JP2020110292A - Columnar body manufacturing method and cosmetic sponge manufacturing method - Google Patents

Abstract

To provide a columnar body manufacturing method that can be used when efficiently manufacturing a cosmetic sponge having good flexibility and texture by reducing a surplus portion to be disposed in the molding, and provide a cosmetic sponge manufacturing method using the columnar body obtained.SOLUTION: A columnar body manufacturing method is used for manufacturing a cosmetic sponge. The columnar body manufacturing method has a step of adjusting a resin composition 50 containing polyurethane, water-soluble inorganic particles and a water-soluble organic solvent; a step of kneading the resin composition; a step of putting the resin composition in the mold 10, and molding it as a column shape; and a step of immersing the resin composition in a solidifying solution L based on water together with the mold to obtain a columnar body 60. The mold has an inner wall surface coming in contact with the bottom surface of the columnar body. The inner wall surface has a shape congruent with the bottom surface of the cosmetic sponge, or formed by enlarging the bottom surface in a similar figure.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a columnar body and a method for manufacturing a cosmetic sponge.

BACKGROUND ART Conventionally, a porous body using polyurethane as a forming material has been suitably used as a cosmetic sponge or a cosmetic puff.

As a method for producing a porous body of polyurethane, a resin composition in which polyurethane and water-soluble particles are dispersed in a water-soluble organic solvent is desolvated in a coagulation liquid containing water as a main component to coagulate, There is known a method of eluting and removing water-soluble particles from the formed body (Patent Documents 1 and 2). According to this method, it is possible to form a three-dimensional network structure in the obtained molded product and to impart flexibility and good touch to the skin.

JP 2001-233987 A JP, 2011-225807, A

Conventionally, the above-described resin composition has been molded into a sheet and then punched out using a predetermined mold to form a desired cosmetic sponge.

However, as described above, in a series of molding steps for punching a porous body processed into a sheet shape, an excess portion when processing the porous body into a sheet shape, an excess portion after punching occurs, and a large amount of waste is generated. There was a drawback.

The present invention has been made in view of the above circumstances, and a column which can be used when efficiently producing a cosmetic sponge having good flexibility and softness by reducing the excess portion to be discarded at the time of molding An object is to provide a method for manufacturing a body. Another object is to provide a method for producing a cosmetic sponge using the obtained columnar body.

In order to solve the above problems, one embodiment of the present invention is a method for producing a columnar body used for producing a cosmetic sponge, comprising polyurethane, water-soluble inorganic particles, and a water-soluble organic solvent. A step of adjusting the resin composition, a step of kneading the resin composition, a step of molding the resin composition into a mold, and molding into a columnar shape, the resin composition containing water as the main component together with the mold. Dipped in a coagulating liquid to obtain a columnar body, the mold has an inner wall surface in contact with the bottom surface of the columnar body, the inner wall surface is congruent with the bottom surface of the cosmetic sponge, Alternatively, there is provided a method of manufacturing a columnar body having a shape in which the bottom surface is enlarged in a similar shape.

In one aspect of the present invention, the side wall of the mold may have a plurality of through holes that connect the outer surface of the side wall and the inner surface of the side wall.

In one aspect of the present invention, the mold may be a manufacturing method having a closed space surrounded by the inner surface.

In one aspect of the present invention, the manufacturing method may be such that the temperature of the coagulating liquid is 50° C. or lower.

In one aspect of the present invention, the step of obtaining the columnar body includes a step of immersing the resin composition in the coagulation liquid, and a step of immersing the obtained coagulation product in water at a temperature higher than 50°C. It may be a method.

In one aspect of the present invention, a manufacturing method may include a step of defoaming the resin composition after the step of kneading the resin composition and prior to the step of molding into the columnar shape.

Further, one aspect of the present invention provides a method for producing a cosmetic sponge, which includes the method for producing a columnar body described above and a step of cutting the obtained columnar body into a plurality of pieces in parallel with the bottom surface of the columnar body. ..

According to the present invention, a method for producing a columnar body that can be used when producing a cosmetic sponge that effectively reduces the excess portion to be discarded during molding and that has good flexibility and soft touch, and It is possible to provide a method for producing a cosmetic sponge using the obtained columnar body.

It is explanatory drawing explaining the manufacturing method of a columnar body, and the manufacturing method of a cosmetic sponge. It is explanatory drawing explaining the manufacturing method of a columnar body, and the manufacturing method of a cosmetic sponge. It is explanatory drawing explaining the manufacturing method of a columnar body, and the manufacturing method of a cosmetic sponge. 7 is a cross-sectional view of a resin molded body obtained in Comparative Example 1. FIG. 5 is a schematic diagram showing a mold 20 used in Example 2. FIG.

Hereinafter, the present invention will be described in detail.

