JP2003129013A - Method for producing adhesive sheet and medical adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical adhesive sheet which hardly causes the stuffiness even after the long-time application by using materials which are not so expensive such as polyurethane, and by using materials and methods which are ecologically friendly, that is, without using chlorine-containing materials, phthalic acid-based plasticizers and organic solvents as mush as possible. SOLUTION: An aqueous medium emulsion in which polymer particles having different particle diameters are blended is applied to a release paper without using an emulsifier and a laminated film is formed in which a settlement velocities of the particles are different according to the diameters, and an adhesive layer and a non-adhesive support layer are dissociated in the thickness direction of a sheet. The addition of a salt such as sodium sulfate can control the velocities and make the film porous. As a consequence, the medical adhesive sheet which hardly causes the stuffiness even after the long-time application can be provided, since the permeability as the whole adhesive sheet can be raised.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an adhesive sheet comprising an adhesive layer and a support layer, and a patch for medical use produced by the method, for example, a first aid bandage, a dressing material, and a wound protectant. The present invention relates to an adhesive article (hereinafter, referred to as “medical adhesive sheet”) that is used for such purposes as above, and is particularly suitable when application for a long period of time is required and skin irritation due to swelling is a concern.

[0002]

2. Description of the Related Art Among medical adhesive sheets, general first-aid bandages and dressing materials are produced by applying an adhesive on release paper, drying the solvent in the adhesive, and then laminating a support such as a film. To do. For a bandage plaster or the like, a pressure-sensitive adhesive is directly applied onto a support and dried to obtain a bandage plaster. As described above, the adhesive and the support are used separately. Here, most of the pressure-sensitive adhesives used are solvent-based, and the solvent is volatilized by coating and drying, which may cause a burden on the environment.

As a film for a support in a first-aid bandage, a band-aid bandage, etc., a number of films containing a plasticized polyvinyl chloride as a main component, which are produced by a calendering method or a casting method, have been used. Since such a film has low moisture permeability, holes are punched or the like in order to prevent the occurrence of unevenness during application to the skin. As a support such as a dressing material,
In order to prevent the sticking during sticking, a polyurethane-based film or the like in which the resin itself has moisture permeability is widely used.

[0004]

However, in recent years, with respect to the use of the plasticized polyvinyl chloride, countermeasures have been demanded from the viewpoint of environmental problems due to the phthalic acid liquid plasticizer used and chlorine contained therein. There is. On the other hand, the polyurethane film is also expensive in price, and the dressing material is mainly used. Further, there is a polyolefin-based film as an alternative to the polyurethane-based film, but since it does not have moisture permeability as much as the polyurethane-based film, the unevenness at the time of sticking has not been solved. In recent years, the use of organic solvents has tended to be avoided due to environmental considerations.

In view of the above situation, the present invention uses an environment-friendly material / construction method, that is, a material containing chlorine, a phthalic acid plasticizer, and an organic solvent as little as possible, and is less expensive than polyurethane. The purpose of the present invention is to provide a pressure-sensitive adhesive sheet, especially a medical pressure-sensitive adhesive sheet, in which the sticking does not easily occur even when it is applied for a long time.

[0006]

Therefore, the present inventors have
As a result of intensive studies, when an aqueous emulsion containing different types of polymer particles was applied onto release paper, the different types of particles did not fuse in a homogeneously mixed state, but due to the difference in sedimentation speed of different types of particles, the same type of particles It was found that they form a laminated structure film in which they are gathered together. Further, they have also found that by controlling the cohesiveness of particles and the like, it is possible to generate voids in the film and to provide porosity. The following inventions have been completed based on those findings.

