JP5136818B2 - Base for plaster and plaster - Google Patents

Description

The present invention uses a base for constituting a poultice and a base for a poultice formed by applying a hydrogel plaster comprising a medicinal component or moisture to a support such as a nonwoven fabric or a woven or knitted fabric. It relates to a plaster and relates to a technique for producing a poultice.

Traditionally, poultices made by mixing medicinal ingredients, moisture and other ingredients on a substrate such as a nonwoven fabric or woven or knitted fabric have been combined with polyacrylic acid or polymethacrylic acid (hereinafter referred to as acrylic and methacrylic). (Meth) acrylic polymers) or (meth) acrylic acid polymers having a carboxyl group such as poly (meth) acrylates such as sodium poly (meth) acrylate are used.
In particular, a partially neutralized polyacrylic acid, in which a part of the carboxyl group of polyacrylic acid has been neutralized with sodium hydroxide, etc. is excellent in water retention as a poultice, and adheres to the skin during use, after use It is widely used because it has many advantages in its peelability.

For example, in Japanese Patent Application Laid-Open No. 58-21612 (Patent Document 1), in order to obtain a base for a poultice having excellent adhesion to skin, peelability after use, and water retention, α, β- In polymerization or copolymerization of a saturated carboxylic acid or a salt thereof, the polyfunctional crosslinking agent is 10 ⁻⁴ to 10 ⁻² mol% based on the total amount of monomers, the reaction initiation temperature is −5 to 40 ° C., and the polymerization catalyst amount Is a polycarboxylic acid-based crosslink having a pH of 8 or less and a water-soluble portion of 10 to 70% by weight obtained by copolymerizing the polymer with ^10-5 to ^10-1 % by weight based on the total amount of monomers the copolymer as an active ingredient, which is the mounting technique Subegaki adding the 0.5 to 15 wt% in the poultice.

Japanese Patent Application Laid-Open No. 61-260014 (Patent Document 2) discloses a polyacrylic resin having a water content of 20 to 80% by weight, a stoichiometric neutralization rate of 50 to 100%, and a weight average molecular weight of 1 × 10 ⁶ . By adding an aluminum salt and a polyhydric alcohol to an acid monovalent salt, the skeleton of the gel-like plaster body becomes tough, has excellent shape retention at high temperatures, has good water retention, and is good for the skin. technology that provides even adhesiveness becomes good base agent.

  Japanese Patent Application Laid-Open No. 06-135828 (Patent Document 3) discloses a 10% aqueous solution viscosity of 100 to 1000 cps as a transdermal absorption preparation having high adhesive strength and cohesive strength, excellent stability over time, and high skin safety. In addition, a solid or powdered polyacrylic acid as an essential component, a water-soluble polymer, a polyhydric alcohol, water, and a drug-containing one are disclosed.

Furthermore, Japanese Patent Laid-Open No. 10-237110 (Patent Document 4) discloses that when gelled, there are few insolubles, the neutralization rate is 40 to 60%, and the 0.2% viscosity is 500 to 800 mPa · s. It is exemplified that a certain polyacrylic acid partial neutralized product is excellent as a thickener for a spreading agent.
JP 58-021612 A (Claims) JP-A-61-260014 (Claims) Japanese Patent Laid-Open No. 06-135828 (Claims) JP-A-10-237110 (Claims)

The conditions required for the base or plaster used in the poultice are:
(1) No exudation of the plaster from the back surface of the nonwoven fabric or knitted fabric that is the support (2) Excellent water retention (3) Adhesion to the skin during use, peelability after use (4) excellent stability over time, (5) excellent safety, and (6) a uniform crosslinked state can be formed and can be mass-produced.

Those using polymer in the invention described in Patent Document 1 and Patent Document 2 is excellent in water retention as poultice, adhesion to the skin during use, but has an advantage in peeling property after use It is difficult to ensure sufficient adhesiveness during use.
In addition, attempts have been made to improve the adhesiveness by softening the plaster by adjusting the type of aluminum compound and the amount of the crosslinking agent. However, if the plaster is softened, bleeding and dripping of the plaster will occur. A problem arises, and it cannot be made into a plaster that satisfies the shape retention during production.