<Method for producing columnar body, method for producing cosmetic sponge>
The method for producing a columnar body according to the present embodiment is a method for producing a columnar body used for producing a cosmetic sponge, which is a resin composition containing polyurethane, water-soluble inorganic particles, and a water-soluble organic solvent. A step of adjusting a product, a step of kneading the resin composition, a step of putting the resin composition in a mold and molding it into a column, and a resin composition containing the mold together with a water-based coagulating liquid as a main component. Immersing in, and obtaining a columnar body, the mold has an inner wall surface in contact with the bottom surface of the columnar body, the inner wall surface is congruent with the bottom surface of the cosmetic sponge, or the bottom surface Is a shape enlarged to a similar shape.

The method for manufacturing a cosmetic sponge according to the present embodiment includes the method for manufacturing a columnar body described above, and a step of cutting the obtained columnar body into a plurality of pieces in parallel with the bottom surface of the columnar body.

In the present specification, the term "cosmetic sponge" refers to a porous member used during makeup and generally called a sponge or puff. In this sense, for example, a porous member used for applying cosmetics to human skin at the time of makeup regardless of the difference in the properties of the cosmetics such as liquid foundation (liquid foundation) and powder foundation (powder foundation). Corresponds to a "cosmetic sponge".

Furthermore, the sponge used for washing the face also corresponds to the "cosmetic sponge".

(Polyurethane)
The polyurethane used in the production method of the present embodiment is obtained by polyaddition of a compound having a plurality of isocyanate groups and a compound having two or more hydroxyl groups (polyol component). In the polyurethane used in the production method of the present embodiment, as the polyol component, polyether polyol, polyester polyol and polycarbonate polyol can be used alone or in combination of two or more kinds.

It is preferable to use at least a polyether polyol as the polyol component, and it is more preferable to use the polyether polyol alone. It is preferable that the polyurethane contains a hydrophilic polyether polyol because a cosmetic sponge having a very slimy feeling can be obtained.

In addition, in the present specification, “slickness” means a soft and supple feel that has flexibility and suppleness around the skin when it comes into contact with human skin and is smooth and adsorbed on the skin.

(Inorganic particles)
The inorganic particles used in the manufacturing method of the present embodiment are not limited as long as they are water-soluble. Examples of the material for forming such inorganic particles include water-soluble inorganic salts such as anhydrous sodium sulfate, potassium sulfate, sodium chloride, potassium chloride, calcium chloride, sodium bicarbonate, sodium carbonate and potassium carbonate. These inorganic particles may be used alone or in combination of two or more.

It is preferable to use anhydrous sodium sulfate as the inorganic particles because the obtained cosmetic sponge tends to have good flexibility and softness.

As for the shape and particle size of the inorganic particles, any shape and particle size can be used as long as they do not depart from the spirit of the invention.

For example, the particle shape of anhydrous sodium sulfate differs depending on the manufacturing method. Commercially available anhydrous sodium sulfate has a rugby ball-like particle shape and an amorphous particle shape. Any of them can be used in the method for manufacturing the columnar body of the present embodiment.

The average particle size of anhydrous sodium sulfate is preferably 5 to 500 μm, more preferably 15 to 300 μm.
In the present embodiment, the average particle size of anhydrous sodium sulfate means the arithmetic mean value of the particle sizes measured by the sieving method.

(Organic solvent)
Examples of the water-soluble organic solvent used in the production method of the present embodiment include amide solvents such as N,N-dimethylformamide (DMF), alcohol solvents such as 2-propanol, and ketone solvents such as methyl ethyl ketone. You can These organic solvents may be used alone or as a mixed solvent in which two or more kinds are mixed. As the water-soluble organic solvent, DMF is preferable because it has a high solubility in polyurethane and can be easily desolvated with water in a subsequent step.

(Process of adjusting resin composition)
In the method for manufacturing the columnar body of the present embodiment, first, a resin composition containing polyurethane, water-soluble inorganic particles, and a water-soluble organic solvent is prepared. In that case, for example, the inorganic particles and the organic solvent may be added to a polyurethane solution which is commercially available with a solid content of about 25 to 35% by mass and stirred.

For example, with respect to 100 parts by mass of a polyurethane solution that is commercially available with a solid content of 30% by mass, the organic solvent is 5 to 40 parts by mass, the inorganic particles are 100 to 1000 parts by mass, and preferably 150 to 800 parts by mass. It is preferable to adjust the resin composition by adding the above.

In addition, components such as a colorant, a surfactant, a deterioration inhibitor, and an antibacterial agent may be added to the resin composition as needed, as long as the effects of the invention are not impaired.

(Step of kneading the resin composition)
Then, the resin composition is kneaded. For kneading the resin composition, it is preferable to use a device such as a kneader, a propeller mixer, a ribbon mixer, a single-screw extruder, or a twin-screw extruder that can easily stir even if it has high viscosity.

(Step of defoaming)
Next, it is preferable to include a step of defoaming the kneaded resin composition.

