JP2008132011A - Swab comprising hydrophilic continuous porous member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a swab (1) having no self-dusting properties and equal to a conventional swab in water absorption amount and water absorption speed, that is, a swab causing no falling-off and having a good liquid absorbing capacity, a swab (2) flexible in the contact part provided to the leading end of its shaft part, giving no damage to a living body part and not damaged by load when used and a swab (3) prevented from the falling-off of the contact part from its shaft part, eluting no harmful substance and capable of being also subjected to sterilization/incineration operation. <P>SOLUTION: The swab is composed of the shaft part and the contact part provided to the leading end of the shaft part and the contact part comprises a hydrophilic continuous porous member formed of an olefinic thermoplastic resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cotton swab comprising a hydrophilic continuous porous material used in medical sites such as otolaryngology, cosmetic applicators, industrial (especially precision instruments) cleaning tools, and the like. The present invention relates to a cotton swab made of a hydrophilic continuous porous body formed from an olefin-based thermoplastic resin.

In general, a cotton swab uses a material such as paper, plastic, or wood for the shaft portion, and the cotton body portion has one end of the shaft or both ends wrapped with cotton. Cotton bodies have various shapes by compression molding depending on the application. A special cotton swab that prevents fraying of the cotton in the cotton body portion is also considered. For example, a multilayer fiber cotton swab in which a content fiber part made of cotton fiber or the like provided at the tip of a shaft body is covered with an outer fiber part made of a chemical fiber having heat melting property, heat shrinkability or heat fixability ( Patent Document 1) and cotton swabs in which a cotton body is covered with gauze or nonwoven fabric have been developed.
However, because cotton is used, there is always the possibility that fiber scraps may adhere, there may be residual chemicals when the cotton is exposed, and moreover, the cotton thread is wound around the shaft. Since an adhesive is used, there have been reports of drawbacks such as the possibility of the adhesive being eluted.

At medical sites such as otolaryngology, doctors and nurses wrap cotton around the tip of a thin stainless steel shaft (cotton floss) every time it is used. Remove and re-use shaft after disinfection. On the other hand, cotton swabs marketed for household use have a cotton ball formed at the end of the shaft by factory production, but glue is used when forming the cotton ball part at the manufacturing stage.
However, the conventional medical swab is a method in which cotton is manually wound or removed at a medical site, which is troublesome and unsanitary. In addition, if the cotton is wound for a long time, the cotton will return naturally and the winding will become loose. In addition, because the shaft is reused for many patients, there is a risk of nosocomial infections. On the other hand, a commercially available cotton swab for general households is unacceptable for medical use because paste is used in the cotton ball part.

Cotton swabs used for cosmetic applicators, industrial (especially for precision instruments) cleaning tools, etc. are generally made by winding cotton fibers around a thin shaft in a spherical or spindle shape. Since this cotton fiber is simply wound around each other, the polyvinyl alcohol is placed on the outer surface of the wound cotton lump in order to prevent fraying of fibers and detachment of fiber waste such as short fibers. It is also practiced to apply a thin paste such as a paste. However, since the sizing agent merely merely hardens the entangled portion between the fibers, there is a problem that the fiber waste is easily detached. When used for cleaning precision instruments, it is necessary to prevent such fiber scraps from falling off.
Patent Document 2 describes a cotton swab in which a resin having good releasability such as silicone rubber is attached to the outer surface of a cotton lump. By covering the surface of the cotton lump part with the resin in this way, the fiber waste can be prevented from falling off. However, there is a problem that the liquid absorption performance of the cotton lump, which is the original characteristic of the swab, is impaired by coating with resin. For example, when a cotton lump is impregnated with an organic solvent and a precision instrument is cleaned, the amount of impregnation of the organic solvent is low, which may hinder the cleaning operation for removing dirt with the solvent, and may not be sufficiently cleaned. . Also, when applying cosmetics, if the amount of cosmetic impregnation and discharge is low, the application of cosmetics will be hindered.

Japanese Patent Publication No. 55-44979 JP 09-47377 A

In view of the above-mentioned problems of the prior art, the present invention provides (1) a cotton swab having no self-dusting and having the same amount of water absorption and speed as that of a conventional cotton swab. An object of the present invention is to provide a cotton swab having good liquid absorption performance. In addition, (2) To provide a cotton swab that has a flexible contact portion provided at the tip of the shaft portion, does not damage the living body part, and does not break even with a load during use. 3) contact portion be those that do not fall off from the shaft portion, and an object thereof is to provide a possible swab sterilization / incineration operations.

