoprene-butadiene copolymer rubber, polybutadiene rubber (BR), and styrene-butadiene (random).
Copolymer rubber (SBR), styrene-isoprene (random) copolymer rubber (SIR), acrylonitrile-butadiene (random) copolymer rubber (NBR),
Acrylonitrile-isoprene (random) copolymer rubber (NIR), ethylene-propylene-diene-terpolymer (EPDM), butyl rubber (IIR)
etc. Among these, synthetic polyisoprene rubber (IR) and natural rubber (NR) are preferably used. These synthetic polyisoprene rubbers (IR) and natural rubbers (NR) have at least a molecular weight of
150000 or more is required. The solid rubber also includes a modified solid rubber containing a vinyl compound having a functional group such as a carboxyl group, a hydroxyl group, an amino group, or an epoxy group. When such a modified solid rubber is used, in addition to a so-called vulcanizing agent, it is also possible to create a water-containing composite with excellent morphological stability through crosslinking based on the reaction of introduced functional groups.

In addition, the thermoplastic solid rubber refers to a thermoplastic solid rubber that contains crystalline or glassy regions near room temperature and exhibits fluidity at a high temperature of about 90°C, but does not flow near room temperature. Examples include monovinyl-substituted aromatic compound-conjugated diene block copolymers, conjugated diene-conjugated diene block copolymers (however, one block is rich in vinyl bonds or trans-1,4 bonds, and the other is rich in vinyl bonds or trans-1,4 bonds). crystalline trans-1,4, including block copolymers rich in cis-1,4 bonds), ethylene-vinyl acetate copolymers, and natural products of balata and gutta-percha.
- Polyisoprene or crystalline 1,2-polybutadiene. Above all, water in the microhydrogel is difficult to evaporate, and at a temperature of about 90℃,
A thermoplastic rubber with a viscosity of 80,000 poise or less that can be stirred with a general stirrer, and monovinyl substituted for ease of handling such as the ability to form a flexible gel with no fluidity at room temperature. An aromatic compound-conjugated diene compound block copolymer is most preferably used. The preferably used monovinyl-substituted aromatic compound-conjugated diene block copolymer is represented by the following general formula.

(A-B) _o , (A-B) _o -A or B- (A-
B) _o Here, A represents a polymer block consisting of a monovinyl-substituted aromatic compound such as styrene or α-methylstyrene and having a glass transition temperature of 60°C or higher, and B consists of a conjugated diene compound such as butadiene or isoprene. , represents a polymer block having a glass transition temperature of 10° C. or lower, and n represents an integer of 1 to 20. At least A-B or B-A
Those in which three or more are arranged in a radial manner are also included in the above general formula. The composition ratio of the A block in these block copolymers is preferably in the range of 5 to 45% by weight, preferably 8 to 35% by weight. Further, it is desirable that the molecular weight is in the range of 20,000 to 400,000, preferably 50,000 to 250,000. Among these block copolymers, A-B
- Type A teleblock copolymers are preferably used.

The plasticizer used in the present invention means an oily substance that is liquid at room temperature, and examples of those preferably used include process oil, liquid paraffin,
Examples include machine oil, cylinder oil, transformer oil, and rosin oil.

The solid rubber and plasticizer are melted under heating at 80 to 170°C and used as a matrix component. Solid rubber is usually used in an amount of at least 3% by weight, preferably at least 5% by weight, based on the total amount of solid rubber and plastic. If the amount of solid rubber used is small, a stable water-containing composite cannot be obtained, and even if it is obtained, it will be extremely unstable against heat, making it impossible to obtain a practical water-containing composite. From this point of view, the amount of solid rubber used is preferably 10% by weight or more. The amount of plasticizer used may be such that the viscosity of the matrix component measured by a B-type viscometer at 90° C. is 80,000 poise or less, preferably 50,000 poise or less. If this viscosity exceeds 100,000 poise, it may become difficult to stir with a commonly used stirrer, which may pose a practical problem.