The specific method of defoaming is not limited as long as it is a method of removing bubbles in the composition. For example, a method of leaving it under a reduced pressure condition, a method of forcibly removing air bubbles using a centrifuge or the like can be mentioned. Further, when the resin composition is filled in a mold described later, a vent type extruder or the like may be used for defoaming at the same time as filling.

After kneading, the bubbles contained in the resin composition may cause huge pores in the obtained resin molded body. Such huge pores may cause a decrease in the flexibility of the cosmetic sponge and a deterioration in the touch when the cosmetic sponge is prepared. Therefore, by degassing the resin composition after kneading, it is possible to suppress the formation of the huge pores.

The resin composition after kneading may be defoamed by allowing the resin composition to stand for a certain period of time without forcibly defoaming it by the method described above.

(Molding process)
Then, the resin composition is put into a mold and molded into a columnar shape.

Here, the “columnar shape” refers to a shape surrounded by a bottom surface, a side surface formed by a straight line orthogonal to the bottom surface along a contour of the bottom surface, and an upper surface facing the bottom surface. The distance between the bottom surface and the top surface is the “height” of the columnar solid. The bottom surface and the top surface are preferably parallel to each other.

FIG. 1 is an explanatory diagram illustrating this step.

The mold 10 shown in FIG. 1 is a rectangular parallelepiped container having an open top. The mold 10 has sidewalls 10a and 10b facing each other, sidewalls 10c and 10d orthogonal to the sidewalls 10a and 10b, and a bottom portion 10e orthogonal to the sidewalls 10a to 10d. The inner surface of the side wall 10a or the side wall 10b corresponds to the "inner wall surface" of the present invention.

Further, the mold 10 has an internal space 10x surrounded by the side walls 10a to 10d and the bottom portion 10e.

The inner surfaces of the side walls 10a and 10b of the mold 10 are shaped to be the same as the bottom surface of the cosmetic sponge that is the object, or a shape in which the bottom surface of the cosmetic sponge is enlarged in a similar shape.

The length of the inner surfaces of the side walls 10c and 10d of the mold 10 in the longitudinal direction is larger than the thickness of the target cosmetic sponge.

The “bottom surface of the cosmetic sponge” refers to the surface of the cosmetic sponge that faces the largest surface of the rectangular parallelepiped when the rectangular parallelepiped in contact with the cosmetic sponge is assumed.

The material of the mold is not particularly limited, and metal, plastic, wood, etc. can be used. It is preferable to use stainless steel that does not cause rust, polypropylene that does not soften or deform at bath temperature, polyethylene terephthalate (PET), plastic such as polytetrafluoroethylene.

In addition, it is more preferable that the inner surface of the mold is demolded so that it can be easily removed from the mold without breaking the shape of the resin molded body obtained by solidifying in the step described below.

When the resin composition 50 is filled in the internal space 10x of the mold 10, the resin composition 50 shaped like a column in the mold 10 is obtained. That is, in the columnar resin composition 50, the surfaces facing the inner surfaces of the side walls 10a and 10b have a shape that is congruent or enlarged in a similar shape to the bottom surface of the cosmetic sponge that is the target. Further, the height of the columnar resin composition 50 is larger than the thickness of the target cosmetic sponge.

A general cosmetic sponge has a bottom surface having a shape such as a circle, an ellipse, and a quadrangle with rounded four corners, a top surface that is congruent and parallel to the bottom surface, and a side surface that is continuous with the bottom surface and the top surface. It has a three-dimensional shape surrounded by. The distance between the bottom surface and the top surface of the makeup sponge is about 1 to 15 mm.

In this step, a mold 10 is used in which the obtained columnar resin composition 50 has a bottom surface and an upper surface that are shaped to be the same as or similar to the bottom surface of the cosmetic sponge that is the target. As will be described later, when a resin molded body obtained from the columnar resin composition 50 is subjected to processing such as chamfering or side surface polishing, the volume removed by the processing is taken into consideration, and the molded body is as large as removed. It is preferable to use a mold that can obtain

In the conventional method of extruding a resin composition from an extrusion molding machine connected to a molding die port and shaping the resin composition, the fluidity of the composition is increased until the resin composition is solidified in the solidifying step described later. Or the self-weight may cause the shaped shape to collapse. On the other hand, when the resin composition is shaped using a mold as in the manufacturing method of the present embodiment, the shape of the resin composition can be maintained until the subsequent steps.

Since the shape of the shaped resin composition 50 is further prevented from being deformed and the bottom surface of the cosmetic sponge can be molded even if it has a curved line or a complicated polygonal shape, the mold has a space surrounded by the entire inner surface. It is preferably formed. When the resin composition is shaped using such a mold, the resulting columnar resin composition is surrounded by the mold on the entire circumference.