  As a result of intensive studies, the present inventors have found that a cotton swab characterized by comprising a hydrophilic continuous porous body formed from an olefin-based thermoplastic resin has no self-dusting, and has a conventional water absorption amount and water absorption rate. The present inventors have found that it is equivalent to a cotton swab and completed the present invention.

That is, the invention according to claim 1 is a cotton swab comprising a shaft portion and a contact portion provided at the tip of the shaft portion, wherein the contact portion is formed of a hydrophilic continuous material formed from an olefin-based thermoplastic resin. The present invention relates to a cotton swab characterized by comprising a porous body.
The invention according to claim 2 is characterized in that the hydrophilic continuous porous body is molded by kneading at least a pore forming agent into an olefinic thermoplastic resin, and at least a part of the obtained molded product is obtained from the melting point of the resin. It is obtained by immersing in a liquid at a high temperature, then eluting the pore with a water-based solvent to obtain a continuous porous body, and then impregnating the continuous porous body with a solution containing a surfactant and drying it. The cotton swab according to claim 1, wherein the cotton swab is provided.
The invention according to claim 3 is characterized in that the hydrophilic continuous porous body is molded by kneading at least a pore forming agent and a pore forming aid into an olefin-based thermoplastic resin, and then at least a part of the obtained molded product. After immersing in a liquid having a temperature higher than the melting point of the resin and then elution of the pore with an aqueous solvent to obtain a continuous porous body, the continuous porous body is impregnated with a solution containing a surfactant and dried. The swab according to claim 1, wherein the swab is obtained by making the
The invention according to claim 4 is characterized in that the hydrophilic continuous porous body is formed by kneading and molding at least a pore forming agent, a pore auxiliary agent and a surfactant into an olefinic thermoplastic resin. After immersing at least a part in a liquid having a temperature higher than the melting point of the resin and then eluting the pore with an aqueous solvent to obtain a continuous porous body, a solution containing a surfactant in the continuous porous body is obtained. 2. The swab according to claim 1, wherein the swab is obtained by impregnation and drying.
The invention according to claim 5 is characterized in that the hydrophilic continuous porous body is higher than the melting point of the resin after being molded by kneading at least a pore forming agent, a pore assisting agent and a surfactant into an olefinic thermoplastic resin. 2. The swab according to claim 1, wherein the swab is obtained by dipping in a liquid at a temperature and then eluting the pore with an aqueous solvent.
The invention according to claim 6 is characterized in that the olefinic thermoplastic resin is at least one selected from the group consisting of ethylene vinyl acetate copolymer, polyethylene, and polypropylene. Related to cotton swabs.
The invention according to claim 7 relates to the swab according to any one of claims 2 to 5, wherein the pore forming agent is a water-soluble organic substance not containing metal ions.
The invention according to claim 8 relates to the swab according to any one of claims 3 to 5, characterized in that the pore-forming aid is a monomer or polymer of a polyhydric alcohol.
The invention which concerns on Claim 9 is related with the cotton swab in any one of Claims 1 thru | or 8 provided for medical use.
The invention according to claim 10 relates to a cotton swab according to any one of claims 1 to 8 used for cosmetic purposes.

The cotton swab according to the present invention has good fluidity, has a smooth surface and does not form dust, and thus does not self-dust (drop off fiber waste). In addition, the water absorption amount and the water absorption speed are equivalent to those of conventional cotton swabs (having good liquid absorption performance). In addition, the contact portion (head) does not fall off the shaft portion, and it is not damaged due to a load during use.
Further, the cotton swab according to the present invention has a flexible contact portion provided at the tip of the shaft portion, so that it does not damage the living body part and also deteriorates physical properties against sterilization treatment such as γ-ray irradiation. It is hygienic and safe. In addition, since no harmful substances are eluted even after incineration after use, there is no environmental impact at the time of disposal.

As a result of diligent research, the present inventors have found that a cotton swab made of a hydrophilic continuous porous body formed from an olefin-based thermoplastic resin has no self-dusting, and has the same amount of water absorption and water absorption as a conventional swab. As a result, the present invention has been completed.
Hereinafter, embodiments of the present invention will be described.

  The “cotton swab comprising a hydrophilic continuous porous body” according to the present invention comprises a shaft portion and a contact portion (head) (hereinafter referred to as “contact portion”) provided at the tip of the shaft portion. The “contact portion” will be described.