(1) Adhesive polymer particles,
An emulsion containing non-tacky polymer particles is applied to form a layer having tackiness (adhesive layer) on one side in the thickness direction of the sheet and a layer having no tackiness on the other side (support layer). ) Is formed, the manufacturing method of the adhesive sheet. (2) One of the two types of polymer particles has a larger sedimentation rate in the emulsion than the other, and a pressure-sensitive adhesive layer is provided on one side in the thickness direction of the sheet.
The method for producing a pressure-sensitive adhesive sheet according to (1), wherein a support layer is formed on one side facing each other. (3) The method for producing a pressure-sensitive adhesive sheet according to (2), wherein the sedimentation rate of the polymer particles having a higher sedimentation rate in the emulsion is twice or more the sedimentation rate of the polymer particles having a smaller sedimentation rate. (4) Polymer particles in which one of the two types of polymer particles has a larger sedimentation rate in the emulsion than the other, and one of the two types of polymer particles has a larger average particle size in the emulsion than the other The method for producing a pressure-sensitive adhesive sheet according to any one of (2) and (3), wherein (5) The method for producing a pressure-sensitive adhesive sheet according to (4), wherein the average particle size of the polymer particles having a larger average particle size in the emulsion is 2 to 100 times that of the polymer particles having a smaller average particle size. (6) The difference between the average particle sizes of the two types of polymer particles in the emulsion is 100 to 5000 nm,
The method for producing a pressure-sensitive adhesive sheet according to any one of (4) and (5). (7) The method for producing a pressure-sensitive adhesive sheet according to any one of (1) to (6), wherein the two types of polymer particles are acrylic polymer particles. (8) The method for producing a pressure-sensitive adhesive sheet according to any one of (1) to (7), wherein the emulsion is an aqueous emulsion containing no emulsifier. (9) The emulsion according to any one of (1) to (8), wherein the emulsion contains at least one salt selected from the group consisting of sodium sulfate, sodium chloride, sodium nitrate, and sodium phosphate. Of the pressure-sensitive adhesive sheet according to claim 1. (10) A medical pressure-sensitive adhesive sheet produced by the method according to any one of (1) to (9). (11) The porosity of the support layer is 5% or more, (1
The medical adhesive sheet according to 0). (12) The medical pressure-sensitive adhesive sheet according to (10) or (11), which has a water vapor permeability of 1000 g · 24 h / m ² or more.

That is, the present invention is characterized in that the porous support layer and the pressure-sensitive adhesive layer can be produced in one step. Specifically, one side of the laminated sheet can be prepared as a laminated pressure-sensitive adhesive sheet having a porous film having no tackiness and the other side having a film having tackiness. Moreover, since the porous support layer and the pressure-sensitive adhesive layer can be manufactured by the manufacturing method according to the present invention, the moisture permeability of the pressure-sensitive adhesive sheet as a whole can be improved without depending on the moisture permeability of the material itself. Therefore, the choice of materials for the adhesive layer and the support layer is expanded,
An environment-friendly and inexpensive material (for example, acrylic polymer particles) can be selected.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A medical pressure-sensitive adhesive sheet according to the present invention will be described with reference to FIG. 1 (an explanatory view of a method for producing a pressure-sensitive adhesive sheet according to the present invention). However, the present invention is not limited to the embodiments shown in the drawings.

The medical pressure-sensitive adhesive sheet according to the present invention is a sheet produced by blending different aqueous emulsions prepared in a system without an emulsifier and then utilizing the difference in the sedimentation speed of polymer particles of each emulsion ( Figure 1 (c)
Structure). Here, an emulsion means a system in which droplets are dispersed in another liquid that does not dissolve it. The medical pressure-sensitive adhesive sheet according to the present invention is separated into at least two layers, and one layer is made of a non-tacky polymer (“tack-free polymer particles” shown by 3 in the figure as an integrated body. Polymer) as a main component, and the remaining one layer contains a polymer having adhesiveness that plays a role of an adhesive (a polymer in which “adhesive polymer particles” shown by 4 in the figure are integrated).