The invention described in Patent Document 3 improves the adhesive force by using powdered polyacrylic acid in combination with a polyacrylic acid partial neutralized product, but the stability over time of the plaster is insufficient, state changes to the state or gel-like plaster itself of the adhesive occurs over time, can cause the problem of strike through and sticky deterioration of plaster to the support, and yet fundamental solution It is not possible.

  Furthermore, when the partially neutralized polyacrylic acid described in Patent Document 4 is used as a base of a poultice, although the exudation of the poultice is good, it is difficult to obtain a plaster with good adhesion, and it is completely It cannot be said to be a thing.

In view of the present situation, the present invention has excellent water retention and formability, no exudation of the plaster to the support, excellent peelability despite excellent adhesiveness, stability over time and safety It is intended to provide a base and plaster for a cataplasm excellent in properties.
Furthermore, another object of the present invention, on the occasion in producing such high-performance poultice, a uniform crosslinked state, and base for cataplasm can dramatically improve productivity and It is intended to provide a plaster.

In order to solve the above problems, the invention according to claim 1 of the present invention is
Acrylic acid or methacrylic acid and their salts are the main constituent monomers,
A copolymer obtained by polymerizing a monomer mixture in which the constituent ratio of the acid and the salt is 50/50 to 60/40 in molar ratio ,
The viscosity of a 0.2% by mass aqueous solution at a temperature of 20 ° C. is 200 to 450 mPa · s , the unreacted monomer content is 5,000 ppm or less, measured by a method in accordance with the pharmaceutical additive regulations, and obtained by the following formula 1. A base for poultices , wherein the content of the low polymer is 5% by mass or less .

The invention according to claim 2 of the present invention is
In the base for poultice according to claim 1,
The copolymer is
The unreacted monomer content is 2,000 ppm or less, and the content of the low polymer is 3% by mass or less .

The invention according to claim 3 of the present invention is
In the base for poultice according to claim 1 or 2,
The viscosity of the 0.2 mass% aqueous solution of the copolymer at a temperature of 20 ° C. is
300 to 400 mPa · s.

The invention according to claim 4 of the present invention is
In the base for poultices in any one of Claims 1-3,
The copolymer is
It is prepared by photopolymerization.

The invention according to claim 5 of the present invention is
An acrylic acid or methacrylic acid and their salts principal constituent monomer,
Allocations of the acid and salt is composed of a copolymer and a polyvalent metal compound obtained by polymerizing a monomer mixture in a molar ratio of 50 / 50-60 / 40,
The copolymer has a viscosity of 200 to 450 mPa · s in a 0.2% by mass aqueous solution at a temperature of 20 ° C. , an unreacted monomer content of 5,000 ppm or less, and is measured by a method in accordance with the pharmaceutical additive regulations, It is a paste agent paste characterized by the content of the low polymer calculated | required by following Numerical formula 1 being 5 mass% or less .

The invention according to claim 6 of the present invention is
In the plaster paste according to claim 5,
The polyvalent metal compound is
It is an aluminum compound selected from aluminum sulfate, aluminum chloride, aluminum silicate, aluminum phosphate, aluminum hydroxide, and dihydroxyaluminum aminoacetate.

The invention according to claim 7 of the present invention is
In the plaster for cataplasm according to claim 5 or 6,
The plaster for cataplasms is
As a water retention agent, polyhydric alcohol is contained.

The invention according to claim 8 of the present invention provides
In the poultice paste according to claim 7,
The polyhydric alcohol is
It is characterized by being glycerin.

