JP7699422B2 - Continuously ventilated sponges and cosmetic puffs - Google Patents

Description

The present invention relates to an open-cell sponge and a cosmetic puff. In particular, it relates to an open-cell sponge that is a mechanically foamed foam and is characterized by its low water absorption rate.

The open-cell sponge, which is one application of the present invention, relates to a cosmetic puff that does not soak up liquid foundation excessively. Conventionally, a method for making it difficult for liquid foundation to soak up into polyurethane sponges used in cosmetic puffs involves mixing a non-reactive silicone-based water repellent material with a polyurethane solution raw material, extruding the mixture, and then applying heat and reduced pressure to evaporate the solvent to obtain a foam (see Patent Document 1).

On the other hand, a water-repellent foam has been proposed in which a prepolymer having a terminal isocyanate group, which is obtained by reacting a monool having 8 or more carbon atoms with an isocyanate compound, is foamed into a slab using a polyol and water as a foaming agent (see Patent Document 2).

Furthermore, a foam has also been proposed in which a polyol made from vegetable oil (castor oil type) and a diphenylmethane diisocyanate (MDI type) isocyanate are foamed by a water foaming method (see Patent Document 3).
In addition, a foam using a polyol having a high rate of primary terminal polyols has been proposed as a mechanical foam obtained by mechanical foaming (mechanical froth method) (see Patent Document 4).

Japanese Patent Application Publication No. 6-284923 JP 2006-89582 A JP 2007-54164 A Patent No. 6106523

Here, the foam obtained by the method of Patent Document 1 uses a silicone-based water-repellent material that does not have a reactive group, so it is easily dissolved when the cosmetic puff is washed with detergent, and the water-repellent properties of the foam are quickly lost. As a result, the liquid absorption rate is high.

Moreover, the foam of Patent Document 2 is water-foamed, so the cells are rough and the feel on the skin is not good.
Moreover, since the foam of Patent Document 3 is also water-foamed and therefore prone to forming closed cells, the cells are intentionally roughened to form open cells, so that fine cells cannot be obtained and the foam does not feel good against the skin.

The mechanical foam of Patent Document 4 is mechanically foamed, but it is mainly made of polypropylene glycol, so it is difficult to obtain fine cells and the liquid absorption rate is too high.

As such, there are no sponges made from conventional foams that have both an appropriate liquid absorption rate and a pleasant feel on the skin. In particular, foams that have an appropriate liquid absorption rate and a pleasant feel on the skin are useful for, for example, cosmetic puffs that reduce the consumption of liquid foundation and require a comfortable feel when applying foundation to the skin, and are currently in high demand.

Therefore, the objective of the present invention is to provide a continuous ventilation type sponge and a cosmetic puff that have an appropriate liquid absorption rate and a pleasant feel on the skin.

The above problem can be solved by the following means:

[1]
a polymer polyol containing 30% by mass or more and 100% by mass or less of a dimer acid polyester polyol based on the total polymer polyol;
Diphenylmethane diisocyanate-based isocyanates,
A foam stabilizer,
A catalyst;
A continuous air permeable sponge comprising a mechanical foam of a composition comprising:
[2]
The continuous ventilation type sponge according to [1], wherein the polymer polyol contains a polymer polyol other than the dimer acid polyester polyol.
[3]
The continuous ventilation type sponge according to [2], wherein the polymer polyol other than the dimer acid polyester polyol is at least one selected from the group consisting of alkylene oxide-added polyether polyols, polylactone polyols, and carboxylic acid ester polyols.
[4]
The continuous ventilation type sponge according to [2] or [3], wherein the mass ratio of the dimer acid polyester polyol to the polymer polyol other than the dimer acid polyester polyol (dimer acid polyester polyol/polymer polyol other than dimer acid polyester polyol) is 30/70 to 80/20.
[5]
5. The continuous breathable sponge according to any one of claims 1 to 4, which has a water absorption rate of 15% or less.
[6]
The continuous ventilation type sponge according to any one of [1] to [5], wherein the composition contains 5 to 50 parts by mass of an inorganic filler per 100 parts by mass of the polymer polyol.
[7]
The continuous ventilation type sponge according to any one of [1] to [6], which has an own skin layer.
[8]
A cosmetic puff having the continuous ventilation type sponge according to any one of [1] to [7].

The present invention provides a continuous ventilation sponge and a cosmetic puff that have a moderate liquid absorption rate and a pleasant feel on the skin.

FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the method of manufacturing a continuous-ventilation sponge according to this embodiment. FIG. 13 is a diagram showing the degree to which liquid foundation is absorbed into the continuous air-permeable sponge of Example 4. FIG. 13 is a diagram showing the degree to which kid foundation is absorbed into the sponge of Comparative Example 7.

The following describes an embodiment of the present invention.