When such a mold is used, it is preferable that the mold has a plurality of through holes that connect the outer surface of the side wall of the mold and the inner surface of the side wall so as not to interfere with the solidification step described later. In the step described below, the organic solvent and the inorganic particles contained in the resin composition are discharged through the through holes, and a columnar resin molded body is obtained.

The through holes formed in the mold are not particularly limited as long as the effects of the invention are not impaired, that is, the shape of the columnar resin composition is not deviated from the purpose of preventing deformation of the resin composition. Not done. For example, circular holes may be arranged in a zigzag pattern in a plane, square or rhombic holes may be arranged in a matrix, or irregular holes may be irregularly arranged. Further, the shape, size, number of per-unit area, etc. of the through holes may be the same or different in the entire mold. For example, the shape and size of the through hole, the number per unit area, and the like may be changed between the bottom surface and the side surface of the mold.

When the ratio of the total area of the through holes to the area of the side wall of the virtual mold having no through holes is defined as the opening ratio, the opening ratio is preferably 5 to 50%, more preferably 10 to 35%. If the opening ratio of the mold is less than 5%, the extraction of the organic solvent and the inorganic particles from the resin composition may be delayed and the productivity may be reduced. On the other hand, when the opening ratio of the mold exceeds 50%, the resin composition is likely to lose its shape.

When a mold having through holes is used, the viscosity of the resin composition is adjusted so as not to easily flow out from the through holes. The viscosity can be adjusted by reducing the amount of organic solvent used and increasing the solid content concentration. If the resin composition has the composition described in the step of adjusting the resin composition, good molding can be achieved even when a mold having a through hole is used.

(Process of obtaining a resin molded body)
Next, the columnar resin composition shaped by the mold is immersed in a coagulating liquid containing water as a main component together with the mold. As a result, the organic solvent is removed from the columnar resin composition, and the resin composition is solidified. This operation corresponds to the "step of immersing in the coagulating liquid" in the present invention.

FIG. 2 is an explanatory diagram illustrating this step.

The resin composition 50 shaped by the mold 10 is immersed in the coagulating liquid L stored in the tank 100 together with the mold 10. In the coagulation liquid L, the water-soluble organic solvent is removed from the resin composition 50, and the water-insoluble resin remains in the mold 10 and coagulates. Thereby, the columnar resin molded body 60 can be obtained while maintaining the shape of the resin composition 50 shaped in the mold 10. The “resin molded body 60” corresponds to the “columnar body” in the present invention.

At the same time, inorganic particles are extracted from the resin composition 50. When the water-soluble inorganic particles are extracted from the resin composition 50, the obtained resin molded body 60 becomes a porous body having a three-dimensional network structure.

As the coagulation liquid L, an aqueous solution containing a total of 0 to 40% by mass, preferably 0 to 20% by mass of a water-soluble inorganic salt that is a material for forming inorganic particles and a water-soluble organic solvent such as DMF is used.

The temperature of the coagulating liquid L is preferably 50°C or lower, and more preferably 40°C or lower. If the solidification is performed at a temperature higher than 50° C., the speed of the organic solvent removed from the resin composition 50 becomes too fast, and undesired huge pores may be generated in the obtained resin molded body 60. When such voids are formed in the resin molded body 60, there is a possibility that the flexibility and the touch may deteriorate when used as a cosmetic sponge.

By setting the temperature of the coagulating liquid L to 50° C. or lower, the pores are formed while appropriately controlling the rate of the organic solvent removed from the resin composition 50, and the resin molded body 60 having a dense three-dimensional network structure is obtained. Obtainable.

The rate of the organic solvent removed from the resin composition 50 can be adjusted by mixing the coagulation liquid L with an appropriate amount of a water-soluble organic solvent.

The extraction rate of the inorganic particles from the resin composition 50 can be adjusted by mixing the coagulation liquid L with an appropriate amount of a water-soluble inorganic salt that is a material for forming the inorganic particles.

The time for immersing the columnar resin composition 50 in the coagulation liquid L is preferably 15 minutes to 144 hours, more preferably 90 minutes to 96 hours. If the immersion time is less than 15 minutes, the resin composition 50 may not be sufficiently solidified, and the fluidity or the weight may cause the mold to lose its shape. If the immersion time exceeds 144 hours, the productivity will be significantly impaired.

The resin molded body 60 obtained by solidifying the resin composition 50 uses a normal pressure washer, a jet dyeing machine, a washing machine, etc., if necessary, according to a standard method, and with water at 0 to 90° C. for about 10 minutes to 3 hours. , Stirring and washing may be performed. By such an operation, the inorganic particles remaining in the resin molded body 60 can be more carefully extracted.

In order to sufficiently extract the inorganic particles from the resin molded body 60, when extracting the inorganic particles from the resin molded body 60, the resin molded body 60 may be deformed by rubbing or the like. On the other hand, since the resin molded body 60 is very soft, if the resin molded body 60 is deformed while many inorganic particles remain inside the resin molded body 60, the three-dimensional network structure is broken and voids are connected. However, there is a possibility that unfavorable huge pores may be formed in the resin molded body 60. In order to suppress the generation of huge pores, when the inorganic particles are sufficiently extracted while deforming the resin molded body 60, the resin molded body 60 is sufficiently immersed in the coagulating liquid L to ensure that the inorganic particles are sufficiently dispersed. It is good that it is done after extraction. Also in that case, the amount of deformation of the resin molded body 60 may be appropriately adjusted so that huge holes are not generated.

The columnar resin composition 50 described above has a smaller surface area than when the resin composition of the same volume is stretched into a sheet. Therefore, when the resin composition 50 is immersed in the coagulation liquid L, the distance from the surface in contact with the coagulation liquid L to the center of the columnar resin composition 50 becomes longer than that of the resin composition shaped into a sheet. Therefore, when the columnar resin composition 50 is solidified, a longer immersion time is required for extracting the inorganic particles than the sheet-shaped resin composition.

In the present embodiment, the resin molded body 60 that has been solidified may be immersed in high temperature water. Specifically, after the resin composition 50 is solidified in a coagulating liquid containing water as a main component and having a temperature of 50° C. or lower, the resin composition 50 is immersed in water having a temperature of higher than 50° C. This operation corresponds to the “step of immersing in water having a temperature higher than 50° C.” in the present invention.
In the following description, the "water having a temperature exceeding 50°C" used in the above operation is referred to as a "cleaning liquid".

Regarding the completion of the solidification of the resin molded body 60, the fact that the resin composition 50 being solidified is pressed with a finger and then the finger is released from the resin composition 50 repels the original shape (pressed with the finger). The judgment is made by returning to the previous shape of the resin composition 50).

After the organic solvent is sufficiently extracted and the resin molded body 60 is solidified, the resin molded body is accelerated even if the extraction speed of the inorganic particles is increased, except when the resin molded body 60 is largely deformed to break the three-dimensional network structure. The voids inside 60 do not grow. Therefore, after the resin composition 50 is solidified in a coagulation liquid containing water as a main component and having a temperature of 50° C. or less, the resin molding 60 is immersed in a cleaning liquid to form a large void in the resin molding. Generation can be suppressed and the time required for extracting the inorganic particles can be shortened. Therefore, the inorganic particles can be more thoroughly extracted, and the extraction speed can be increased and the productivity can be increased while maintaining the flexibility and the feel suitable as a cosmetic sponge.

It should be noted that sufficient extraction of the inorganic particles from the resin molded body 60 can be determined by sampling a part of the sample from the resin molded body 60 in the middle of washing and floating it on water. When the sample floats on water, the density of the resin molded body 60 is relatively smaller than that of water, and it can be determined that the inorganic particles have been sufficiently extracted from the resin molded body 60. When the sample sinks in water, a large amount of inorganic particles having a higher density than water remain in the sample, and it can be determined that the extraction of the inorganic particles from the resin molded body 60 is insufficient. ..

It is preferable that the cleaning liquid does not contain an organic solvent other than that brought in from the resin molded body 60. When the resin molded body 60 is dipped in a liquid having an organic solvent and having a temperature higher than 50° C., the three-dimensional network structure generated by being removed from the organic solvent during the step of immersing in the coagulating liquid L is redissolved, This may lead to a decrease in flexibility and feel.

When the coagulating liquid L used for coagulating the resin composition 50 does not include a water-soluble organic solvent at the beginning of the step of obtaining the resin molded body, the resin composition 50 is sufficiently coagulated and then the coagulating liquid is obtained. The inorganic particles may be extracted by raising the temperature of L to a temperature of more than 50° C. and using it as a cleaning liquid. The productivity is improved by raising the temperature of the coagulating liquid L to form the cleaning liquid, as compared with the operation of separately obtaining the resin molding 60 from the coagulating liquid L and the cleaning liquid.

As described above, when water is used as the coagulating liquid L, the coagulating liquid L having a volume of 2.5 times or more that of the resin composition 50 to be coagulated is preferably used for coagulation. In this case, it is desirable to control the concentration of the organic solvent contained in the coagulation liquid L with respect to the entire coagulation liquid L to be 0.8% by mass or less. In controlling the concentration of the coagulating liquid L, a method is employed in which water is added to the bath 100 while a part of the coagulating liquid L is withdrawn from the bath 100 storing the coagulating liquid L to control the concentration of the coagulating liquid L in the bath 100. be able to.

The time of immersion in the cleaning liquid is preferably 15 minutes to 144 hours, more preferably 90 minutes to 96 hours. If the immersion time is less than 15 minutes, the inorganic particles may not be sufficiently extracted from the resin molded body 60, and if it exceeds 144 hours, the productivity is significantly impaired.

After extraction of the inorganic particles by immersion in a cleaning liquid, the cleaning step using a normal pressure washer or the like may be performed if necessary.

Further, after the extraction of the inorganic particles, the resin molded body 60 may be dehydrated by using a known dehydrator such as a centrifugal dehydrator or a mangle roll if necessary.

Then, the resin molded body from which the inorganic particles have been removed is dried at 130° C. or lower using a known dryer such as a tenter type, a shrink type, or a tumbler type.

(Process to cut into multiple pieces)
Next, the columnar resin molded body is cut into a plurality of pieces in parallel with the bottom surface of the resin molded body. FIG. 3 is an explanatory diagram illustrating this step.

The bottom surface 60a of the resin molded body 60 is a shape that is congruent with the bottom surface of the cosmetic sponge, which is the object, or an enlarged shape of the bottom surface of the cosmetic sponge. Therefore, by cutting the resin molded body 60 parallel to the bottom surface 60a, the target cosmetic sponge 70 can be manufactured.

Such a manufacturing method can omit the step of punching a cosmetic sponge from a molded polyurethane product which has been processed into a sheet-like shape by using a predetermined mold as in the conventional method, and also has an excess when processing into a sheet-like shape. There is an advantage that a surplus portion after punching does not occur.

Further, when a cosmetic sponge is punched out from a molded polyurethane product that has been processed into a sheet shape as in the conventional case using a predetermined mold, when a cosmetic sponge having a different thickness is to be produced, the sheet-shaped polyurethane sponge Since it was necessary to change the thickness of the molded body, waste was likely to occur. On the other hand, according to the manufacturing method of the present embodiment, the thickness of the cosmetic sponge 70 can be appropriately changed only by changing the thickness when the columnar resin molded body is cut, and waste is less likely to occur.

If necessary, the outer surface of the resin molded body or the outer edge portion of the cosmetic sponge obtained by cutting the resin molded body in parallel with the bottom surface may be subjected to a process for adjusting the shape. Specifically, a resin molding or a cosmetic sponge may be subjected to necessary processing such as polishing for removing parting lines and surface irregularities, size adjustment, and chamfering.

According to the method for manufacturing a columnar body as described above, it is possible to efficiently manufacture a cosmetic sponge having good flexibility and touch, while reducing the excess portion to be discarded during molding.

Further, according to the method for producing a cosmetic sponge as described above, it is possible to efficiently produce a cosmetic sponge having a good flexibility and a good touch by reducing an excess portion to be discarded at the time of molding.

Hereinafter, the present invention will be specifically described with reference to examples.
In each example, “part” means “part by mass” and “%” means “% by mass”.

<Evaluation 1>
(Example 1)
In Example 1, a cosmetic sponge having a length of 50 mm, a width of 50 mm, and a thickness of 6 mm was manufactured as a target product.

A resin composition was prepared by mixing 100 parts of polyurethane (Krisbon 1836P, manufactured by DIC Corporation, solid content: 30%) whose polyol component is a polyether polyol, 400 parts of anhydrous sodium sulfate, and 20 parts of DMF.

Anhydrous sodium sulfate corresponds to the “water-soluble inorganic particles” in the present invention.
DMF corresponds to the "water-soluble organic solvent" in the present invention.

Then, the obtained resin composition was agitated and kneaded with a kneader (model number: NES KNZ-100-5, manufactured by Chemical Engineering Co., Ltd.) at a rotation speed of 20 rpm for 10 minutes. After that, the resin composition was vacuum defoamed without stirring to remove the air bubbles mixed in the resin composition.

Then, the resin composition prepared as described above was filled in a mold having a rectangular parallelepiped body made of SUS304 and having an inside dimension of length 1210 mm×width 50 mm×depth 50 mm, the top of which is open-molded on the surface. .. At that time, the composition rising from the upper part of the mold was scraped off to flatten the upper surface of the resin composition.

Then, the resin composition filled in the mold was immersed in water adjusted to 55° C. for 40 hours together with the mold to solidify the resin composition to obtain a solidified product. In this operation, water-soluble inorganic particles were also extracted.

Then, the coagulated product was removed from the mold, and washed with water at 30° C. for 2 hours by rubbing with a washer. The solidified product was taken out from the washer and dried in a dryer at 110° C. for 30 minutes to obtain a resin molded product having a length of 1210 mm×a width of 50 mm×a height of 50 mm in which inorganic particles were sufficiently extracted.

By slicing the obtained resin molded body in parallel with a 50 mm×50 mm surface at a thickness of 6 mm, 200 cosmetic sponges having a length of 50 mm×a width of 50 mm×a thickness of 6 mm were obtained.

When the obtained cosmetic sponge was actually used, it was excellent in flexibility and touch.

(Comparative Example 1)
In Comparative Example 1, a cosmetic sponge having a length of 50 mm, a width of 50 mm, and a thickness of 6 mm was manufactured as a target.

The resin composition prepared and kneaded by the procedure described in Example 1 was extruded and shaped while defoaming under reduced pressure using a vent type extruder (model number: DE-3NK, manufactured by Honda Iron and Steel Co., Ltd.). The vent type extruder used was connected to the discharge port with a gold port having an inner width of 50 mm and a height of 50 mm. The preset temperature of the extruder was set to 40° C., and the resin composition was extruded by a length of 1210 mm to obtain a resin composition shaped in a rectangular parallelepiped.

The resin composition obtained was dipped in water adjusted to 55° C. for 40 hours while being placed on a mounting plate, and the resin composition was solidified to obtain a solidified product. Thereafter, the coagulated product was washed and dried in the same manner as in Example 1 to obtain a columnar resin molded body.

FIG. 4 is a cross-sectional view of the obtained resin molded body. FIG. 4 shows a cross-sectional shape parallel to the bottom surface of the columnar resin molded body. In the figure, the broken line shows the cross-sectional shape of the resin composition 55 shaped by the method described above.
In the obtained resin molded body 65, the width of the lower surface 65a was 50 mm and remained unchanged, but the height was crushed to 45 mm by its own weight, and the side surface 65b was swollen outward.

The resin molded body 65 was sliced in parallel with the lower surface 65a so as to have a thickness of 6 mm and cut into 7 sheets. The obtained sheet was punched with a mold having an inner size of 50 mm in length×50 mm in width to obtain a cosmetic sponge of 50 mm in length×50 mm in width×6 mm in thickness. A total of 119 cosmetic sponges were obtained from 1 to 17 sheets and 7 sheets in total.

In Example 1, since the resin molded body in which the shape formed in the resin composition was accurately maintained was obtained, the makeup excellent in flexibility and touch was obtained only by slicing in parallel with the bottom surface of the columnar resin molded body. I was able to obtain a sponge.

On the other hand, in Comparative Example 1, it was necessary to perform a molding process of slicing the resin molded body into a sheet shape and punching the obtained sheet into the target shape due to the shape deformation of the resin composition after shaping. ..

In addition, in Example 1, it was possible to obtain about 1.68 times as many products as in Comparative Example 1 from the same volume of the resin composition.

<Evaluation 2>
(Example 2)
FIG. 5 is a schematic view showing the mold 20 used in Example 2.

The prepared mold 20 has two semi-cylindrical main bodies 21 and 22 and two lids 23 and 24 corresponding to the bottom surfaces of the cylinders. The two body portions 21 and 22 are connected by hinges 25 and 26 provided along a cylindrical generatrix. One lid 23 is fixed to the end 21 a of the main body 21. The other lid 24 is attachable to and detachable from the end portions 21b and 22b of the body portions 21 and 22. The inner surface of the lid 23 or 24 corresponds to the "inner wall surface" in the present invention.

The forming material of the main body and the lid is a semi-cylindrical punching metal made of SUS304 and has through holes (through hole diameter: 1 mm, center-to-center distance: 2 mm, 60° staggered arrangement, aperture ratio). : 22%).

When the two body parts 21 and 22 and the two lids 23 and 24 are closed, the mold 20 becomes a cylindrical shape having an inner length of 1210 mm and a diameter of 52 mm. The internal space 20x of the mold 20 is divided into a columnar shape by the body portions 21 and 22 and the lids 23 and 24.

The lid 24 of the mold 20 was removed, and the lid 23 was erected vertically so that the lid 23 was located above. The resin composition prepared and kneaded in the same manner as in Example 1 was filled from the other end portions 21b and 22b of the main body portions 21 and 22 using a vent type extruder. The set temperature of the extruder was 40°C. The filling of the resin composition was performed using a vent type extruder while defoaming under reduced pressure.

The mold 20 filled with the resin composition had the lid 24 closed, and was immersed in water (coagulating liquid) adjusted to 35° C. for 24 hours. In this way, the resin composition was solidified into a columnar resin molded body.

Then, the water temperature was heated to 55° C., and the immersion was continued for 24 hours while maintaining the water temperature at 55° C. Thereby, the inorganic particles were sufficiently extracted from the resin molded body.

Then, the mold 20 was opened and the resin molded body was taken out from the mold 20. After washing the surface of the resin molded body with water, it was dried in a dryer at 110° C. for 30 minutes to obtain a resin molded body having a length of 1210 mm and a diameter of 52 mm in which inorganic particles were sufficiently extracted.

After the parting line formed on the side surface of the resin molded body and the projections derived from the through holes of the mold 20 are ground with a grinder, 6 mm each in parallel with the surface (bottom surface) of the resin molded body formed in contact with the lid 23. By slicing to a thickness of 200, 200 cosmetic sponges having a diameter of 50 mm and a thickness of 6 mm were obtained.

When the obtained cosmetic sponge was actually used, the flexibility and the touch were very excellent.