In the present specification, "adhesiveness" means the adhesive strength to a phenol resin plate measured by a tensile test at a tensile speed of 300 mm / min.
A specific measuring method will be described later (paragraph “0038”). Having tackiness means that the tackiness is 1 N / 20 mm or more, and does not have tackiness (also referred to as non-tackiness).
Means that the adhesive force is less than 1 N / 20 mm.

The production method according to the present invention does not limit the material of the polymer particles used.
Although conventionally used polymer particles can be used, it is preferable to use acrylic polymer particles for both the tack-free polymer particles 3 and the tacky polymer particles 4 from the viewpoint of consideration for the environment and cost. The acrylic polymer particles preferably have 1 to 1 carbon atoms.
8, and more preferably, a homopolymer of (meth) acrylic acid alkyl ester having an alkyl group having 2 to 12 carbon atoms or a copolymer thereof.

As the above-mentioned (meth) acrylic acid alkyl ester, ethyl ester, propyl ester, butyl ester, hexyl ester, octyl ester, 2-
Examples thereof include ethylhexyl ester, nonyl ester, decyl ester, lauryl ester and stearyl ester. These ester chains may be linear or branched.

The tack-free polymer particle 3 is not particularly limited as long as it is a combination of the above-mentioned monomers having a high glass transition point (Tg), and a combination of acrylic acid ethyl ester and methacrylic acid methyl ester is particularly preferable.

The emulsion of the adhesive polymer particles 4 is
Not only the above-mentioned homopolymers and copolymers but also 1 to 50% by weight of other monomers (described below) copolymerizable with the (meth) acrylic acid alkyl ester as a main component and copolymerizable with the monomers,
Preferably, various copolymers obtained by copolymerizing in the range of 3 to 40% by weight are used.

Examples of the above-mentioned monomer copolymerizable with the (meth) acrylic acid alkyl ester include carboxyl group-containing unsaturated monomers such as (meth) acrylic acid, maleic acid, fumaric acid and crotonic acid, and (meth ) Acrylic acid-2-hydroxyethyl ester and other (meth) acrylic acid hydroxyalkyl ester, (meth) acrylamide and dimethyl (meth) acrylamide and its derivatives, and N-butoxymethyl (meth) acrylamide and the like (Meth) acrylic acid-N, N such as N-alkoxyalkyl (meth) acrylamide, (meth) acrylic acid-N, N-dimethylaminoethyl ester
Functional monomers such as acid amide group-containing unsaturated monomers such as -alkylaminoalkyl esters and N-vinylpyrrolidone are mentioned. In addition to these functional monomers, non-functional monomers such as vinyl acetate, styrene, acrylonitrile, etc. can coexist.

Specific tacky polymer particles 4 are:
From the viewpoint that the moisture permeability of the polymer particles themselves becomes high, a copolymer of an acrylic acid alkyl ester, an acrylic acid alkoxyalkyl ester and acrylic acid which imparts tackiness is preferable. Particularly, a terpolymer of acrylic acid-2-ethylhexyl ester, acrylic acid-2-methoxyethyl ester and acrylic acid is preferable because of good balance of tackiness and moisture permeability.

In producing an emulsion containing the above-mentioned polymer particles, when a polymerization reaction is carried out using an emulsifier as in the case of producing a conventional pressure-sensitive adhesive sheet, it is used as a medical pressure-sensitive adhesive sheet when applied to the skin. Water resistance and sweat resistance are poor due to the effect of the emulsifier. Therefore, the emulsion used in the present invention is preferably prepared by an emulsifier-free polymerization method without using an emulsifier. When the emulsifier-free polymerization is difficult, a polymer emulsifier or a polymer dispersant may be used as long as the water resistance and the sweat resistance are not seriously affected.

As the release paper represented by 1 in the figure, one normally used in the art can be used. As an example, there may be mentioned a release paper having a release property imparted by a silicone treatment or the like, but other materials may be used. Further, the shape such as thickness is not particularly limited.