(Continuous ventilation sponge)
The continuous ventilation type sponge according to this embodiment (hereinafter, simply referred to as "sponge") is
a polymer polyol containing 30% by mass or more and 100% by mass or less of a dimer acid polyester polyol based on the total polymer polyol;
Diphenylmethane diisocyanate-based isocyanate (hereinafter also referred to as "MDI-based isocyanate"),
A foam stabilizer,
A catalyst;
The present invention relates to a mechanical foam having a composition comprising:
The composition for forming the foam (hereinafter also referred to as "urethane raw material liquid") may contain other components in addition to the above components.

The continuous ventilation sponge according to this embodiment has the above-mentioned configuration, resulting in a sponge with an appropriate liquid absorption rate and a pleasant feel on the skin. The reason for this is presumed to be as follows. There is a correlation between the liquid absorption rate of liquid foundation and the water absorption rate, and the liquid absorption rate performance can be expressed in terms of water absorption rate.

The mechanical foam obtained by mechanically foaming 30% by mass or more and 100% by mass or less of the total polymer polyol and MDI-based isocyanate using a foam stabilizer and a catalyst becomes a fine, continuous-air-permeable foam due to the use of the dimer acid polyester polyol. The obtained mechanical foam is not only fine and continuous-air-permeable, but also has the property of not excessively absorbing liquid because the dimer acid polyester polyol is hydrophobic due to its molecular structure.

Therefore, it is presumed that the continuous breathable sponge according to this embodiment, due to the above-mentioned configuration, is a sponge with an appropriate liquid absorption rate and a pleasant feel on the skin.
Furthermore, the continuous breathable sponge according to this embodiment can ensure the required mechanical properties such as strength.

For example, when the continuous ventilation type sponge according to this embodiment, which has such characteristics, is used as a makeup puff, the puff not only feels comfortable on the skin, but also does not absorb liquid foundation excessively. This reduces the consumption of liquid foundation and achieves a comfortable application of foundation to the skin. Furthermore, since strength is ensured, durability is also achieved.

The details of the continuous ventilation sponge according to this embodiment are described below.

(polymer polyol)

The details of the continuous ventilation sponge according to this embodiment are described below.

First, let us explain each component of the urethane raw material liquid.

(Polymer polyol)
As the polymer polyol, a dimer acid polyester polyol (hereinafter also referred to as "dimer acid polyester polyol A") is applied. All polyols may be dimer acid polyester polyol A, or dimer acid polyester polyol A may be used in combination with a polymer polyol other than dimer acid polyester polyol (hereinafter also referred to as "polymer polyol B").
By using the polymer polyol B together with the dimer acid polyester polyol A, it becomes possible to add various functions to the sponge, such as lowering the density of the sponge, controlling the liquid absorption property, and improving the solvent resistance.

Here, the high molecular weight polyol means a polyol having a hydroxyl value (OHv) of 250 or less.
The hydroxyl value OHv of the polyol is a value measured in accordance with JIS K1557-1:2007.

-Dimer acid polyester polyol A-
The dimer acid polyester polyol A includes polyester polyols obtained by condensing dimer acid with glycol.
Specifically, for example, the dimer acid polyester polyol A may be a polyester polyol obtained by condensing a dimer acid (b-1) with a low molecular weight diol (b-2), and when it is desired to increase the number of functional groups, a polyester polyol obtained by further condensing a low molecular weight triol (b-3) may be used.

Dimer acid (b-1) is a dibasic acid obtained by bonding two molecules of two monobasic fatty acids together through a carbon-carbon covalent bond, and has twice the molecular weight of the monobasic fatty acid before bonding. Normally, the monobasic fatty acid that constitutes the dimer acid has a fatty acid with about 18 carbon atoms. Representative dimer acid compounds include dibasic acids obtained by heating linoleic acid and oleic acid.

Usually, in the industrial production of dimer acid, monomer acids, tribasic acids, and polymeric acids other than dimer acid are contained as by-products. When producing dimer acid polyester polyol A, it is preferable that the dimer acid has a high purity, but these by-products may be used in a mixed state.

The low molecular weight diol (b-2) is not particularly limited as long as it is a low molecular weight compound and has two -OH groups. The low molecular weight diol refers to a compound having a total carbon number of 2 or more and having 2 to 10 carbon atoms between the two -OH groups, and more preferably has 4 to 6 carbon atoms.
More specifically, suitable examples of the low molecular weight diol (b-2) include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol.

The term "low molecular weight" in the low molecular weight triol (a-3), as in the low molecular weight diol, refers to a hydrocarbon group moiety to which three hydroxyl groups are bonded having a carbon number of 3 to 10, and more preferably a carbon number of 3 to 6. The hydrocarbon group moiety may be linear or branched.
Specific examples of the low molecular weight triol (a-3) include glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, and 2-methylpropanetriol.

The dimer acid polyester polyol A is preferably a polyol that is liquid at room temperature (25° C.) from the viewpoint of forming a fine, open-air type foam by mechanical foaming.
Specifically, the viscosity of the dimer acid polyester polyol at room temperature (25° C.) is preferably 2,000 to 10,000 mP·s.
The viscosity is a value measured by a Brookfield viscometer.