[Material of contact part]
The material of the “contact portion” of the swab according to the present invention is not particularly limited as long as it is a hydrophilic continuous porous body formed from an olefin-based thermoplastic resin. The porous continuous porous body produced by the porous body and the production method thereof is desirable.
Hereinafter, the hydrophilic continuous porous material as a raw material in the “contact portion” of the “swab made of the hydrophilic continuous porous material” according to the present invention and a method for producing the same will be described in detail.

[Hydrophilic continuous porous body and method for producing the same]
A hydrophilic continuous porous body is manufactured from the following processes.
(1) Kneading and molding at least a pore forming agent in an olefinic thermoplastic resin (2) Soaking at least a part of the molded product in a liquid having a temperature higher than the melting point of the resin (3) In step 2 The shaped pores in the resulting molded article are eluted with an aqueous solvent to obtain a continuous porous body (4) The continuous porous body is impregnated with a solution containing a surfactant and dried.

In the step (1), at least a pore forming agent is kneaded and molded into the olefinic thermoplastic resin. The olefin-based thermoplastic resin (hereinafter sometimes simply referred to as a thermoplastic resin) is not particularly limited, and polyethylene, polypropylene, polybutene (polybutylene), ethylene vinyl acetate copolymer, ethylene propylene copolymer, ethylene butene copolymer. And propylene butene copolymer. In particular, in the present invention, it is preferable to use an ethylene vinyl acetate copolymer as the olefin-based thermoplastic resin. Since the ethylene vinyl acetate copolymer has a relatively low melting point, it can be easily kneaded and molded.
When an ethylene vinyl acetate copolymer is used as the olefin-based thermoplastic resin, the hardness, rebound resilience, strength, etc. of the hydrophilic continuous porous body can be adjusted by the vinyl acetate content. In the present invention, the content of vinyl acetate is not particularly limited, but is preferably adjusted to about 5 to 40% by weight in the total amount of ethylene vinyl acetate copolymer. Olefin-based thermoplastic resins, especially ethylene vinyl acetate copolymers, unlike polyurethane and NBR, have excellent solvent resistance and do not generate malodors or dioxins even when incinerated.

  The pore-forming agent kneaded with the olefinic thermoplastic resin is a particulate substance that does not dissolve in the olefinic thermoplastic resin but dissolves in the aqueous solvent. Preferably, a water-soluble organic substance is used. By eluting the pore former kneaded into the olefinic thermoplastic resin, open cells can be formed.

  Examples of the water-soluble organic material include starch such as corn starch, wheat starch and potato starch, polysaccharides such as sugar and hemicellulose, tetramethylolmethane, pentaglycerin, hexitol, glycitol, and peptitol. More preferably, tetramethylolmethane is used. In the present invention, one or two or more types of pore forming agents described above can be used.

  The blending amount of the pore forming agent is not particularly limited, and is arbitrarily arbitrarily blended depending on the porosity of the continuous porous body to be produced. For example, when a continuous porous body having a porosity of 40 to 80% is manufactured, the amount of the pore former is 250 to 450 parts by weight with respect to 100 parts by weight of the thermoplastic resin. The particle diameter of the pore forming agent is not particularly limited, and is adjusted according to the pore diameter of the continuous porous body to be produced.

In the step (1), a hole forming aid may be kneaded together with the hole forming agent.
A pore-forming aid is used to shorten the water elution time of the pore-forming agent, and those having a high boiling point, which can improve the fluidity of the resin with a small amount, and those having a small loss on heating are preferably used.
In the present invention, a monomer or polymer of a polyhydric alcohol is used. Specifically, monomers of polyhydric alcohols such as ethylene glycol, glycerin, propylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether; diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, polyethylene glycol Examples thereof include polymers of polyhydric alcohols such as
The pore-forming aid not only shortens the water elution time of the pore-forming agent but also has an effect of improving the plasticity of the resin. In the present invention, it is preferable to use a polymer of polyhydric alcohol as the pore-forming aid. By using a polymer of a polyhydric alcohol as a pore-forming aid, a hydrophilic continuous porous body whose hydrophilicity lasts for a long period of time can be produced.

Although the compounding quantity of the shape aid added in the step (1) is not particularly limited, it is 10 to 100 parts by weight, preferably 20 to 80 parts by weight, more preferably 30 to 70 parts by weight with respect to 100 parts by weight of the thermoplastic resin. It is preferable to mix. If the amount is less than 10 parts by weight, the effect of blending the pore former cannot be obtained, and even if the amount exceeds 100 parts by weight, no significant increase in the effect is observed.
As described above, the compounding amount of the shape hole assistant may be relatively small. In step (2), at least a part of the molded product obtained in step (1) is immersed in a liquid having a temperature higher than the melting point of the thermoplastic resin, so that the molded product expands and This is because the elution time of the pore forming agent can be shortened by increasing the surface area and the space ratio. That is, since the molded product in the step (2) is in an uncompressed and non-pressurized state, the elution time can be shortened by the expansion of the molded product. Therefore, it is added in the step (1) for the purpose of shortening the elution time. The amount of the shape aid may be relatively small.