(Example 3)
A mold having a length of 1210 mm and a diameter of 52 mm was prepared in the same manner as in Example 2 except that the mold filled with the resin composition was not immersed in water adjusted to 35° C. and immersed in water adjusted to 55° C. for 48 hours. A polyurethane resin molding was obtained.

The periphery of the molded body was polished in the same manner as in Example 2, and sliced in parallel with the bottom surface to have a thickness of 6 mm, to obtain 200 cosmetic sponges having a diameter of 50 mm and a thickness of 6 mm.

When the obtained cosmetic sponge was actually used, it was excellent in flexibility and touch.

(Example 4)
In the same manner as in Example 2, the resin composition was filled in a mold and immersed in water adjusted to 48° C. for 48 hours to coagulate the resin composition, and inorganic particles were extracted to obtain a coagulated product.

Then, the hinge was opened and the coagulated product was taken out from the mold, and washed with water at 30° C. for 2 hours with a normal pressure washer. The coagulated product was taken out from the atmospheric washer and dried in a dryer at 110° C. for 30 minutes to obtain a polyurethane resin molded body having a length of 1210 mm and a diameter of 52 mm.

The periphery of the molded body was polished in the same manner as in Example 2, and sliced in parallel with the bottom surface to have a thickness of 6 mm, to obtain 200 cosmetic sponges having a diameter of 50 mm and a thickness of 6 mm.

When the obtained cosmetic sponge was actually used, it was excellent in flexibility and touch.

(Example 5)
A mold having a length of 1210 mm and a diameter of 52 mm was prepared in the same manner as in Example 2 except that the mold filled with the resin composition was not immersed in water adjusted to 35° C., and was immersed in water adjusted to 48° C. for 72 hours. A polyurethane resin molding was obtained.

The periphery of the molded body was polished in the same manner as in Example 2, and sliced in parallel with the bottom surface to have a thickness of 6 mm, to obtain 200 cosmetic sponges having a diameter of 50 mm and a thickness of 6 mm.

When the obtained cosmetic sponge was actually used, the flexibility and the touch were very excellent.

The results of Examples 2 to 5 are shown in Table 1 below. In the evaluation column, the results of evaluation of the obtained cosmetic sponge according to the following criteria are described.
⊚: Very good in flexibility and touch ◯: Excellent in flexibility and touch ×: At least one of softness and feel in touch

As a result of the evaluation, in Examples 2 and 5 in which coagulation is performed in a coagulation liquid at a temperature of 50° C. or less, and sufficient extraction of the inorganic particles is completed in the immersion step in water, the flexibility and the touch are very high. An excellent cosmetic sponge could be obtained.

Further, in Example 2 in which the inorganic particles were sufficiently extracted by coagulating in a coagulating liquid having a temperature of 50° C. or less and immersing in water (cleaning liquid) having a temperature exceeding 50° C., the coagulating liquid of 48° C. It was possible to shorten the working time as compared with Example 5 in which sufficient extraction of the inorganic particles was completed by.

From the above results, it was found that the present invention is useful.

10, 20... Mold, 10a-10d... Side wall, 50, 55... Resin composition, 60... Resin molding, 60a... Bottom, 70... Cosmetic sponge, L... Coagulating liquid

Claims (7)

A method for manufacturing a columnar body used for manufacturing a cosmetic sponge,
A step of preparing a resin composition containing polyurethane, water-soluble inorganic particles, and a water-soluble organic solvent,
A step of kneading the resin composition,
A step of putting the resin composition in a mold and molding it into a pillar shape,
A step of immersing the resin composition in a coagulating liquid containing water as a main component together with the mold to obtain a columnar body,
The mold has an inner wall surface in contact with the bottom surface of the columnar body,
The method for producing a columnar body, wherein the inner wall surface is congruent with the bottom surface of the cosmetic sponge, or has a shape in which the bottom surface is enlarged in a similar shape. The method for manufacturing a columnar body according to claim 1, wherein the side wall of the mold has a plurality of through holes that connect an outer surface of the side wall and an inner surface of the side wall. The method for manufacturing a columnar body according to claim 2, wherein the mold has a closed space surrounded by the inner surface. The method for manufacturing a columnar body according to claim 1, wherein the temperature of the coagulating liquid is 50° C. or lower. The columnar body according to claim 4, wherein the step of obtaining the columnar body includes a step of immersing the resin composition in the coagulation liquid, and a step of immersing the obtained coagulated product in water at a temperature higher than 50°C. Production method. The method for manufacturing a columnar body according to claim 1, further comprising a step of defoaming the resin composition after the step of kneading the resin composition and prior to the step of molding the resin composition. .. A manufacturing method of the columnar body according to any one of claims 1 to 6,
And a step of cutting the obtained columnar body into a plurality of pieces parallel to the bottom surface of the columnar body.

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