The hydroxyl value OHv of the dimer acid polyester polyol A is preferably 20 to 180 mgKOH/g from the viewpoint of the liquid absorption of the sponge and cell fineness. If the hydroxyl value is 20 or less, the viscosity becomes high, it is difficult to mix gas in by mechanical foaming, and the expansion ratio does not increase, so the density of the foam does not decrease. If the hydroxyl value is 180 or more, the foam obtained becomes hard and has a poor feel to the touch, which is not preferable. In consideration of the ease of mixing gas and the softness of the foam obtained, 50 to 150 mgKOH/g is more preferable.
The hydroxyl value OHv of the polyol is a value measured in accordance with JIS K1557-1:2007.

-High molecular weight polyol B-
Examples of the polymer polyol B include alkylene oxide-added polyether polyols, polylactone polyols, carboxylate polyols, and polycarbonate polyols.

Alkylene oxide-added polyether polyol is a compound obtained by addition polymerization of an alkylene oxide (ethylene oxide, propylene oxide, copolymer of ethylene oxide and propylene oxide, tetramethylene oxide, etc.) to a low molecular weight alcohol (ethylene glycol, glycerin, trimethylolpropane, etc.).
As the alkylene oxide-added polyether polyol, polypropylene glycol (PPG), polyethylene glycol (PEG), a copolymer of PPG and PEG, polytetramethylene ether glycol (PTMG), a copolymer of PTMG and PPG, a copolymer of PTMG and PEG, etc. are preferred, with polytetramethylene glycol being preferred due to its low water absorption.

Examples of the polylactone polyol include polycaprolactone diol, polyvalerolactone diol, and polycaprolactone triol.
Examples of carboxylate polyols include polyols obtained by condensing carboxylic acids (such as adipic acid, sebacic acid, and phthalic acid) with glycols (such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 2-methylpropanediol, and 3-methylpentanediol).
Examples of polycarbonate polyols include polyols obtained by reacting glycol with alkylene carbonate, polyols obtained by reacting glycol with diaryl carbonate, and polyols obtained by reacting glycol with dialkyl carbonate.

Among these, from the viewpoints of high reactivity, improved liquid absorption and texture due to finer cells, as well as increased strength and elongation, the polymer polyol B is preferably at least one selected from alkylene oxide-added polyether polyols, polylactone polyols, and adipate ester polyols, more preferably alkylene oxide-added polyether polyols, further preferably polypropylene glycol (PPG) and polytetramethylene ether glycol (PTMG), and particularly preferably polytetramethylene ether glycol (PTMG).

The number of functional groups f of the polymer polyol B is preferably 1.5 to 3.5, more preferably 2 to 3, from the viewpoints of foamability during mechanical foaming, strength, elongation, and recovery of the resulting foam.

The hydroxyl value of polymer polyol B is preferably 30 to 250, and more preferably 30 to 220.

(MDI-based isocyanate)
The MDI-based isocyanate (diphenylmethane diisocyanate-based isocyanate C) is an isocyanate having a diphenylmethane diisocyanate skeleton.

Examples of MDI-based isocyanates include 4.4'-diphenylmethane diisocyanate (4.4'-MDI), diphenylmethane diisocyanates such as 2.4'-MDI and 2.2'-MDI (pure MDI), crude MDI (cr-MDI), carbodiimide-modified MDI, and polyol-modified MDI.
In particular, from the viewpoint of obtaining a fine, continuously breathable sponge, it is preferable to use an isocyanate selected from the group consisting of diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, and polyol-modified diphenylmethane diisocyanate as the MDI-based isocyanate.

Here, examples of polyol-modified isocyanates include polyol-modified isocyanates in which MDI-based isocyanates are modified with dihydric alcohols having 2 to 18 carbon atoms, such as ethylene glycol, propylene glycol, 1,3- or 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, and 1,10-decanediol; PPG-based glycols; PTGM-based glycols; polycarbonate-based glycols, etc.

Along with MDI-based isocyanates, aromatic isocyanates such as tolylene diisocyanate (TDI) used in the production of polyurethane foam, and aliphatic isocyanates such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), hydrogenated xylylene diphenylmethane diisocyanate (hydrogenated XDI), and cyclohexylene diisocyanate can also be used in combination.

(Foam stabilizer)
Examples of the foam stabilizer include well-known foam stabilizers such as silicone compounds (copolymers of polydimethylsiloxane and polyoxyalkylene polyol, etc.) and fluorine compounds. In particular, (AB)n-type silicone foam stabilizers that are commercially available as suitable for mechanical foaming can be preferably used. The foam stabilizer may be used alone or in combination of two or more kinds.