In the present invention, microhydrogel is produced by absorbing water into a crosslinked product of an alkali-neutralized copolymer of α-olefin and maleic anhydride or its derivatives (hereinafter simply referred to as "super absorbent resin"). be able to. The above-mentioned copolymer of α-olefin and maleic anhydride or a derivative thereof is an α-olefin such as ethylene, propylene, butene-1, isobutylene or diisobutylene, preferably an α-olefin having 2 to 12 carbon atoms. and maleic anhydride or its derivatives (e.g., maleic acid, maleic acid amide, maleic acid imide, etc.), and the copolymer is a copolymer of alkali metal hydroxide, alkaline earth metal hydroxides, ammonia or alkaline substances, particularly preferably alkali metal hydroxides such as sodium hydroxide or potassium hydroxide,
For example, it is reacted in the form of an aqueous solution to form an alkali neutralized product, and then converted into a crosslinked product (super absorbent resin) by reacting with a crosslinking agent such as an epoxy compound or a polyvalent amine.

Although it is not necessary to use the superabsorbent resin at maximum water absorption, it is cost-effective to reduce the amount of superabsorbent resin contained in the final water-containing composite. It is appropriate to use it in a water absorption state of ~1000 times, preferably 50 to 500 times.
It is desirable that the volume of each individual microhydrogel is 0.25 cm ³ or less, more preferably 0.1 cm ³ or less.
If the volume of the microhydrogel is too large, it will be difficult to uniformly disperse the microhydrogel into the matrix component, which is not preferable. If the strength of the microhydrogel is weak,
Even if a large volume of microhydrogel is used, there is a possibility that the microhydrogel will be broken into small pieces during stirring during dispersion into the matrix components.
This method is not preferable in principle because there are many restrictions on manufacturing conditions such as stirring conditions and the conditions are strict. In addition, when a medicinal ingredient is contained in a water-containing complex to form a poultice, it is desirable to use a microhydrogel having a volume of 0.08 cm ³ or less, more preferably 0.03 cm ³ or less. If the volume is too large, not only will it be difficult to uniformly disperse the powder into the matrix component, but the smoothness of the surface of the poultice will deteriorate, and in extreme cases, the surface of the poultice will become so uneven that it will not adhere closely to the skin. As a result, the function as a poultice often ceases to be expressed.

The superabsorbent resin is used in the form of powder or flakes, and its shape can be spherical, scale-like, rod-like, fibrous, or a mixture thereof, but microhydrogel formed by absorbing water Considering the volume, etc., it is appropriate to use powder or granules with a particle size of 1 mm or less, more preferably 0.5 mm or less, and scale-like pieces with a length of 2 mm or less, more preferably 1 mm or less. .

Microhydrogel is made by combining superabsorbent resin powder or flakes 10 to 1000 times its weight, preferably
It is preferably produced by adding 50 to 500 times the amount of water, but if the stirring operation and stirring time are not taken into account, when mixing superabsorbent resin powder or flakes into the matrix component, Alternatively, it may sometimes be possible to adopt a method of adding water immediately after that to form a microhydrogel. In addition,
Distilled water is most preferably used as water for producing microhydrogel, but tap water or well water can also be used.

The microhydrogel is preferably used in an amount such that the water content is 10 to 80% by weight relative to the water-containing composite.

In the present invention, it is preferable to use a surfactant having an HLB value of 2 to 15 in order to uniformly disperse the microhydrogel in the matrix component and obtain a stable water-containing composite. Specific examples of surfactants that can be used include polyoxyethylene oleyl ether, polyoxyethylene lauryl ether,
polyoxyethylene alkyl phenyl ether,
Examples include polyoxyethylene oleate, polyoxypropylene polyoxyethylene ether, sorbitan oleate, sorbitan stearate, sorbitan laurate, glycerin fatty acid ester, polyoxyethylene sorbitan oleate, and polyoxyethylene sorbitan laurate. Among them, polyoxyethylene nonyl phenyl ether and polyoxyethylene oleyl ether having an HLB value of 4 to 10 are preferably used. These can be used alone or in combination of two or more. The amount used is preferably 25 parts by weight or less, preferably 1 to 15 parts by weight, based on 100 parts by weight of the matrix component.