The method for producing the pressure-sensitive adhesive sheet according to the present invention will be described below. First, the emulsion of tack-free polymer particles 3 and the emulsion of tacky polymer particles 4 are blended. Next, the blended solution was cast on a release paper whose both sides were given release properties by silicone treatment or the like.
Get the structure of. After that, by evaporating the water,
A pressure-sensitive adhesive sheet in which a support layer composed of the tack-free polymer particles 3 and a pressure-sensitive adhesive layer composed of the tacky polymer particles 4 are laminated is obtained (FIG. 1 (c)).

In the blend of the emulsion of the tack-free polymer particles 3 and the emulsion of the tacky polymer particles 4, it is preferable to adjust the solid content ratio of each polymer particle according to the thickness of each finished layer. Specifically, the tack-free support layer has a thickness of 10 to 100 μm, preferably 2
The thickness of the pressure-sensitive adhesive layer is 0 to 80 μm, and the pressure-sensitive adhesive layer is 20 to 100 μm, preferably 30 to 60 μm. If both layers are too thick, it becomes difficult to volatilize water as a solvent. On the other hand, if the thickness of both layers is too thin, the strength and adhesive strength of the sheet will be insufficient, resulting in poor practicability.

The emulsion coated on the release paper as shown in FIG. 1 (a) is separated as shown in FIG. 1 (b) and then as shown in FIG. 1 (c) due to the difference in sedimentation speed of each polymer particle.
That is, those with a high sedimentation rate settle in the lower layer, and those with a low sedimentation rate gather in the upper layer. In the present invention, by utilizing this property, the support layer containing the tack-free polymer particles 3 as the main component and the adhesive layer containing the tacky polymer particles 4 as the main component are produced simultaneously and separately. You can Which of the adhesive polymer particles 4 and the tack-free polymer particles 3 is laminated on the release paper side can be freely set according to the purpose of the final product.

Here, the sedimentation rate is the volume fraction of the transparent layer appearing in the upper layer portion as the particles settle, after the emulsion containing each polymer particle is placed in a predetermined container (test tube etc.) and allowed to stand. Can be quantified by measuring In the practice of the present invention, from the viewpoint that the layer of the tacky polymer particles 4 and the layer of the tack-free polymer particles 3 can be easily separated, it is desirable that the difference in the sedimentation speed of both polymer particles is large, and in particular, the sedimentation speed It is preferable that the sedimentation rate of the polymer particles having a large sedimentation rate is twice or more the sedimentation rate of the polymer particles having a small sedimentation rate. As means for controlling the sedimentation rate of polymer particles, there are methods such as using polymer particles having different particle diameters, polymer particles having different specific gravities, and polymer particles having different dispersion stability to an electrolyte, but the operation is simple. In terms of high versatility, it is preferable to control the sedimentation rate of polymer particles by using polymer particles having different particle diameters. Hereinafter, the particle size of the polymer particles will be described in detail.

With respect to the particle size of the polymer particles in the emulsion, the average particle size of the polymer particles settled and laminated on the side of the release paper is preferably 300 to 5000 nm, more preferably 400 to 2000 nm, facing the side of the release paper. The average particle size of the polymer particles laminated on the side is preferably 1 to 200 nm. Therefore, the difference between the average particle sizes of the two types of polymer particles is preferably about 100 to 500.
It is 0 nm. The average particle diameter of the polymer particles having a large average particle diameter is preferably 2 to 100 times the average particle diameter of the polymer particles having a small average particle diameter. Here, the particle size of the polymer particles in the emulsion, refers to the diameter of the sphere of the same volume as the polymer particles, if the polymer particles are aggregated in the emulsion, refers to the particle size of the aggregated particles . The average particle size of the polymer particles in the emulsion can be measured, for example, by the dynamic light scattering method.