(catalyst)
Examples of the catalyst include organometallic compound catalysts and amine catalysts.
The organometallic compound catalyst includes organometallic catalysts such as tin-, titanium-, bismuth-, copper-, and nickel-based catalysts, and examples thereof include organotin compounds such as stannous octoate and dibutyltin dilaurate.
As the amine catalyst, tertiary amines are preferable, and examples of the amine catalyst include monoamines, diamines, triamines, cyclic amines, alcohol amines, and ether amines, such as triethylenediamine, triethylamine, n-methylmorpholine, n-ethylformoline, and N,N,N',N'-tetramethylbutanediamine.
The catalyst may be a temperature-sensitive catalyst in order to prevent the initiation of curing during mechanical agitation of the gas. The catalyst may be used alone or in combination of two or more kinds.

(Other ingredients)
Other components include the following additives:

Examples of other components include at least one selected from the group consisting of low molecular weight diols (ethylene glycol, 1,4-butanediol, etc.), polyfunctional low molecular weight alcohols (glycerin, trimethylolpropane, etc.), low molecular weight diols having a branched chain, polyols having an alicyclic structure, and isocyanates having an alicyclic structure.
Here, the low molecular weight diol and polyfunctional low molecular weight alcohol refer to a polyol having a molecular weight of 300 or less (preferably 60 to 300).

Other components include fillers.
The filler may be one or more selected from the group consisting of inorganic fillers and organic fillers. The addition of these fillers makes the bubbles mechanically stirred finer, and fine bubbles are less likely to be defoamed or coalesce, making it easier to obtain a fine sponge.
Examples of inorganic fillers include calcium carbonate, aluminum hydroxide, magnesium hydroxide, natural silica, synthetic silica, kaolin, clay, titanium oxide, barium sulfate, zinc carbonate, zinc oxide, glass beads, alumina beads, carbon, etc. In particular, calcium carbonate, aluminum hydroxide, and silicas are effective in forming fine cells.
Examples of the organic filler include phenol beads, styrene beads, acrylic beads, resin balloons, silicone powder, fluorine powder, nylon powder, and polyethylene powder.
Other examples of the filler include organic/inorganic fillers in which calcium carbonate is added to the surface of an acrylic balloon, and POP (polymer-dispersed polyol) in which submicron organic polymers (such as acrylonitrile or acrylonitrile/styrene copolymers) are dispersed in polypropylene polyol.

As for other ingredients, the gas used for mechanical foaming (air, nitrogen, etc.) is essential, but water (distilled water, ion-exchanged water, ultrafiltered water, pure water, etc.), low-boiling organic solvents (alkyl fluoride compounds, alkyl chloride compounds, etc.), and liquefied carbon dioxide gas can also be used in combination as foaming agents.

Other components include, in addition to the above, well-known additives such as flame retardants, antioxidants, colorants, UV absorbers, antibacterial agents, and antifungal agents.

(Content of each component in the urethane raw material liquid)
--Contents of dimer acid polyester polyol A and polymer polyol B--
The content of the dimer acid polyester polyol A is from 30% by mass to 100% by mass, and preferably from 40% by mass to 100% by mass, based on the total polymer polyol.

When polymer polyol B is used in combination, the mass ratio of dimer acid polyester polyol A to polymer polyol B (dimer acid polyester polyol A/polyol B) is preferably 30/70 to 90/10, more preferably 30/70 to 80/20, and even more preferably 40/60 to 80/20.

By controlling the content of the dimer acid polyester polyol A and the mass ratio of the dimer acid polyester polyol A to the polymer polyol B within the above ranges and performing mechanical foaming, a mechanical foam having a high foaming ratio and low hardness can be obtained, which has an appropriate liquid absorption rate and a good skin feel.
In addition, when the ratio of the polymer polyol B is increased, the foaming ratio becomes high, the density becomes low, the feel can be maintained, and it is possible to use it suitably even if the viscosity of the liquid foundation changes, but since the hydrophobicity decreases, the liquid absorption tends to increase, and the strength tends to decrease due to swelling. Therefore, from this viewpoint, it is preferable to control the mass ratio of the dimer acid polyester polyol A and the polymer polyol B within the above range.

-Foam stabilizer content-
The content of the foam stabilizer is preferably from 0.4 to 10 parts by mass, and more preferably from 3 to 5 parts by mass, based on 100 parts by mass of the high molecular weight polyol.

- Filler content -
The content of the filler (particularly, inorganic filler) is preferably 5 to 50 parts by mass, and more preferably 10 to 30 parts by mass, per 100 parts by mass of the polymer polyol, from the viewpoint of cell miniaturization.

(Characteristics of continuous ventilation sponge)
- Self-skin layer -
The continuous breathable sponge according to this embodiment may or may not have a self-skin layer. However, when it is desired to suppress the impregnation and absorption of aqueous liquids, such as in the case of a cosmetic puff for liquid foundation, it is preferable for the sponge to have a self-skin layer.