In the present invention, the matrix in which the microhydrogel is dispersed is cured by crosslinking or cooling. The former curing is applied to vulcanized solid rubber, and the latter curing is applied to thermoplastic solid rubber.

When using a vulcanized solid rubber as a matrix component, a vulcanizing agent such as sulfur, a peroxide compound, or a quinoid compound is added to the matrix together with rubber compounding chemicals such as a vulcanization accelerator and a vulcanization activator. It is added and mixed before or after. Vulcanization is carried out according to a conventional method at a temperature between room temperature and 90°C. Further, when using a solid rubber having a crosslinkable functional group, a crosslinking agent is added and crosslinked in the same manner as described above. When performing such crosslinking, for example, when the functional group is a carboxyl group, an acid anhydride group, or a derivative thereof, zinc oxide, calcium oxide, magnesium oxide, zinc hydroxide, calcium hydroxide, zinc resinate, or Metal compounds such as calcium resinate, epoxy resins, or amino compounds such as tetraethylenepentamine, polyamide resins, or polyethyleneimine are used in combination, and when the functional group is a hydroxyl group, isocyanate compounds are used in combination. When the functional group is an epoxy group, an epoxy resin or an amino compound is used in combination, and the crosslinking reaction is carried out at a temperature of room temperature to 90°C. In addition to this, crosslinking using electron beams or radiation may also be employed. In addition, when a thermoplastic solid rubber is used as a matrix component, the thermoplastic solid rubber having a crystalline region or a glassy region is heated at around room temperature to make it amorphous or rubbery, and then cooled. Let it harden. Note that even when thermoplastic rubber is used as the solid rubber, the above-mentioned vulcanizing agent or crosslinking agent can be used.

In the present invention, in addition to the microhydrogel component, various functional additives and conventional additives are added to the matrix component, depending on the use of the obtained water-containing composite. For example, when used as a poultice, its medicinal ingredients include salicylic acid, methyl salicylate, glycol salicylate, chili pepper extract, diphenhydramine,
-Menthol, camphor, thymol, mustard oil,
Funnel oil, funnel extract, benzyl nicotyl ester, capsaicin, hormones or vitamins, etc. are contained in a proportion of about 0.1 to 25% by weight based on the water-containing complex, and glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol , propylene glycol, dipropylene glycol, polypropylene glycol, or a polyhydric alcohol such as 1,3,5-pentanetriol. Furthermore, when used as a fragrance agent, various fragrances are added. As usual compounding agents, fillers such as kaolin clay, bentonite, silica, calcium carbonate, zinc white or titanium oxide, dyes, pigments, and even oxidative deterioration inhibitors may be added, and the amount thereof should be adjusted accordingly. It can be determined as appropriate depending on the purpose.

A typical method for producing the water-containing composite in the present invention is as follows. That is, first, the solid rubber and the plasticizer are heated at a temperature of 90°C or higher, and the solid rubber is heated to at least 3% by weight of the matrix component prepared using the solid rubber, and the viscosity at 90°C is 80,000 poise or less. Mix in appropriate proportions. On the other hand, adding 10 to 1000 times its weight of water to a super absorbent resin,
A microhydrogel containing 10 to 1000 times its own weight of water is prepared by dispersing it. The microhydrogel thus obtained is added to the matrix component maintained at about 55 to 95°C and mixed to disperse the microhydrogel in the matrix component. Functional compounding agents, ordinary compounding agents, fillers, colorants, flame retardants, fragrances, glass beads, glass fibers, etc.
It is added and mixed when preparing the matrix component or when adding the microhydrogel to the matrix component. After mixing, it is molded into the desired shape and then cured. When vulcanized rubber is used as the solid rubber, after molding, it is cured by crosslinking such as vulcanization in a conventional manner. When thermoplastic rubber is used as the solid rubber, it is cured by cooling the high-temperature system during mixing of the microhydrogel to room temperature and gelling it. When it hardens, it is molded by pouring it into a container of the desired shape.