The added plaster of aluminum compound and a polyhydric alcohol in poultices for base and this base of the present invention, the copolymer constituting the base is selected from the group consisting of acrylic acid or methacrylic acid and main constituent single salts thereof A copolymer obtained by polymerizing a monomer mixture having a molar ratio of 50/50 to 60/40 as a constituent ratio of the acid and the salt, and 0.2 mass at a temperature of 20 ° C. Specific that the viscosity of the aqueous solution is 200 to 450 mPa · s, the unreacted monomer content is 5,000 ppm or less, and the content of the low polymer is 5% by mass or less, measured by a method in accordance with the pharmaceutical additive regulations. Since the main constituent requirement is that the copolymer has a partially neutralized poly (meth) acrylic acid structure, a well-balanced crosslinked structure is formed.
Therefore, in order to enable the preparation of a gel-like paste that is excellent in water retention, adhesiveness, and formability, without oozing out and sticking to the support, and excellent in stability over time, It is possible to prepare an excellent cataplasm having these characteristics.
In particular, since the content of unreacted monomer and low polymer contained in the copolymer is extremely small, the cataplasm using the cataplasm for cataplasm of this invention is highly safe. It also has.

Furthermore, since the base for poultices comprising a specific copolymer in the present invention has adhesiveness alone, it is not necessary to add a thickener or an adhesion-imparting agent when making a plaster.
Therefore, the adjustment time of the plaster can be shortened and the number of manufacturing steps can be reduced, and as a result, the productivity of the poultice can be dramatically improved.

Hereinafter, a poultice for bases and plaster of the present invention, that describes in detail by way of examples.
It should be noted that the present invention is not limited to these examples, and can be appropriately modified as long as the gist of the present invention is not changed.

The copolymer constituting the base for cataplasms of this invention has a structure in which a part of poly (meth) acrylic acid is neutralized with an alkali, and is water-soluble having a linear or branched molecular structure. copolymer der of Ru.
The main monomer constituting the copolymer is (meth) acrylic acid and a salt thereof, even after copolymerization using (meth) acrylic acid and a salt thereof, after polymerizing (meth) acrylic acid, It can also be obtained by partially neutralizing this.

At that time, a copolymer obtained by copolymerizing other monomers can be effectively used as a base of the present invention within a range not inhibiting the intended effect of the present invention.
Examples of such monomers include unsaturated carboxylic acids represented by maleic acid, itaconic acid, fumaric acid, and derivatives thereof, 2-acrylamido-2-methylpropanesulfonic acid, (meth) allylsulfonic acid, styrenesulfone. Examples thereof include unsaturated sulfonic acids such as acids and derivatives thereof.
If necessary, one or more of these can be added within a range of 10 mol% or less based on the total amount of (meth) acrylic acid and (meth) acrylate.

In view of basic performance as a poultice, such as water retention, adhesion to the skin during use, and peelability after use, a copolymer of (meth) acrylic acid and (meth) acrylate is preferred, and acrylic Most preferred are acids and acrylate copolymers.
Examples of the salt include alkali metal salts and ammonium salts, but sodium salts are preferred for the present invention.

The polymerization method for obtaining the copolymer of the present invention, the aqueous solution polymerization method, slurry polymerization method, reversed-phase suspension polymerization method, such as emulsion polymerization method, Ru include various known radical polymerization method.
In view of solvent removal, solvent safety, surfactant incorporation, etc., it is desirable to use an aqueous solution polymerization method.

In the aqueous solution polymerization method, for example, an aqueous solution of a polymerizable monomer such as (meth) acrylic acid or (meth) acrylate is adjusted to a predetermined concentration, and dissolved oxygen in the reaction system is sufficiently filled with an inert gas. After substitution, a radical polymerization initiator is added, and if necessary, the polymerization reaction is carried out by appropriately heating or irradiating light (ultraviolet rays).

When performing heating the polymerization reaction, relatively weak thermal polymerization initiator thermal decomposition to heat, for a method of polymerizing the resulting radicals as an initiator, a low polymer or a gel product, residual monomer Reduction cannot be expected much.
On the other hand, the polymerization reaction by irradiation with light (ultraviolet rays) is a method in which a photopolymerization initiator is excited by light (ultraviolet rays) to be radicalized, and the resulting radical is used as a initiator for the polymerization reaction. It is possible, the reaction progress rate is also good, low polymer and gel can be reduced, and this is the preferred method for this invention.