- Breathability -
Measure the thickness of the measurement sample with a digital thickness gauge. Set the sample in the Frazier type air permeability tester, adjust the pressure resistor so that the inclined air pressure gauge indicates "5", and read the pressure on the vertical air pressure gauge at that time. Use the conversion table by orifice type to find the conversion value. Calculate the air permeability using the following formula.
Formula: AP=a×t
AP: Air permeability (mL/cm ² /s)
a: conversion value t: thickness (cm)

- Apparent density -
The apparent density of the continuous breathable sponge according to this embodiment is preferably 100 to 400 kg/m3, more preferably 150 to 300 kg/ ^m3 , from the viewpoints of mechanical strength, prevention of bottoming out during compressed use, and operability, in addition to appropriate liquid ^absorbency and improved skin feel.

The apparent density is measured by the following method.
First, a sample to be measured (approximate dimensions: length 100 mm x width 100 mm x thickness measurement value) is prepared in an environment of 23±3°C. Next, the weight of the sample is measured with a precision balance to an accuracy of 1/100 g. Next, using a digital gauge, the thickness dimension of the sample is measured at nine points with an accuracy of 1/100 mm using a probe with a diameter of Φ10 mm and a load of about 0.6 N, and the average value is calculated. The length and width dimensions of the sample are measured at three points each using a digital caliper, and the average is calculated. The volume of the sample is calculated from each of the obtained dimensions. Then, the apparent density is calculated using the formula: apparent density = weight/volume.

- Tensile strength and elongation -
The tensile strength of the continuous breathable sponge according to this embodiment is preferably 0.1 MPa or more from the viewpoints of mechanical strength, prevention of bottoming out during compressed use, and operability.
The tensile elongation of the continuous breathable sponge according to this embodiment is preferably 150% or more, and more preferably 200% or more, from the viewpoints of mechanical strength and operability.

Tensile strength and elongation are measured in accordance with JIS K 6400-5 (2012). Measurements are performed by punching out the measurement object into a No. 2 dumbbell shape, obtaining a sample, and measuring the thickness. The obtained sample is then tested at a speed of 200 mm/min using Oriontec's Tensilon Universal Material Tester UCT-500. The strength and elongation at the time of sample breakage are then measured.

- Tear strength -
The tear strength of the continuous breathable sponge according to this embodiment is preferably 3 N/cm or more, more preferably 5 N/cm, from the viewpoint of mechanical strength.

Tear strength is measured in accordance with JIS 6400-5 (2012).

-50% compression hardness-
The 50% compression hardness of the continuous breathable sponge according to this embodiment is preferably 50 kPa or less, more preferably 15 kPa or less, and even more preferably 10 kPa or less, from the viewpoints of improving the feel on the skin, mechanical strength, prevention of bottoming out when compressed, and operability.
The 50% compression hardness is measured in accordance with JIS K6400-2 (2012).
Specifically, a sample with a size of 50 x 50 mm is punched out from the measurement target. If the thickness is 10 mm or less, the sample is laminated to a thickness of 10 mm or more. Then, using a "Tensilon Universal Material Tester UCT-500" manufactured by Oriontec Co., Ltd., the sample is compressed by 50% of the sample thickness at a compression speed of 50 mm/min, and the 50% compression hardness is measured.

-Water absorption rate-
The water absorption rate of the continuous breathable sponge according to this embodiment is preferably 20% by mass or less, more preferably 15% by mass or less, and most preferably 12% by mass or less, from the viewpoint of appropriate liquid absorption.
The water absorption is measured as follows.
Prepare a 10 cm square sample and measure its mass to the nearest 1/100 g. Next, pour 10 cm of water into a water tank, submerge the sample to a depth of 10 cm, and leave it for 24 hours. After 24 hours, wipe off the water on the sample surface and measure the mass of the sample to the nearest 1/100 g. Then, measure the liquid absorption rate using the following formula.
Water absorption rate (%) = (mass after water absorption - mass before liquid absorption) / mass before water absorption x 100

-Average cell diameter-
The average cell diameter of the continuous breathable sponge according to this embodiment is preferably 270 μm or less, more preferably 250 μm or less, and even more preferably 200 μm or less, from the viewpoint of mechanical strength in addition to suitable liquid absorbency and improved skin feel.

The average cell diameter is calculated by measuring the number of cells per 25 mm length in accordance with JIS K 6400-1 (2004) Appendix 1 and calculating it from 25 mm/number of cells. Note that the average cell diameter is measured under magnification using an optical microscope.

(Manufacturing method of continuous ventilation type sponge)
The method for producing the continuous breathable sponge according to the present embodiment is not particularly limited. For example, the method for producing the continuous breathable sponge according to the present embodiment may be the following method.
A method for producing a continuous breathable sponge, comprising: a coating step in which a urethane raw material liquid is mechanically foamed using an oak mixer or the like, and the foamed urethane raw material liquid is continuously applied onto a first continuous web (strip) to form a coating film; and a heating step in which the coating film on the first continuous web is heated and hardened to form a foam having a continuous breathable structure.