Further, in order to control the particle size and to accelerate the sedimentation speed, the emulsion storage is made to have low storage stability and cohesiveness is accelerated, so that the emulsion is treated with sodium sulfate, sodium chloride, sodium nitrate and phosphoric acid. A salt such as sodium can be added. As for the amount of addition, it is preferable to set the critical coagulation concentration to the upper limit in the case of emulsion blending. When the concentration exceeds the critical coagulation concentration, the emulsion to be settled rapidly agglomerates, and it is difficult to form a target tack-free support layer and a pressure-sensitive adhesive sheet.

In the production method according to the present invention, the polymer particles in the emulsion are aggregated to a certain size, and they are allowed to settle to form a film. It will remain and will be formed as a porous sheet. This corresponds to imparting moisture permeability, which is advantageous as a medical adhesive sheet. That is, in the present invention, it becomes possible to realize the porosity of the support layer and the development of the tackiness in one step.

Here, the case where the support layer is porous means, for example,
For example, when observing with a microscope etc.,
It means that the ratio is 5% or more (volume basis). Also,
A medical adhesive sheet having moisture permeability means that the sheet is permeable to moisture.
It means that the humidity is high. Here, the moisture vapor transmission rate
At a specified time in a system in which a cup containing distilled water is covered with a test piece
The amount of weight loss after a lapse of time, the specific measuring method will be described later
(Paragraph “0040”). As a medical adhesive sheet
Is 1000g ・ 24h / m by this measuring method ²that's all
It is preferable to have a water vapor transmission rate of.

The thus obtained medical adhesive sheet according to the present invention is used, for example, as a dressing material or a surgical tape, or as a first aid bandage having a liquid-absorbent pad in the central area of the surface of the adhesive layer. , Can also be used.

The medical pressure-sensitive adhesive sheet according to the present invention has excellent flexibility, and since the support layer is porous, it is unlikely to cause skin irritation due to swelling even after being applied for a long time. It is excellent.

[0030]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the examples. In the following, "part" means "part by weight" and "%" means "% by weight".

[Example 1] <Preparation of emulsion polymer particles A> The emulsion of the polymer particles having tackiness was 19.6 g of acrylic acid-2-ethylhexyl ester, 20 g of acrylic acid-2-methoxyethyl ester, and 0 acrylic acid. 0.4 g, potassium persulfate 1.44 g, sodium sulfite 0.88 g,
It was prepared by charging 0.14 g of cupric chloride and 760 g of water into a four-necked flask and stirring at 70 ° C. under a nitrogen atmosphere. At this time, no emulsifier was used (emulsifier-free emulsion polymerization). The average particle size of the obtained emulsion was 150 nm by the dynamic light scattering method (measured by DLS-700 manufactured by Otsuka Electronics Co., Ltd.).

<Preparation of Emulsion Polymer Particles B> An emulsion of tack-free polymer particles to be the support layer is 32 g of acrylic acid ethyl ester, 48 g of methacrylic acid methyl ester, 0.8 g of potassium persulfate and 72 parts of water.
Charge 0 g into a four-necked flask, and in a nitrogen atmosphere at 70 ° C.
It was prepared by stirring at. Preparation of the present polymer particles is also emulsion-free emulsion polymerization. Emulsion polymer particles A
The average particle size of the present polymer particles is 5 when measured in the same manner as
It was 42 nm.

<Preparation of Emulsion Blend Adhesive Sheet> The prepared emulsion polymer particles A and B were
The emulsion was blended at a mixing ratio of 1 (polymer particle solid content weight ratio), and aqueous ammonia was added to adjust the pH to 10. The total thickness of the support layer and the adhesive layer after film formation is 10
It was cast on a release paper so that the thickness became 0 μm. Then, it was dried in a constant temperature bath at 35 ° C. adjusted to a constant humidity (about 55%) to obtain an adhesive sheet. Hereinafter, the front surface side cast on the release paper is referred to as the air side, and the release paper surface side is referred to as the bottom side. In this example, the average particle size of the emulsion polymer particles A was made smaller than the average particle size of the emulsion polymer particles B, and the air side was designed to be the adhesive layer.