When light (ultraviolet) irradiation is performed and (meth) acrylic acid and (meth) acrylate in the aqueous solution are copolymerized, the aqueous solution increases in viscosity as the polymerization reaction proceeds, and the polymerization reaction is completed. Sometimes it becomes a hydrous gel.
The obtained water-containing gel-like product is cut and then dried by hot air, reduced pressure, indirect heating or various drying methods in combination thereof, and further pulverized to obtain a powdery polymer.

In addition, when the copolymer is used as a plaster after being crosslinked with a crosslinking agent as a base for a poultice, the (meth) acrylic acid constituting the copolymer is 50 mol% or less of the copolymer. The gel-like plaster after crosslinking becomes hard and sufficient adhesive strength cannot be obtained unless the amount of the crosslinking agent is significantly reduced.
However, if the amount of the cross-linking agent is reduced, productivity is lowered because a longer curing time must be taken.
On the other hand, when the molar ratio of the constituent monomer (meth) acrylic acid exceeds 60 mol% of the copolymer, the gel-like paste after crosslinking becomes soft and the adhesiveness is improved. Exudation from the water tends to occur.

Therefore, the constituent amount of (meth) acrylic acid constituting the copolymer must be in the range of 50 to 60 mol% in the copolymer.
When a monomer other than (meth) acrylic acid and (meth) acrylate is used as a constituent monomer contained in this copolymer, the amount of the constituent monomer used is the copolymer. It is preferable that it is 10 mol% or less of the total monomer which comprises.
Even in such a case, the constituent ratio of (meth) acrylic acid and its salt needs to be 50/50 to 60/40 mol% of (meth) acrylic acid: (meth) acrylate.

Moreover, when the viscosity of the 0.2 mass% aqueous solution of the copolymer is higher than 450 mPa · s at a temperature of 20 ° C., the solubility and dispersibility deteriorate.
Therefore, since the crosslinking speed becomes slow and a uniform crosslinked state cannot be obtained, the resulting plaster has variations in properties, making it difficult to prepare a cataplasm excellent in adhesiveness and formability. Pap that breaks the balance between adhesiveness and base strength required for cross-linkable cataplasms, making it difficult to apply the resulting cataplasm to the skin, and also causes plaster residue and stringing on the skin. Will form an agent.
Furthermore, since the curing rate of the gel-like paste is also slowed down, it takes time to cure the gel-like paste, which is the rate-limiting step in the production of the poultice.
That is, the productivity of the cataplasm is remarkably lowered by the delay of the curing rate.

  If the viscosity of the 0.2 mass% aqueous solution is a paste using a copolymer having a viscosity of less than 200 mPa · s at a temperature of 20 ° C., the cohesive force of the gel-like paste decreases, and the paste remains on the skin. A stringing phenomenon may occur, and the exudation of the plaster tends to occur from the back surface of the nonwoven fabric, woven or knitted fabric that is the support.

Therefore, in this invention, the copolymer used for the base for poultices has a viscosity of 0.2% by mass aqueous solution at a temperature of 20 ° C. in the range of 200 to 450 mPa · s, preferably 300 to It has a viscosity of 400 mPa · s.
If a copolymer having such a viscosity is used as a base of a poultice, the productivity of the poultice can be remarkably improved.

Further, as the copolymer of this invention, the amount of unreacted monomer remaining in the copolymer, the following 5,000 ppm, preferably those of the following 3,000 ppm, more preferably 2 , it is the following 000ppm.
When the unreacted monomer contained in the copolymer exceeds 5,000 ppm, the skin to which the poultice made of a gel-like paste using the copolymer is attached is likely to be inflamed.
Incidentally, the partially neutralized polyacrylic acid having a residual monomer amount exceeding 5,000 ppm is obtained by known techniques, that is, post-polymerization or post-treatment after polymerization, that is, addition of a polymerization initiator, heating of the polymer, etc. The residual monomer amount can be 5,000 ppm or less.