On the other hand, there are many advantages to a process that includes a second continuous web supplying step of supplying a second continuous web (strip) to the coating film on the first continuous web (strip) after the coating step and before the heating step, thereby sandwiching the coating film between the two continuous webs, and a heating step of heating and hardening the coating film while it is sandwiched between the two continuous webs.
In particular, when a coating of a urethane raw material liquid is heated and cured while sandwiched between two continuous releasable webs to form a foam with a continuous air permeability structure, the foam is formed while sandwiched between the two continuous webs, and there is no scattering of the foaming agent, leading to a high expansion ratio (low density). Another major feature is that a thin, smooth skin layer is formed on both surfaces, which fits well with the fingers (feels moist to the touch), and it is easy to obtain a foam with a continuous air permeability structure (i.e. a sponge) with a high texture.

The manufacturing method for this type of continuous ventilation sponge will be explained below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of an apparatus configuration for carrying out the method for producing a continuous-ventilation sponge according to this embodiment.
As shown in FIG. 1, the continuous breathable sponge manufacturing apparatus 100 includes a first web roll 14 that delivers a first continuous web 14A, a coating device 12 that coats the first continuous web 14A with a urethane raw material liquid, a large-diameter roller 18 that guides the first continuous web 14A delivered from the first web roll 14 to directly below the coating device 12, a second web roll 16 that delivers a second continuous web 16A, a guide roller 20 that guides the second continuous web 16A onto the coating film 10 on the first continuous web 14A, transport rollers 28A, 28B that guide the coating film 10 of the urethane raw material liquid sandwiched between the two continuous webs 14A, 16A to a heating device 22 and transport a foam (hereinafter referred to as a "urethane foam sheet") 30 that has been heated and hardened by the heating device 22, and recovery rollers 24, 26 that roll up and recover each of the continuous webs 14A, 16A peeled off from the urethane foam sheet 30.

-Coating process-
First, a urethane raw material liquid obtained by mixing and stirring raw material components is continuously coated onto the first continuous web 14A to form the coating film 10.

The first continuous web 14 is preferably made of, for example, a resin film or a paper body.
The resin film is not particularly limited as long as it does not deform when heated during the application and heating steps of the urethane raw material liquid. From the standpoint of resistance to the urethane raw material liquid, heat resistance, etc., films of polyester, polypropylene, polymethylpentene, etc. are preferred.
If necessary, the surface of the resin film may be subjected to a corona discharge treatment, a plasma treatment, or the like to improve adhesion to the urethane foam sheet.

In addition, a resin film may be used in which the surface on which the coating film of the urethane raw material liquid is formed has releasability so that the resin film can be easily peeled off after the urethane foam sheet is produced.
Methods for producing a resin film having releasability include coating one side of the resin film with a silicone release agent, using a resin film having releasability such as polypropylene resin or polymethylpentene resin as is, and laminating a resin film having releasability onto a polyester film, etc. In addition, the surface of the release film or paper-based release paper can be given a matte finish or a grain pattern to enhance the design and texture.

When a paper body is used as the first continuous web 14A, the surface of glassine paper or fine paper is coated with polypropylene, or a silicone release agent or a non-silicone release agent is further applied on top of the polypropylene.
The first continuous web 14A used in the present invention is preferably a resin film or a release resin film, since the foam solidifies quickly and has high thickness accuracy.

As the coating device 12 for coating the urethane raw material liquid on the first continuous web 14A, it is preferable to use a die coater, roll coater, knife coater, comma coater, etc. A method in which the urethane raw material liquid is stirred with a mixing device and discharged from a discharge nozzle with a traverse (repeated coating) device and thinly coated with a roll coater or knife coater, or a method in which the urethane raw material liquid is introduced from a discharge nozzle into a die coater and coated on the continuous web, are also preferable.

The thickness of the coating film 10 can be determined according to the intended use of the foam (continuously air-permeable sponge).

-Second continuous web supplying step-
A second continuous web 16A is fed onto the coating film 10 on the first continuous web 14A, and the coating film 10 is sandwiched between the two continuous webs 14A, 16A.
The second continuous web 16A can be a resin film or a paper body as exemplified in the description of the first continuous web 14A. From the viewpoint of facilitating peeling of the continuous web on at least one side of the urethane foam sheet 30 after the heating step, it is preferable that at least one of the first continuous web 14A and the second continuous web 16A is a continuous web whose surface in contact with the coating film 10 has releasability.

The second continuous web 16A is continuously unwound from the second web roll 16 on which it is wound, and is placed over the coating film 10 on the first continuous web 14A. This results in the coating film 10 being sandwiched between the two continuous webs 14A and 16A.

The device shown in FIG. 1 is configured to sandwich the coating film 10 between two continuous webs 14A and 16A, but after forming the coating film on the first continuous web 14A, it is also possible to proceed to the next heating step without covering it with the second continuous web 16A.