Example 2 The emulsion polymer particles A and B described above were emulsion-blended for the purpose of controlling the sedimentation rate, and then the blended polymer particles were treated with sodium sulfate (2.3 × 10 ⁻² M). Other than the addition and the fact that the humidity was not adjusted during drying,
An adhesive sheet was obtained by the same operation as in Example 1.

[Comparative Example] <Preparation of Emulsion Single Sheet> In the same manner as in the example, the emulsion polymer particles A and B were individually cast on release paper and dried to prepare Comparative Example 1 (emulsion polymer particle A). Sheet) and Comparative Example 2 (sheet of emulsion polymer particles B) were obtained. The coating amount was adjusted so that the thickness after film formation was 100 μm.

Table 1 shows the compounding ratio of the emulsion and the salt in Examples 1 and 2 and Comparative Examples 1 and 2.

[0037]

[Table 1]

[Evaluation method] <Adhesive strength> About the obtained sheet, a double-sided tape was attached to the air side or the bottom side, and 25 sheets was attached on the double-sided tape.
After sticking a PET film of μm, it was cut into a width of 20 mm and a length of 150 mm and stuck to a phenol resin plate.
The roller was reciprocated once with a roller having a weight of 2 kg and pressure-bonded. After 30 minutes, using a tensile tester, the adhesion was measured at room temperature at a pulling speed of 300 mm / min and 180 ° peeling.

<Microscopic Observation> Both surfaces and cross sections of the produced pressure-sensitive adhesive sheet were observed with a scanning electron microscope (manufactured by Hitachi Ltd.,
S-2500).

<Measurement of Moisture Permeability> A predetermined amount of distilled water was placed in a moisture permeable cup, the upper part was covered with a test piece, and the weight was measured. Then, it was stored under constant temperature and humidity at 40 ° C. and a humidity of 30%, and the weight was measured every predetermined time. The water vapor transmission rate was calculated from the reduced weight (unit: g · 24 h / m ² ).

Table 2 shows the measurement results of the adhesive strength and the water vapor transmission rate.

[0042]

[Table 2]

The adhesive force on the air side of the sheet of the example was 10 N / 20 mm or more, and it was confirmed that sufficient adhesive force was exhibited. In addition, since the bottom side of the sheet according to Example 1 does not exhibit adhesive force,
By the method according to the present invention, the pressure-sensitive adhesive layer (air side)
It is clear that the tack-free support layer (bottom side) is formed separately.

Regarding the water vapor transmission rate, both Examples 1 and 2 have values equal to or higher than those of the comparative example. This means that a porous sheet was obtained by the method according to the present invention.

In Comparative Example 1, the same moisture permeability as that of the Example is shown, but since Comparative Example 1 is composed of only the pressure-sensitive adhesive layer, when it is actually used as a medical pressure-sensitive adhesive sheet, a separate support is used. Need to be laminated. In this case, even if a film of polyurethane (relatively high moisture permeability) or the like is laminated as the support layer, the moisture permeability may decrease. This can be easily inferred from the fact that when the non-porous support layer as in Comparative Example 2 is used, it exhibits an extremely low moisture permeability.

An electron micrograph of the sheet of Example 1 is shown in FIG.
Shown in. 2 (a) is a photograph of the entire sheet, and FIG. 2 (b).
2C is an enlarged photograph of the air side, FIG. 2C is an enlarged photograph of the bottom side, and FIG. 2D is an enlarged photograph of the vicinity of the boundary between the air side and the bottom side. From these photos,
It was confirmed that the tack-free support film and the adhesive film were separated, and that both layers were porous films.