As the copolymer of the present invention, when the content of the low polymer measured by a method in accordance with the “Pharmaceutical Additives Standard” exceeds 5% by mass, the cohesive strength of the gel plaster decreases, and the skin The remaining plaster and the stringing phenomenon occur, and the exudation of the plaster from the back surface of the nonwoven fabric or knitted fabric as the support tends to occur.
Therefore, the content of the low polymer contained in the copolymer needs to be 5% by mass or less , more preferably 3% by mass or less.
The copolymer having a low polymer content of 5% by mass or less can be obtained by known techniques such as photopolymerization and post-treatment after polymerization, that is, washing and classification.

The copolymer obtained as described above is excellent as a base for a poultice, and against this base, water, a polyvalent metal compound as a crosslinking agent, and further a polyvalent as a water retention agent. Alcohol is mix | blended and it can be mixed and it can be set as a gel-like paste.
It should be noted that the plaster body of the present invention can of course contain additives such as inorganic powder and medicinal ingredients in addition to the above essential components, and each component is predetermined. It is obtained by kneading after adding or mixing all at once or so as to achieve a blending ratio of

  As a blending ratio when preparing a gel-like plaster using the base for a poultice comprising the copolymer of the present invention, the base for a poultice comprising a copolymer is usually used with respect to the total amount of the plaster. 5 to 20% by weight of an agent, 1 to 50% by weight of a water retention agent such as glycerin, 0.001 to 2% by weight of a polyvalent metal compound such as aluminum hydroxide, 1 to 10% by weight of an inorganic additive such as kaolin, a medicinal component They are 0.01-10 mass% and water | moisture content 30-80 mass%.

If this base for poultices is less than 5% by mass relative to the total amount of the plaster, the tackiness, thickening and formability will decrease, and if it exceeds 20% by mass , it will become too thick and difficult to knead. Kneading is impossible.
Therefore, it is usually 5 to 20% by mass, preferably 7 to 12% by mass.

The polyvalent metal compound used in preparing the plaster functions as a crosslinking agent.
Specifically, aluminum compounds represented by dihydroxyaluminum aminoacetate, aluminum hydroxide, aluminum chloride, aluminum sulfate, aluminum silicate, aluminum phosphate, aluminum hydroxide / magnesium, aluminum glycinate, calcium chloride, sulfuric acid The compound is not particularly limited as long as it is a compound containing a metal having a valence of 2 or more, such as diiron (polyvalent metal compound), but among the polyvalent metal compounds described above, an aluminum compound is preferable.
These polyvalent metal compounds may be used alone or in combination, and may be used regardless of whether they are water-soluble or hydrophobic.

The blending amount of the polyvalent metal compound varies depending on the degree of polymerization and blending amount of the copolymer, the type of the polyvalent metal compound and other blends, but is usually 0.001 based on the total amount of the plaster. -2 mass% is preferable, More preferably, it is 0.01-1 mass%.

  When preparing a cataplasm using the cataplasm base or paste according to the present invention, in addition to the above components, additives generally used for external preparations, that is, improving the suitability during production and the quality during use For this purpose, water-soluble polymers such as gelatin, polyvinyl alcohol, sodium carboxymethylcellulose, glycerin, polyvinylpyrrolidone, sodium alginate and the like may be blended as a thickener or a tackifier.

Moreover, polyhydric alcohols such as glycerin, propylene glycol, sorbitol and butylene glycol can be used as the water retention agent.
However, when using substances that are harmful to the human body, such as ethylene glycol, special care must be taken.
Furthermore, kaolin, titanium oxide, silicic anhydride and the like can be used as powder inorganic fillers, dibutylhydroxytoluene, butylhydroxyanisole and the like as antioxidants, methyl paraoxybenzoate, propyl paraoxybenzoate and the like as preservatives, If necessary, one or more kinds can be blended in the plaster.