  The temperature at the time of kneading in the step (1) is not particularly limited, and may be appropriately set according to the thermoplastic resin to be used, but is usually 130 to 180 ° C.

  In step (1), a surfactant can be kneaded in addition to the pore-forming agent and the pore-forming aid. By kneading the surfactant, it is possible to impart stronger hydrophilicity to the porous body. The surfactant to be kneaded in addition to the pore forming agent and the shape pore auxiliary agent is not particularly limited, and is a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant. Can be used. In particular, in the present invention, it is preferable to use a surfactant such as a nonionic surfactant, a cationic surfactant, an anionic surfactant or an amphoteric surfactant as described later. More preferably, an activator or an anionic surfactant is used. When the surfactant is kneaded, the blending amount is not particularly limited, but is 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic resin. Partly formulated. If it is less than 0.1 part by weight, the effect of imparting hydrophilicity to the porous body is poor. Even if the amount exceeds 10 parts by weight, no significant increase in the effect is observed.

  The above materials are kneaded into a thermoplastic resin and then molded into a required shape. The molding method is not particularly limited, and molding is performed by compression molding, extrusion molding, injection molding, calendar molding, or the like. In particular, when the cotton swab of the present invention is produced, it is desirable to use an injection molding method. When molding by the compression molding method, it is compressed to a predetermined thickness at 60 to 160 ° C. When forming into a sheet form or a roll form, it shape | molds by the extrusion method.

  Next, in step (2), at least a part of the obtained molded product is immersed in a liquid having a temperature higher than the melting point of the thermoplastic resin.

  The liquid used in step (2) is preferably a polyhydric alcohol monomer or polymer. Specifically, monomers of polyhydric alcohols such as ethylene glycol, glycerin, propylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether; diethylene glycol, triethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, polyethylene glycol Examples thereof include polymers of polyhydric alcohols such as

  The temperature of the liquid used in the step (2) is set to a temperature higher than the melting point of the thermoplastic resin. Preferably, the temperature is 10 to 70 ° C higher than the melting point, more desirably 30 ° C to 50 ° C higher than the melting point.

In the step (2), either a method of immersing the molded product in the liquid having the above temperature or a method of heating the molded product to the temperature after immersing the molded product in the liquid may be employed.
In any case, by performing this step (2), the three-dimensional resin skeleton structure of the hydrophilic continuous porous body becomes a branch tree shape without a film, and not only on the surface but also on the entire interior. Improved. Further, since the degree of communication can be controlled by adjusting the temperature and immersion time of the liquid, the temperature and immersion time of the liquid are preferably adjusted according to the use of the hydrophilic continuous porous body. For example, in the case of improving only the skin layer on the surface, a method may be employed in which the liquid having the temperature is applied only to the surface, or the liquid is applied to the surface and then heated to obtain the temperature.

  In step (3), the pore former in the molded product obtained in step (2) is eluted with an aqueous solvent to obtain a continuous porous body. Examples of the aqueous solvent include water, water-soluble lower aliphatic alcohol, dilute acid water, dilute alkaline water and the like, and usually water or warm water is preferably used. When an acid or alkali is used as the aqueous solvent, it is used at a low concentration so as not to cause pollution.

  Next, in step (4), the continuous porous material obtained in step (3) is impregnated with a solution containing a surfactant and dried. That is, by impregnating the porous body with the solution containing the surfactant, the surfactant can be attached to the surface of the porous body and the surface of the pores. Thereby, hydrophilicity can be imparted to the porous body that is lipophilic. In the case of a porous body formed by previously kneading a surfactant in a resin, hydrophilicity is imparted even if this step (4) is omitted, but in order to impart stronger hydrophilicity. Also in the case of a porous body formed by previously kneading a surfactant in a resin, it is preferably impregnated with a solution containing the surfactant.

Examples of the surfactant include nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants.
Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene derivatives, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxy Examples thereof include ethylene fatty acid esters, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamines, alkyl alkanolamides, and sucrose fatty acid esters.

  Examples of the cationic surfactant include distearyldimethylammonium chloride, stearyltrimethylammonium chloride, stearyldimethylbenzylammonium chloride, and benzalkonium chloride.