[0047]

In the production of the pressure-sensitive adhesive sheet according to the present invention, it is not necessary to use an organic solvent, a plasticizer, an emulsifier and a material containing chlorine such as vinyl chloride, so that the load on the environment should be minimized. You can Further, since the medical adhesive sheet according to the present invention has the porous adhesive layer and the support layer, it is not significantly affected by the moisture permeability of the material itself, and exhibits high moisture permeability as the whole medical adhesive sheet. for that reason,
Since the range of choices of materials to be used is widened, it is possible to provide a medical pressure-sensitive adhesive sheet that uses less expensive materials such as acrylic resin and has less unevenness even when used for a long time.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for producing a pressure-sensitive adhesive sheet according to the present invention.

2 is an electron micrograph of the sheet of Example 1. FIG. In addition, (a) is a photograph of the entire seat, (b) is an enlarged photograph of the air side, (c) is an enlarged photograph of the bottom side,
(D) is an enlarged photograph near the boundary between the air side and the bottom side.

[Explanation of symbols] 1: Release paper 2: Water 3: Tack-free polymer particles 4: Adhesive polymer particles

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 201/00 A61L 15/01 (72) Inventor Masayoshi Okubo 1-1 Rokkodai-cho, Nada-ku, Kobe-shi, Hyogo Kobe University Faculty of Engineering F-term (Reference) 4C076 AA74 BB31 DD22 DD23 DD24 DD26 EE09 4C081 AA03 AA12 BB02 BC01 BC04 CA08 CF25 DA02 EA02 4J004 AA10 AB01 CA03 CC07 FA09 GA01 4J040 DB062 DE022 DF012 DF02 MA150902 DF021 DF021 DF082 DF021 DF021DF082

Claims (12)

[Claims] 1. An emulsion containing polymer particles having tackiness and polymer particles having no tackiness is applied, and a layer having tackiness (adhesive layer) is provided on one side in the thickness direction of the sheet to face each other. A method for producing a pressure-sensitive adhesive sheet, which comprises forming a layer (support layer) having no tackiness on one side. 2. A polymer layer in which one of the two types of polymer particles has a higher sedimentation speed in the emulsion than the other, and a pressure-sensitive adhesive layer is provided on one side in the thickness direction of the sheet, and a support layer is provided on the opposite side. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive sheet is formed. 3. The settling rate of the polymer particles having a higher sedimentation rate in the emulsion is at least twice the sedimentation rate of the polymer particles having a lower settling rate.
The method for producing the pressure-sensitive adhesive sheet according to. 4. One of the two types of polymer particles has a larger sedimentation rate in the emulsion than the other, and one of the two types of polymer particles has a larger average particle size in the emulsion than the other. The method for producing a pressure-sensitive adhesive sheet according to claim 2, wherein polymer particles are used. 5. The average particle size of polymer particles having a larger average particle size in the emulsion is 2 to 100 times that of polymer particles having a smaller average particle size.
The method for producing the pressure-sensitive adhesive sheet according to. 6. The method for producing a pressure-sensitive adhesive sheet according to claim 4, wherein the difference between the average particle diameters of the two types of polymer particles in the emulsion is 100 to 5000 nm. 7. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the two types of polymer particles are acrylic polymer particles. 8. The emulsion according to claim 1, which is an aqueous emulsion containing no emulsifier.
7. The method for producing the pressure-sensitive adhesive sheet according to any one of 7. 9. The emulsion comprises sodium sulfate,
The method for producing a pressure-sensitive adhesive sheet according to claim 1, further comprising at least one salt selected from the group consisting of sodium chloride, sodium nitrate and sodium phosphate. 10. A medical pressure-sensitive adhesive sheet produced by the method according to claim 1. 11. The porosity of the support layer is 5% or more,
The medical adhesive sheet according to claim 10. 12. The water vapor transmission rate is 1000 g · 24 h / m ²
The medical pressure-sensitive adhesive sheet according to claim 10, which is as described above.