-Heating process-
The coating film 10 is sandwiched between two continuous webs 14A, 16A and conveyed into a heating device 22 where it is cured by heating.
The heating temperature for curing is preferably 80 to 120° C., and curing is preferably accomplished within this temperature range for 5 to 20 minutes.
The heating device 22 may be an infrared heater, an electric heater, a gas combustion furnace, or the like.

- Peeling process -
The urethane foam sheet 30 that has been foamed and cured by the heating step may be wound up with the continuous webs 14A, 16A in close contact with the urethane foam sheet 30, or, if the continuous webs 14A, 16A are release webs, the release webs are peeled off from the urethane foam sheet 30 and wound and recovered on each of the recovery rollers 24, 26 as shown in Figure 1. The recovered continuous webs 14A, 16A can be reused as supply rolls 14, 16.

Through the above process, a continuous ventilation type sponge made of a urethane foam sheet (a foam with a continuous ventilation structure) can be continuously produced.

When the continuous breathable sponge according to this embodiment has low breathability, it may be subjected to a crushing process (a process in which the foam is compressed by shearing to increase breathability) if necessary. If it is used with low breathability, the recovery speed will be slow, and if the breathability is increased, the recovery will be quicker, so the breathability can be adjusted according to the application.

In addition to the above, known methods such as the slabstock method and the molding method in which the sponge is molded in a mold can be used to manufacture the continuous ventilation sponge according to this embodiment.

In this specification, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

(Applications of continuous ventilation sponge)
The continuous breathable sponge according to this embodiment can be used for applications such as cosmetic puffs, brassiere pads, sports clothing pads, body protection pads (head, knee or elbow pads, etc.), medical pads (for corns, etc.), insoles, supports, waterproof sealing materials, liquid (medicine, lotion, etc.)-impregnated sheets, masks, and bandages.

(Cosmetic puff)
The cosmetic puff according to the present embodiment has the continuous ventilation type sponge according to the present embodiment. This prevents the cosmetic puff according to the present embodiment from being excessively soaked with liquid foundation. This reduces the consumption of liquid foundation. In addition, the liquid foundation is comfortable to wear.

The cosmetic puff according to this embodiment may be a puff with a single layer structure of the continuously breathable sponge according to this embodiment, or a puff with a multi-layer structure in which the continuously breathable sponge according to this embodiment is integrated with another skin material.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following, "parts" are by weight unless otherwise specified.

Example 1
High molecular weight polyol A (polyester polyol obtained from dimer acid and diethylene glycol, manufactured by Hitachi Chemical Co., Ltd., OHv = 85, viscosity 5500 mPa s) 100 parts Foam stabilizer SZ1923 (silicone-based foam stabilizer manufactured by Toray Dow Co., Ltd.) 5 parts,
Catalyst SO (Mitsubishi Chemical, Stannous Octate) 0.1 parts The mixture containing the above polyol components other than isocyanate is continuously fed to the Oaks Mixer, and nitrogen gas is fed to mechanically foam the mixture. 22.4 parts of isocyanate (Tosoh, carbodiimide-modified diphenylmethane diisocyanate (carbodiimide-modified MDI), NCO% = 29) are added to the Oaks Mixer, and the polyol components and isocyanate are reacted and discharged. The total discharge rate of the raw material is 250g/min, and the discharge rate of nitrogen gas is 800cc/min. The discharged reaction liquid is applied to a release film, cured at 70°C for 5 minutes, then at 100°C for 10 minutes, to obtain a continuous breathable sponge with a thickness of about 8mm.

<Examples 2 to 15 and Comparative Examples 1 to 7>
A continuous-ventilation sponge was obtained in the same manner as in Example 1, except that the types and amounts of materials (the numbers in the tables are the number of parts) were changed according to the compositions in Tables 1 to 8.
However, in Examples 13 and 14, a block-shaped sponge of 50 mm thick, 200 mm long, and 200 mm wide was produced under the same mechanical foaming conditions as in Example 1, and then sliced to a thickness of 8 mm to obtain a continuous-breathable sponge without an own skin layer.
In addition, in Comparative Examples 4 to 6 (water foaming), a continuous ventilation type sponge was obtained as follows. The stirred urethane raw material liquid was applied to a release-treated release film using a die coater so that the thickness after curing was about 8.0 mm, and another release film was placed on top of the coating film so that the release-treated surface was in contact with the coating film of the urethane raw material liquid. Next, the coating film of the urethane raw material liquid was heated and cured in an oven at temperatures of 80°C x 3 minutes and 100°C x 5 minutes while sandwiched between two release films. After that, the films on both sides were peeled off to obtain a continuous ventilation type sponge with a thickness of about 8.0 mm.
In Comparative Examples 7 and 8, commercially available products were used.