  Anionic surfactants include soaps, alkyl sulfates, polyoxyethylene alkyl ether sulfates, alkyl naphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, fatty acid salts, higher alcohol sulfates. And alkyl allyl sulfonate.

  Examples of amphoteric surfactants include lauryl dimethylaminobutyric acid betaine, alkyldiaminoethylglycine chloride solution, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium and the like.

  In particular, in the present invention, it is preferable to use a nonionic surfactant or an anionic surfactant, and it is more desirable to use an anionic surfactant.

The surfactant is dissolved in a liquid capable of dissolving the surfactant, preferably water.
The concentration of the surfactant in the solution containing the surfactant is not particularly limited, but is 0.01 to 5% by weight, preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight. . When the content is less than 0.01% by weight, it becomes difficult to impart hydrophilicity to the continuous porous body. If it exceeds 5% by weight, no further effect can be obtained.

  The hydrophilic continuous porous body according to the present invention can be obtained by impregnating the porous body with a solution containing a surfactant and then drying. The method for drying the porous body impregnated with the solution containing the surfactant is not particularly limited, and examples thereof include hot air drying and sun drying. By drying under the temperature and humidity conditions, a hydrophilic porous material that can form a strong bond between the surfactant and the thermoplastic resin constituting the porous body and can maintain the hydrophilicity for a long period of time. You can get a body.

  In the present invention, the step of impregnating the porous body with the solution containing the surfactant and drying may be performed at least once, and may be performed a plurality of times as necessary. By performing a plurality of times, hydrophilicity can be imparted more firmly.

  In the production method of the present invention, additives such as pigments, antioxidants, conductivity-imparting agents, and UV degradation inhibitors can be appropriately blended as necessary. Among these, as a pigment, the pigment used with a normal continuous porous body may be used, Specifically, carbon black, charcoal, white titanium etc. can be illustrated. Other examples include additives that are easily eluted from thermoplastic resins such as plasticizers and silicone oils. For example, when these additives are used as a wiping material, dirt may adhere to the object, so it is desirable not to use them depending on the intended use of the hydrophilic continuous porous body. That is, it is preferable to determine whether or not to use an additive that is easily eluted from a thermoplastic resin such as a plasticizer or silicone oil in consideration of the intended use of the hydrophilic continuous porous body.

The hydrophilic continuous porous body according to the present invention has a branch tree shape and a water retention rate of 100 to 555%, preferably 100 to 700%. Further, when the water absorption speed is measured from the rising time of water when the lower end of the test piece 10 mm is immersed in water, the time required for the water to rise 10 mm from the water surface is 4 seconds or less, preferably 3 seconds or less. It takes 7 seconds or less, preferably 6 seconds or less, to take 20 mm from the water surface and has very high hydrophilicity. Moreover, the hydrophilic continuous porous body according to the present invention has hydrophilicity for a long period of time.
The “branch tree” refers to a state in which the thermoplastic resin is irregularly connected like a branch tree in a rod shape. Specifically, it refers to a shape in which a film-like collar portion is fused into a rod shape to form a three-dimensional skeleton structure.

(Shape of contact part)
The shape of the “contact portion” of the cotton swab comprising the hydrophilic continuous porous body according to the present invention is not particularly limited as long as it is a shape that does not damage the living body and can be molded by injection molding. Although it is not a thing, it is desirable that the shape has no sharp protrusion because it does not damage the living body.

  Next, the “shaft” of the cotton swab made of the hydrophilic continuous porous material according to the present invention will be described.

[Shaft material]
As long as the material of the shaft of the “cotton swab comprising a hydrophilic continuous porous body” according to the present invention is a resin that is flexible with respect to bending, has good compatibility with the contact portion (head), and has good moldability. Although not particularly limited, those satisfying the following requirements 1) to 7) are desirable.
1) Even if it bends, it is hard to break.
2) Does not contain harmful substances.
3) Good compatibility with the material of the contact part.
4) Sterilization and incineration are possible.
5) No change over time (about 1 year).
6) There is no self-dusting (dropping of fiber waste).
7) The contact part does not fall off the shaft part.

[Shaft shape]
The shape of the “shaft portion” of the cotton swab according to the present invention is a shape that does not damage the living body, and is a shape in which the shaft portion does not come off from the contact portion (head), and the contact portion. As long as the shape is such that the shaft is not decentered in the contact portion due to the injection pressure, there is no particular limitation.

  Next, a method for manufacturing and forming a cotton swab according to the present invention will be described.

〔Manufacturing process〕
1) Molding The shaft part is molded, and then the shaft part is inserted to form the contact part (head).
2) Cleaning The molded product is cleaned with pure water to remove the pore-generating agent.
3) Drying For example, dry at 50 ° C. for 1.5 hours to remove moisture.
4) Inspection Inspection 1 Total Image determination
Appearance inspection (foreign matter, black spots, dirt, deformation)
Inspection 2 sampling (each lot)
・ Water absorption rate ・ Moisture content ・ Water absorption rate ・ Residue ・ Color ・ Tensile strength ・ Eccentricity ・ Shaft appearance ・ Shaft bending strength 5) Packaging

[Molding method]
Injection molding-Molding procedure 1) Mold the shaft.
2) Insert the shaft part into another mold, and then mold the contact part (head).

The cotton swab according to the present invention obtained as described above can be sterilized.
Specific methods of sterilization include, for example, ethylene oxide gas sterilization, γ-ray sterilization, and electron beam sterilization.

Hereinafter, the “hydrophilic continuous porous body” which is a material of the contact portion in the cotton swab of the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following examples.
(Example 1)
The following materials were put into a barrel, heated to 135 ° C. and kneaded for about 20 minutes.
Material used Amount used (parts by weight)
EVA resin 100
Tetramethylolmethane 320
Pigment 1
After kneading, it was compression molded to a thickness of 1 mm by a compression molding method.
The obtained molding was immersed in polyethylene glycol at 110 ° C. for 40 minutes. Thereafter, the mixture was stirred for 1 hour in warm water to elute tetramethylolmethane to obtain a continuous porous body. The EVA resin used has a melting point of 78 ° C. Next, the continuous porous body was immersed in a 1% by weight aqueous solution of a surfactant (alkyl sulfate ester salt) for 2 hours and then dried at 50 ° C. for 1.5 hours to obtain a hydrophilic continuous porous body. .

(Example 2)
The following materials were put into a barrel, heated to 135 ° C. and kneaded for about 20 minutes.
Material used Amount used (parts by weight)
EVA resin 100
Polyethylene glycol 30
Tetramethylolmethane 160
Starch 160
Pigment 1
After kneading, it was formed into a 1 mm thick sheet by an extrusion method.
The obtained molded article was immersed in polyethylene glycol at 110 ° C. for 10 minutes. Thereafter, the mixture was stirred in water for 20 minutes to elute tetramethylolmethane and starch to obtain a continuous porous body. The EVA resin used has a melting point of 78 ° C.
Next, the continuous porous body was immersed in a 1% by weight aqueous solution of a surfactant (higher alcohol sulfate ester salt) for 2 hours and then dried at 50 ° C. for 1 hour to obtain a hydrophilic continuous porous body.

(Example 3)
The following materials were put into a barrel, heated to 135 ° C. and kneaded for about 20 minutes.
Material used Amount used (parts by weight)
EVA resin 100
Polyethylene glycol 30
Tetramethylolmethane 320
Sorbitan fatty acid ester 1
Pigment 1
After kneading, it was formed into a 1 mm thick sheet by an extrusion method.
The obtained molded article was immersed in polyethylene glycol at 110 ° C. for 3 minutes. Thereafter, the mixture was stirred in water for 20 minutes to elute tetramethylolmethane to obtain a continuous porous body. The EVA resin used has a melting point of 78 ° C. Next, the continuous porous body was immersed in a 1% by weight aqueous solution of a surfactant (polyoxyethylene alkyl ether) for 2 hours and then dried at 50 ° C. for 1 hour to obtain a hydrophilic continuous porous body.

Example 4
The following materials were put into a barrel, heated to 180 ° C. and kneaded for about 20 minutes.
Material used Amount used (parts by weight)
Polyethylene resin 100
Polyethylene glycol 30
Sorbitan fatty acid ester 1
Starch 320
Pigment 1
After kneading, it was formed into a 1 mm thick sheet by an extrusion method. The obtained molded product was immersed in polyethylene glycol at 180 ° C. for 3 minutes. Thereafter, the mixture was stirred in water for 20 minutes to elute the starch to obtain a continuous porous body. The melting point of the polyethylene resin used is 135 ° C.
Next, the continuous porous body was immersed in a 1% by weight aqueous solution of a surfactant (polyoxyethylene fatty acid ester) for 2 hours and then dried at 50 ° C. for 1 hour to obtain a hydrophilic continuous porous body.

(Comparative Example 1)
The following materials were put into a barrel, heated to 135 ° C. and kneaded for about 20 minutes.
Material used Amount used (parts by weight)
EVA resin 100
Tetramethylolmethane 320
Pigment 1
After kneading, it was compression molded to a thickness of 1 mm by a compression molding method. Thereafter, the mixture was stirred for 3 hours in warm water to elute tetramethylolmethane to obtain a continuous porous body. The EVA resin used has a melting point of 78 ° C.
Next, the continuous porous body was immersed in a 1% by weight aqueous solution of a surfactant (alkyl sulfate ester salt) for 2 hours and then dried at 50 ° C. for 4 hours to obtain a hydrophilic continuous porous body.

(Comparative Example 2)
The following materials were put into a barrel, heated to 135 ° C. and kneaded for about 20 minutes.
Material used Amount used (parts by weight)
EVA resin 100
Polyethylene glycol 30
Tetramethylolmethane 320
Pigment 1
After kneading, it was compression molded to a thickness of 1 mm by a compression molding method. Thereafter, the reaction mixture was stirred in warm water for 2 hours to elute tetramethylolmethane to obtain a continuous porous body. The EVA resin used has a melting point of 78 ° C.
Next, the continuous porous body was immersed in a 1% by weight aqueous solution of a surfactant (alkyl sulfate ester salt) for 2 hours and then dried at 50 ° C. for 2 hours to obtain a hydrophilic continuous porous body.

(Test Example 1; photomicrograph)
FIG. 1 shows the hydrophilic continuous porous body of the present invention obtained in Example 3, and FIG. 2 shows the conventional hydrophilic continuous porous body obtained in Comparative Example 2.
As shown in FIGS. 1 and 2, the hydrophilic continuous porous body of the present invention has a three-dimensional structure in which the internal structure is a branch tree shape, and the film-like collar portion is melted into a rod shape as compared with the conventional porous body. Has a skeletal structure.

(Test Example 2: Measurement of physical properties)
The physical property values of the continuous porous bodies of Examples 1-4 and Comparative Examples 1-2 prepared above were measured. The results are listed in Table 1.
In addition, the calculation method of a water retention rate is as follows. The mass (M1) of the continuous porous body of Examples and Comparative Examples cut to a size of 25 cm × 25 cm was measured, and then the mass (M2) of the continuous porous body immersed in distilled water for 10 minutes was measured. It was measured. And water retention (%) was computed by {(M2-M1) / M1} * 100.
The water absorption rate was measured according to the following method. First, each of the above samples was cut into strip-shaped test pieces having a length of 100 mm, a width of 20 mm, and a thickness of 1.6 mm. Next, this test piece was put into a ventilation dryer at 35 ° C. and dried for 2 hours. The upper end of this test piece was held, the lower end 10 mm was immersed in water at 25 ° C., and the rising time of water was measured. The time required for the water to rise 10 mm and 20 mm from the water surface was shown in Table 1.

As shown in the results of Table 1, it can be seen that the hydrophilic continuous porous body according to the present invention has good hydrophilicity.
In addition, each sample of Examples 1 to 4 was used for 3 hours a day for 1 week as a water absorption roll having a 30 mm outer diameter, a length of 200 mm, and a thickness of 5 mm as a water absorption after washing the computer base. Then, when the water retention rate and the water absorption rate were measured, the water retention rate and the water absorption rate were approximately the same as described above.

(Test Example 3; mechanical strength against friction)
Using Example 3 and Comparative Example 2, the mechanical strength of the hydrophilic continuous porous material of the present invention was measured.
After applying the lipstick to the spectacle lens, it was wiped off in a dry state by the same shape and volume continuous porous body of Example 3 and Comparative Example 2. As a result, in Example 3, generation of small pieces due to friction was not observed, the spectacle lens returned to a clean state, and an excellent wiping effect for dirt was confirmed. On the other hand, in Comparative Example 2, a large number of small pieces of continuous porous material were generated due to friction generated during wiping, and the spectacle lens surface was contaminated.
(Test Example 4; wiping effect)
Using Example 3, the wiping effect of the hydrophilic continuous porous material of the present invention was confirmed.
When the oily stain on the liquid crystal screen of the mobile phone was wiped off by the continuous porous body of Example 3, the liquid crystal screen of the mobile phone was in a clean state and exhibited an excellent wiping effect against dirt such as an oil film. I was able to confirm.
After immersing pure water in the continuous porous body of Example 3, dirt such as dust on the glass surface and the liquid crystal screen was wiped off. As a result, since the frictional resistance was smaller than that in the dry state, the wiping effect was increased.
After immersing methyl ethyl ketone in the continuous porous body of Example 3, and using this to wipe off the dirt of the plastic molding die, the dirt was completely wiped off without volume expansion and tissue destruction of the continuous porous body.