The formulated into poultices, specific examples of other medicinal ingredient, for example, methyl salicylate, glycol salicylate, menthol, camphor, thymol, mint oil, Boruoneru, antihistamines such as glycyrrhizic acid, indomethacin, flurbiprofen, etc. Anti-inflammatory analgesics, local anesthetics such as dibucaine hydrochloride, lidocaine, etc., but are not limited to these, natural products having medicinal ingredients that can be used as a transdermal drug for clinical or research purposes If it is a synthetic chemical or the like, there is no particular limitation.
These may be used alone or in combination of two or more, if necessary, and the blending amount of such medicinal ingredients is usually preferably 0.1 to 10% by mass with respect to the total amount of the paste.

The poultice is completed by coating and spreading the gel-like plaster prepared as described above on a support surface such as a non-woven fabric, and then cutting and packaging the coated surface covered with a peelable film. The

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
In addition, physical property test methods used in Examples and Comparative Examples are also described.

<Example 1>
Preparation of copolymer (A-1) In a stainless steel reaction vessel, the monomer concentration is 30% by mass, the total amount is 1 kg, and the composition of acrylic acid and sodium acrylate is 60 mol% and 40 mol%, respectively. In addition, an aqueous acrylic acid solution, an aqueous sodium acrylate solution, and ion-exchanged water were charged, and the mixture was stirred while introducing nitrogen gas into the reaction system, and deaerated.
Next, 900 ppm of 2,2′-azobis (2-methylpropionamidine) dihydrochloride as a polymerization initiator for the total charged monomers (total amount of acrylic acid and sodium acrylate), and chain transfer 10 ppm of 2-mercaptoethanol was added as an agent.
Subsequently, a polymerization reaction was performed for 60 minutes at room temperature while continuously irradiating UV light having a wavelength of 300 to 450 nm to obtain a gel polymer.
The gel-like polymer taken out from the reaction vessel was put into a small chopper and shredded into minced meat, and then dried with hot air at a temperature of 120 ° C. for 5 hours.
The obtained dried product was pulverized to obtain a powdery copolymer (A-1) serving as a base for cataplasms of the present invention.

<Example 2>
Preparation of copolymer (A-2) All the same as Example 1 except that the charged molar ratio of acrylic acid and sodium acrylate in the preparation of copolymer (A-1) was changed to 51/49. The operation was performed to obtain a copolymer (A-2) which is a base for cataplasms of the present invention.

<Example 3>
Preparation of copolymer (A-3) In a reaction vessel, the monomer concentration was 30% by mass, the total amount was 1 kg, and the compositions of acrylic acid, sodium acrylate, and methacrylic acid were 58 mol%, 40 mol%, and 2 mol, respectively. The same procedure as in Example 1 was carried out except that an acrylic acid aqueous solution, sodium acrylate, and a methacrylic acid aqueous solution were prepared so as to be a mol%. A-3) was obtained.

<Example 4>
Preparation of copolymer (A-4) In a stainless steel dewar, acrylic acid and sodium acrylate are 60 mol% and 40 mol%, respectively, and the total amount is 1 kg and the monomer concentration is 30 mass%. Ion exchange water was added as follows.
After adjusting the temperature of the aqueous monomer solution to 10 ° C., nitrogen was introduced and deaerated for 60 minutes.
Next, with respect to the total charged monomers, as a polymerization initiator, azo-bis-amidinopropane hydrochloride 500 ppm, t-butyl Le hydroperoxide 100 ppm, 200 ppm sodium persulfate, and sodium erythorbate 150ppm added Then, after 8 hours, the gel-like polymer obtained after the completion of the polymerization was taken out, put into a small chopper, and shredded into ground meat.
The obtained chopped gel is dried in a hot air dryer at a temperature of 100 ° C. for 5 hours, and the dried product is pulverized to form a powdery copolymer (A-4) that serves as a base for cataplasms of the present invention. Got.

<Comparative Example 1>
Preparation of copolymer (A-5) The composition of the monomer in Example 4 was changed except that acrylic acid and sodium acrylate were added to 45 mol% and 55 mol%, respectively, and 2-mercaptoethanol was added to 200 ppm. In the same manner as in Example 4, a powdery copolymer (A-5) was obtained.

<Comparative example 2>
The amount of the polymerization initiator in the preparation example 4 of the copolymer (A-6), 40ppm a t- butyl Le hydroperoxide, except that sodium persulfate was changed 200 ppm, the sodium erythorbate to 40ppm, the embodiment In the same manner as in No. 4, a powdery copolymer (A-6) was obtained.

  Physical properties (viscosity, pH, unreacted monomer content, low polymer content, and amount of gel material) of the six types of copolymers (A-1 to A-6) obtained as described above. ) Was measured by the following method, and the results are shown in Table 1.

<Viscosity>
Put 400 g of pure water in a 500 ml conical beaker, add 0.8 g of accurately weighed copolymer while stirring with a magnetic stirrer, and stir for 1 hour to prepare a 0.2% by weight aqueous copolymer solution. The viscosity at a temperature of 20 ° C. was measured with a Brookfield viscometer (rotor number: No. 2, rotation speed: 30 rpm, measurement time: after 90 seconds).

<PH>
The pH when 0.2 g of the copolymer was dissolved in 100 ml of pure water was measured.

<Unreacted monomer content>
The copolymer is dissolved in pure water to prepare a 1.0% by weight concentration (solid content conversion) aqueous copolymer solution, and 2 g of this aqueous copolymer solution is poured into 20 ml of methanol and stirred for 30 minutes. To precipitate the copolymer. After 30 minutes, the supernatant was collected and the residual monomer was measured by high performance liquid chromatography.
Column: Hitachi HPLC packed column # 3056, eluent: 0.1% phosphate buffer, detector: UV 195 nm

<Low polymer content>
The glass filter (G4) is dried in advance at a temperature of 105 ° C. for 30 minutes, allowed to cool in a desiccator, and then weighed accurately.
Next, about 2 g of the copolymer was accurately weighed, 200 ml of pure water was added, and it was occasionally shaken to dissolve, then 50 ml of hydrochloric acid was added while stirring this solution, and the mixture was heated at about 40 ° C. for 30 minutes while stirring. It was left at a temperature of 20 ° C. for 24 hours.
Filter this solution, add 1 drop of Phenophthalphthalein reagent to the filtrate, add sodium hydroxide solution (2 → 5) until the solution turns a faint red color, and then add diluted hydrochloric acid (1 → 30) dropwise. And
Adjust the pH to 8.0-8.3.
Next, 200 ml of pure water is added, and 25 ml of calcium chloride reagent solution is added dropwise while stirring vigorously, followed by heating at a temperature of about 40 ° C. for 30 minutes while stirring vigorously. This liquid was suction filtered using the previous glass filtration, the residue was washed with 10 ml of pure water three times, dried at a temperature of 105 ° C. for 3 hours, allowed to cool in a desiccator, and its mass was accurately measured. The amount of the low polymer was obtained from the following formula.

<Gel material>
400 g of pure water was put into a 500 ml conical beaker, and 0.8 g of the copolymer was added while stirring with a magnetic stirrer, followed by stirring for 1 hour.
Next, stirring was stopped and the mixture was left at a temperature of 20 ° C. for 24 hours. Thereafter, the prepared liquid re-stirred for 1 hour was put on a 140 mesh JIS standard sieve (mesh opening 106 μm), and the amount (ml) of the gel remaining on the sieve was measured.

<Examples 5-11 and Comparative Examples 3-6>
Six types of copolymers (A-1 to A-6) obtained as described above and a commercially available 20% by weight aqueous solution of polyacrylic acid (“Jurimer AC-10H” manufactured by Nippon Pure Chemical Co., Ltd.) A paste was prepared as follows using B-1) and the properties thereof were measured.

Preparation and evaluation of plaster After following the formulation shown in Table 2, uniformly blend glycerin with copolymer, aluminum hydroxide, dihydroxyaluminum aminoacetate and titanium oxide, and then add water with tartaric acid dissolved in advance. The mixture was stirred and kneaded to obtain a plaster.
After applying and spreading this plaster on a polyester non-woven fabric (Nippon Vilene Co., Ltd. patch base fabric), a polypropylene film was pasted on the coated surface and cut into a predetermined size to obtain a test piece. The performance evaluation shown was performed and the results are summarized in Table 2.

<Hardness>
The plaster was filled in a petri dish so as to have a constant thickness, and the hardness after 30 days from the production was measured with a rheometer.
Measurement conditions Measurement speed: 60 mm / min Measurement depth: 2 mm
Adapter: Bakelite

<Adhesiveness>
A test piece 30 days after the production was pasted on an adherend (bakelite), and the roller (load 60 g) was reciprocated once to cause pressure bonding.
The 90-degree peel strength one day after the pressure bonding was measured with a tensile tester in accordance with JIS Z 0237.

<About probe tack>
The adhesive force when a circular probe was brought into contact with a test piece 30 days after the production was measured with a probe tack measuring device.
Measurement conditions Probe diameter: 5mm
Contact speed and peeling speed: 10 mm / second Contact load: 0.98 N / cm ²
Contact time: 1 second

<About bleeding>
The presence or absence of the exudation of the test piece on the non-woven fabric 30 days after the production was visually evaluated in four stages as follows.
◎: No oozing ○: Almost no oozing △: With oozing ×: With oozing

As is apparent from Table 2, the pastes of Comparative Examples 3 to 6 had hardness and relatively good shapeability, but exuded and the paste properties were unstable.
On the other hand, the pastes of Examples 5 to 11 had high adhesive strength, had formability, and had excellent performance with no back bleeding, and were optimal as plasters for poultices.

The base for a poultice according to the present invention has excellent adhesive strength (adhesive strength) and peelability when formed into a plaster , has extremely low exudability, and extremely high productivity. It can be suitably used as a base and is highly likely to be widely used in the cataplasm industry.

Claims (8)

Acrylic acid or methacrylic acid and their salts as main constituent monomers,
A copolymer obtained by polymerizing a monomer mixture in which the constituent ratio of the acid and the salt is 50/50 to 60/40 in molar ratio,
The viscosity of a 0.2 mass% aqueous solution at a temperature of 20 ° C. is 200 to 450 mPa · s,
Unreacted monomer content is 5,000 ppm or less,
A base for poultices, characterized in that the content of the low polymer obtained by the following formula 1 is 5% by mass or less as measured by a method based on the pharmaceutical additive regulations.

The copolymer is
The base for cataplasms according to claim 1, wherein the content of unreacted monomer is 2,000 ppm or less, and the content of low polymer is 3% by mass or less. The viscosity of the 0.2 mass% aqueous solution of the copolymer at a temperature of 20 ° C. is
It is 300-400 mPa * s, The base for cataplasms of Claim 1 or 2 characterized by the above-mentioned. The copolymer is
The base for poultice according to any one of claims 1 to 3, wherein the base is prepared by photopolymerization. Acrylic acid or methacrylic acid and their salts are the main constituent monomers,
The composition ratio of the acid and salt is composed of a copolymer obtained by polymerizing a monomer mixture consisting of 50/50 to 60/40 in molar ratio and a polyvalent metal compound,
The copolymer is
The viscosity of a 0.2 mass% aqueous solution at a temperature of 20 ° C. is 200 to 450 mPa · s,
Unreacted monomer content is 5,000 ppm or less,
An ointment for cataplasms characterized in that the content of the low polymer obtained by the following formula 1 is 5% by mass or less as measured by a method in accordance with the pharmaceutical additive regulations.

The polyvalent metal compound is
The plaster for cataplasm according to claim 5, which is an aluminum compound selected from aluminum sulfate, aluminum chloride, aluminum silicate, aluminum phosphate, aluminum hydroxide, and dihydroxyaluminum aminoacetate. The plaster for cataplasms is
The plaster for cataplasm according to claim 5 or 6, characterized in that it contains a polyhydric alcohol as a water retention agent. The polyhydric alcohol is
It is glycerin, The plaster for cataplasms of Claim 7 characterized by the above-mentioned.