The stirring device for mixing and dispersing the microhydrogel in the rubber matrix may be any commonly used stirrer, but propeller blades and turbines are preferably used. Mention may be made of agitators with blades, anchor blades and spiral blades. In some cases, a kneader type stirrer may be used. The high speed, high shear type stirrers required when making W/O emulsions are not required, and their use may be undesirable in some cases.

The water-containing composite obtained in this way can be used as a cold insulating material, a heat insulating material, a sound insulating material, a cushioning material, a fragrance preserving material, a flame retardant material,
It is preferably used as a humidity control agent or a poultice. In particular, when used as a poultice or cold pack, its properties are fully expressed, so the medicinal components of the poultice and the cold pack can be contained in the water-containing composite. For example, when used as a poultice,
The poultice can be put to practical use by applying a water-containing composite containing the medicinal ingredient to a cloth such as lint cloth and curing it.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto. In the examples, "parts" means "parts by weight" unless otherwise specified.

Example Block copolymer consisting of styrene and isoprene (polystyrene-polyisoprene-polystyrene type block copolymer; TR-1107 manufactured by Ciel Corporation)
16 parts, liquid paraffin 13 parts, process oil (Sansen 4240 manufactured by Sunoil Co., Ltd.) 15 parts, antioxidant
A matrix (pump base) component was prepared by stirring 0.2 part of kaolin clay and 12 parts of kaolin clay at 160°C. The viscosity of this matrix (puppy base) component at 90°C was 1050 poise. 4 parts of a surfactant (polyoxyethylene nonyl phenyl ether with an HLB value of 6) was added to 56.2 parts of this paste base material component, and mixed at 90°C using a propeller type stirrer to form a uniform matrix component. And so.

On the other hand, isobutylene-maleic anhydride copolymer (an alternating copolymer with an intrinsic viscosity of 1.00 in dimethylformamide solution at 30°C and a composition of isobutylene and maleic anhydride of 1:1; manufactured by Clareisoprene Chemical Co., Ltd.) 100 times the amount of water (distilled water ), the average volume is
A microhydrogel of 0.009 ^cm3 was prepared.

60.2 parts of the matrix component, 35.8 parts of the microhydrogel and medicinal ingredients of the cataplasm (2 parts of methyl salicylate, 1 part of l-menthol, camphor)
4 parts (consisting of 0.8 parts and 0.2 parts of thymol) were added and stirred and mixed at a rotation speed of 320 revolutions/minute while heating at 90°C to obtain a uniform and stable poultice base.

This plaster base material was applied to a lint cloth and then cooled to room temperature to harden the block copolymer consisting of styrene and isoprene to obtain a plaster.

This poultice had excellent adhesion to the skin, sufficient cooling sensation and medicinal efficacy, and even after 8 hours of application, it had superior flexibility and cooling sensation to commercially available poultices. Furthermore, when this poultice was left in an atmosphere at 50° C. or an atmosphere at 90% humidity for a long time, the flow of the base material was extremely small and did not cause any practical problems.

Claims (1)

[Claims] 1. A microhydrogel obtained by absorbing water into a crosslinked product of an alkali-neutralized copolymer of α-olefin and maleic anhydride or its derivatives, which contains solid rubber and a plasticizer as main components. A water-containing composite that is dispersed in a matrix and hardened. 2. The solid rubber is an A--B--A teleblock copolymer (wherein A represents a polymer block of a monovinyl-substituted aromatic compound and B represents a polymer block of a conjugated diene compound). The water-containing complex according to item 1. 3. The water-containing composite according to claim 1, wherein the solid rubber is polyisoprene rubber. 4. The water-containing complex according to claim 1, wherein the water-containing complex is a base material for a poultice containing a medicinal ingredient for a poultice in its matrix.