(Test Example 5: Comparison of elution time of pore shape agent)
The comparative example 1 is manufactured by the same raw material and manufacturing method as Example 1 except not performing the process 2. FIG. When the elution times of these pores were compared, it was 1 hour in Example 1 and 3 hours in Comparative Example 1. When the residue of the obtained pore forming agent (tetramethylolmethane) of Example 1 and Comparative Example 1 was measured, Example 1 was 8 mg / cm ³ and Comparative Example 1 was 9 mg / cm ^3. It was about.
From the above results, it can be seen that the elution time for elution of the same amount of the pore forming agent was remarkably shortened in Example 1.

(Test Example 6: Comparison of drying time of hydrophilic continuous porous body)
The comparative example 1 is manufactured by the same raw material and manufacturing method as Example 1 except not performing the process 2. FIG. When the drying time of these continuous porous bodies was compared, it was 1.5 hours in Example 1 and 4 hours in Comparative Example 1. When the moisture remaining amount of the obtained Example 1 and Comparative Example 1 was measured, Example 1 was 3 mg / cm ³ and Comparative Example 1 was 3 mg / cm ³ , both of which were comparable.
From the above results, it can be seen that the drying time of the continuous porous body was significantly shortened in Example 1.

(Test Example 7; solvent resistance)
Evaluation of the solvent resistance of each sample of Examples 1 to 4 against n-hexane, cyclohexane, n-butyl nitrate, methyl isobutyl ketone, ethyl acetate, methyl ethyl ketone, cellosolve, acetone, dioxane, isopropanol, dimethylformamide, ethanol, methanol As a result, it was confirmed that the film was immersed in all the above-mentioned solvents for 24 hours at room temperature and had solvent resistance without volume expansion and tissue destruction of the continuous porous body.

The microscope picture of Example 3 is shown. The microscope picture of the comparative example 2 is shown.

Claims (10)

A cotton swab comprising a shaft portion and a contact portion provided at the tip of the shaft portion, wherein the contact portion is made of a hydrophilic continuous porous body formed of an olefin-based thermoplastic resin. Cotton swab. After the hydrophilic continuous porous body is molded by kneading at least a pore forming agent into an olefinic thermoplastic resin, at least a part of the obtained molded product is immersed in a liquid having a temperature higher than the melting point of the resin, Next, the shape pore agent is eluted with an aqueous solvent to obtain a continuous porous body, and then the continuous porous body is impregnated with a solution containing a surfactant and dried. The cotton swab according to claim 1. After the hydrophilic continuous porous body is molded by kneading at least a pore former and a pore assistant in an olefinic thermoplastic resin, at least a part of the resulting molded product has a temperature higher than the melting point of the resin. Some are obtained by immersing in a liquid, then elution of the pore with an aqueous solvent to obtain a continuous porous body, and then impregnating the continuous porous body with a solution containing a surfactant and drying it. The cotton swab according to claim 1. After the hydrophilic continuous porous body is molded by kneading at least a pore forming agent, a pore auxiliary agent and a surfactant into an olefinic thermoplastic resin, at least a part of the obtained molded product is melted by the melting point of the resin. It is obtained by immersing in a liquid at a higher temperature, then eluting the shape pore with an aqueous solvent to obtain a continuous porous body, then impregnating the continuous porous body with a solution containing a surfactant and drying it. The cotton swab according to claim 1, wherein the cotton swab is provided. The hydrophilic continuous porous body is molded by kneading at least a pore former, a pore assistant and a surfactant into an olefinic thermoplastic resin, and then immersed in a liquid having a temperature higher than the melting point of the resin, 2. The swab according to claim 1, wherein the swab is obtained by eluting the pore with an aqueous solvent. The swab according to any one of claims 1 to 5, wherein the olefinic thermoplastic resin is at least one selected from the group consisting of ethylene vinyl acetate copolymer, polyethylene, and polypropylene. The swab according to any one of claims 2 to 5, wherein the pore forming agent is a water-soluble organic substance not containing metal ions. The swab according to any one of claims 3 to 5, wherein the pore-forming aid is a polyhydric alcohol monomer or polymer. The cotton swab according to any one of claims 1 to 8, which is used for medical purposes. The cotton swab according to any one of claims 1 to 8, which is used for makeup.

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