<Physical property measurements>
The following physical properties of the continuous breathable sponge obtained in each example were measured according to the methods described above.
Apparent density, tensile strength, tensile elongation, tear strength, 50% compression hardness, water absorption rate, average cell diameter, air permeability

<Evaluation>
The continuous ventilation type sponge obtained in each example was subjected to the following evaluations.
-Skin feel-
Regarding the feel on the skin, five women checked the feel on the skin when applying makeup, and monitored and evaluated it according to the following criteria. The most common evaluation among the five people is shown in the table.
◎: Very good skin feel ◯: Good skin feel △: Slightly rough or stiff feeling, not good skin feel ×: Poor skin feel

-Feel index-
The feel index was quantified by multiplying the 50% compression hardness and the cell diameter. The multiplied value was correlated with the above-mentioned skin feel monitoring evaluation, with a value lower than 2 indicating very good feel, a value between 2 and 3 indicating good feel, a value between 3 and 4 indicating a slightly rough or stiff feel and a value above 4 indicating a poor feel.

-comprehensive evaluation-
The continuous ventilation type sponge of each example was comprehensively evaluated according to the following criteria.
◎: Puff sponge with very good skin feel and low water absorption. 〇: Puff sponge with good skin feel and low water absorption. △: Puff sponge with not so good skin feel and high water absorption. ×: Puff sponge with poor skin feel and high liquid absorption.

From the above results, it is evident that the continuous ventilation type sponge of the Example has an appropriate liquid absorption rate and a good feel on the skin compared to the sponge of the Comparative Example.
Here, the degree of penetration of liquid foundation into the continuous air-permeable sponge of Example 4 and the sponge of Comparative Example 7 are shown in Figs.
As shown in FIG. 2, the continuous ventilation type sponge of Example 4 is appropriately soaked with liquid foundation, whereas as shown in FIG. 3, the sponge of Comparative Example 7 is excessively soaked with liquid foundation.

The details of the components shown in the table are as follows.
-High molecular weight polyol A-
Dimer acid polyester polyol A1: Dimer acid polyester polyol obtained from dimer acid and diethylene glycol, manufactured by Hitachi Chemical Co., Ltd., hydroxyl value OHv = 85 mg KOH/g, viscosity (25°C) = 5500 mPa·s
Dimer acid polyester polyol A2: Dimer acid polyester polyol obtained from dimer acid and diethylene glycol, manufactured by Hitachi Chemical Co., Ltd., hydroxyl value OHv = 150 mg KOH/g, viscosity (25°C) = 2000 mPa·s
Dimer acid polyester polyol A3: Dimer acid polyester polyol obtained from dimer acid and diethylene glycol, manufactured by Hitachi Chemical Co., Ltd., hydroxyl value OHv = 70 mg KOH/g, viscosity (25°C) = 10,000 mPa·s

-Polyol B-
PTMG: Polytetramethylene ether glycol, hydroxyl value OHv = 133 mg KOH/g, number of functional groups f = 2
PCL: Polycaprolactone diol, hydroxyl value OHv = 210.8 mg KOH/g, number of functional groups f = 2
Adipate: Adipic acid ester polyol (polyol obtained by condensing adipic acid and 1,3-butanediol, hydroxyl value OHv = 117 mg KOH/g, number of functional groups f = 2
PPG: polypropylene glycol, hydroxyl value OHv = 112 mg KOH/g, number of functional groups f = 2, molar ratio of ethylene oxide EO = 0%, 30%

-Filler-
・CaCO3: Sankyo Seifun Co., Ltd., general-purpose calcium carbonate, grade 1 ・Al(OH)3: Aluminum hydroxide: Showa Denko Co., Ltd., Hijilite H10

-Foam stabilizer-
SZ1923: SZ-1923, manufactured by Toray Dow, silicone foam stabilizer

-catalyst-
Stannous octate: Metal catalyst, SO (Mitsubishi Chemical Corporation, Stannous octate)
Dabco 33Lv: Amine catalyst, Dabco 33Lv (manufactured by Air Products Japan Co., Ltd.)

-Isocyanate-
Carbodiimide-modified MDI: Tosoh Corporation, carbodiimide-modified diphenylmethane diisocyanate, NCO%=29

- Commercially available -
・Commercially available NBR-based puff: NBR sponge manufactured by Yukiya Chemical Co., Ltd. ・Commercially available pore agent extraction method PU-based puff: Ruby Cell manufactured by Toyo Kagaku Co., Ltd.

Reference Signs List 10 Coating film 12 Coating device 14 First web roll 14A First continuous web 16 Second web roll 16A Second continuous web 18 Large diameter roller 22 Heating device 24 First recovery roll 26 Second recovery roll 30 Foam with continuous ventilation structure (urethane foam sheet)
100 Continuous ventilation sponge manufacturing equipment

Claims (1)

a polymer polyol having a hydroxyl value (OHv) of 250 mgKOH/g or less, the polymer polyol containing 30% by mass or more and 100% by mass or less of a dimer acid polyester polyol based on the total polymer polyol;
Diphenylmethane diisocyanate-based isocyanates,
A foam stabilizer,
A catalyst;
A cosmetic puff having a continuous air-permeable sponge composed of a mechanical foam of a composition comprising: