JPS5976247A - Multilayer structure porous elastic body and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multilayered porous elastic body used as a cosmetic puff or the like and a method for producing the same. .

Powder-type cosmetics used during hot and humid times such as summer are called water-based cosmetics, and are made by hardening cosmetic powder into a cake shape, which is melted and applied to the skin using a sponge-like puff impregnated with water. It is something that will be done. The sponge-like puff used to apply this aqueous cosmetic is made of a natural 2-synthetic porous elastic material made of sponge, polyurethane, rubber latex, polyolefin, and polyvinyl acetal. Since sponges, which are natural products, can only be produced and harvested in limited locations, synthetic porous elastic materials have recently been used. There are two types of synthetic poroelastic materials: hydrophilic and hydrophobic, and the former includes polyvinyl acetal (
A porous elastic body (hereinafter abbreviated as "rPVAt type") is used as the base, and a polyurethane type or rubber latex type porous elastic body is used as the support for the latter. The PVAt-based porous exoporoelastic material has a large number of hydroxyl groups in its molecular structure, making it highly hydrophilic and easy to absorb moisture, and this moisture penetrates inside and produces a plasticizing effect, resulting in flexibility. 1 elasticity. On the other hand, most polyurethane-based and rubber latex-based porous elastic materials have hydroxyl groups in their molecular structures.
Its elasticity is due to its porous shape.
Demonstrates strong elasticity regardless of moisture. Water-based cosmetics are
Since it is used after being dissolved in water, hydrophilic PVAt-based puff materials are preferred over hydrophobic polyurethane-based and rubber latex-based puff materials. In other words, hydrophilic PVAt-based materials are slightly inferior in elasticity to hydrophobic materials, but they "fit" cosmetics better and are superior in terms of feel on the skin and imparting a cooling sensation, so they are suitable for puff materials for water-based cosmetics. It is widely used as However, when this PVAt-based porous extraporous elastic material is dried, the water content is 50% (overlapping, the same applies hereinafter).
If the temperature drops below that level, the molecular structure lacks water that acts as a plasticizer, and the hydroxyl groups between two molecules in the molecule form strong hydrogen bonds, making it extremely hard, resulting in the loss of its properties as a para. be.

In order to simulate a long period of time for softening once hardened, puffs are actually stored and carried in a moisturizing container specifically designed for puffs. However, in this case, the makeup tools are bulky and the 3ffi
Since t also increases, its improvement is strongly desired.

Therefore, an attempt was made to bring out only the advantages of both by laminating a hydrophilic porous elastic material such as PVAt-based material on top of a hydrophobic porous elastic material such as polyurethane material1. However, this composite porous elastic material is simply a layered material with completely different properties, and no consideration was given to the dimensional difference between the softening and drying states of the PVAt-based hydrophilic poroelastic material. As a result, it had the disadvantage of becoming distorted when drying, making it a worthless item sold illegally.

In other words, since the PVAt-based hydrophilic poroelastic material contracts about 10 degrees during the transition from a softened state to a dry state, a composite poroelastic material in which it is laminated on a hydrophobic poroelastic material has no strain. occurs.

In addition, consideration has been given to quickly changing the PVAt-based hydrophilic poroelastic material from a dry and hardened state to a softened state.
Since it takes a considerable amount of time to change from a dry, hardened state to a softened state, improvements in carrying and storing the product in a moisturizing container have not been achieved. In particular, if a composite porous elastic body using a polyurethane-based hydrophobic porous elastic body is placed in such a moisturizing container, the polyurethane-based porous elastic body will hydrolyze and become brittle. This was a major hindrance to development.

As a result of a series of studies conducted by the present inventors to solve these problems, we found that the time required for a PVAt-based porous elastic material to soften due to water content depends on its degree of acetalization and pore size. It has been found that the thickness of the elastic body has the greatest influence, although it is influenced to some extent by the elasticity, pore diameter, etc.

That is, the average degree of 1 degree is 1700. PVAt with an average pore diameter of 130μ made from fully saponified polyvinyl alcohol
Using a porous external porous elastic material (tarring degree 55%), dry state is 0.2 yen, 0.5 yen, 2. Own
, 3.0wn p 5. OrMn+ 10.0rI
As a result of making a sheet with a thickness of n and measuring the time it takes to soften by immersing it in water, the following results were obtained: 1. Oran
The following thicknesses soften within 10 seconds, 3.0mm thick takes about 40 seconds, and 10.0mm thick takes about 30 seconds to soften.
It took 60 seconds. This was almost the same when PVAt-based porous elastic bodies having different degrees of acetalization and different porosities were used. From this result, it was inferred that the thickness of the PVAt-based porous elastic body needs to be set thin in order to be able to be used as a puff for aqueous cosmetics without any practical complication. Therefore, the Ministry of the Invention and others conducted further research and developed a thin layer of such a PVAt-based poroelastic material using a polyurethane-based material, which has a superior degree of elasticity compared to the l'VAt-based poroelastic material. When formed on a hydrophobic poroelastic material, the elasticity of the hydrophobic poroelastic material is transmitted to the thin layer of the PVAt-based poroelastic material, and the PV
The quality of the At-based porous extra-porous elastic body itself is improved, and the PV
Since the At-based porous elastic material is a thin layer, the force caused by the dimensional difference between softening and drying is small and no distortion occurs. We discovered that softening can be achieved in a short time by moistening it with water, eliminating the need to carry or store it in a moisturizing container as in the past, and arrived at this invention.

That is, the present invention provides a multilayer structure poroelastic material in which the surface of a substrate made of a porous elastic material is completely or partially broken with a thin layer made of a polyvinyl acetal poroelastic material different from the substrate. A part or all of the surface of a porous elastic body is thinly coated with an aqueous polyvinyl alcohol solution containing an aldehyde crosslinking agent, a mineral acid catalyst, and a powdered pore forming agent. The acetalization of polyvinyl alcohol was carried out at a relative humidity of 8.
5% or more 2. Reaction temperature: 30-50°C 1. Reaction time: 1-5 hours to form a polyvinyl acetal thin layer, dissolve and remove the powdered pore-forming agent in this polyvinyl acetal thin layer, and leave traces of removal. The second gist is to obtain a porous elastic body with a multilayer structure by forming pores.

Next, the present invention will be explained in detail.

First, the structure of the multilayer porous elastic body of the present invention will be explained.

FIG. 1 is a cross-sectional view of an example of a multilayer porous elastic material of the present invention, in which the can is broken with a base 1 made of a polyurethane poroelastic material and a thin layer 2 made of a PVAt poroelastic material. A porous elastic body is constructed.

In this multilayered porous elastic material, layer 2 made of a PVAt porous elastic material is thin, so distortion does not occur due to the dimensional difference between softening and drying, and it can be softened from a dry state. It takes a short time and is easy to use. Since the thin layer 2 is made of a PVAt-based porous elastic material,
Aqueous cosmetics can be applied easily and provide an excellent feel and cool feeling. Further, even if the thin layer 2 of IPIJ is dried and hardened, the elasticity of the base 1 is transmitted to the thin layer 2, so that the hardness of the thin layer 2 is hardly felt by the skin. Therefore, the thin layer 2 can be used even after drying and hardening, and can also be used as a puff for dry cosmetics other than water-based cosmetics.

FIG. 2 is a perspective view of a modification of FIG. 1. That is, this multilayer structure porous elastic body is made by covering the entire base 1 made of a polyurethane porous elastic body with a thin layer 2 of a PVAt porous elastic body, punching this with a die, and then bending the side surfaces. It exhibits the same effect as the one shown in Fig. 1.

FIGS. 3 and 4 are also explanatory diagrams of modifications of FIG. 1.

In other words, this multilayer structure porous elastic body.

On the surface of the base 1 made of polyurethane thread porous elastic material,
It is constructed by forming a thin layer 2 made of a PVAt-based poroelastic material into a discontinuous layer divided into a large number of independent regions, and then punching it out with a die.

When the thin layer 2 is formed as a discontinuous layer in this way, PVAt
It becomes possible to almost eliminate distortion due to the dimensional difference between the softening and drying of the porous elastic body.

In particular, when doing this, the thickness of the base 1 is thin and PVAt
This method is effective when it is impossible to absorb distortion due to the dimensional difference between the dry state and the softened state of the porous elastic material. Such an effect can also be obtained by forming the continuous thin layer 2 shown in FIGS. 1 and 2 into an aggregate of fine particles.

The thickness of the thin layer 2 of the PVAt-based porous poroelastic material is determined by the time required for softening and the elasticity of the substrate 1 to be transferred to the thin layer 2, thereby preventing the occurrence of distortion. It is preferable to set the distance to 3.0 mm or less.

At the same time, the method for manufacturing the multilayer porous elastic body of the present invention will be explained.

That is, first, a stock solution of a PVAt-based porous elastomer is applied to a predetermined thickness on the surface of a substrate made of a hydrophobic poroelastic material such as polyurethane-based or rubber latex-based material. This PVAt-based porous extraporous elastic material stock solution has an average polymerization degree of 30
0 to 3000, a degree of saponification of 80 degrees or higher, and a mixture of one or more polyvinyl alcohols in which some of the hydroxyl groups have been substituted with other functional groups as necessary, and dissolved in water to obtain a
Aldehydes are used as a crosslinking agent in an aqueous solution with a concentration of around 10%.

It is constructed by adding and mixing mineral acids as a catalyst and ground powder having an appropriate particle size as a pore-forming agent. The reaction stock solution is usually applied by spraying the reaction stock solution onto the surface of the substrate in the form of a mist using a fine nozzle. This method is easier than methods using paulownia hair, rollers, dipping, etc., and has the advantage that it is easy to form a thin coating layer, and it is also easy to make the coating layer discontinuous. . The reaction stock solution may be applied by transferring the reaction stock solution onto the surface of the substrate in a pattern using an engraved roller, a screen mold, a paper pattern, or the like having a pattern engraved on its outer peripheral surface. In this case, by changing the color tone of the reaction stock solution and the base material, the pattern can be made to stand out.

At the same time, the reaction stock solution applied to the surface of the substrate is reacted to form a thin layer of PVAt-based porous elastic material on the surface of the substrate. In this case, the reaction conditions for the reaction stock solution are as follows: a commercially available product (block-shaped P
Conditions different from those used for producing VAt-based poroelastic body), i.e., reaction temperature 30 to 55°C, reaction time 1
The relative humidity is set to 85 degrees or higher for ~5 hours. Commercially available products are manufactured by pouring the reaction stock solution into a mold and reacting at a temperature of about 60°C for 15 to 30 hours. When forming a thin layer, if carried out under these conditions, the reaction will proceed too quickly, resulting in side reactions or decomposition reactions, or a product with no elasticity. A phenomenon occurs. The present invention, in order to prevent the occurrence of such problems,
By changing the reaction temperature and time as above while keeping the composition of the reaction stock solution the same, and by keeping the reaction atmosphere at high humidity to suppress the evaporation of water from the thin layer (the increase in acid concentration is suppressed). , PVAt that suppresses the progress of the reaction and is attractive
In this way, a thin layer of porous elastic material is formed. That is, a PVAt-based porous elastic thin layer having good elasticity can only be formed by reacting the reaction stock solution under the above-mentioned conditions, and setting these reaction conditions is extremely costly.

For example, if the reaction temperature or reaction time is below the above range, the reaction will not proceed sufficiently and unreacted polyvinyl alcohol will remain; if it exceeds the above range, the crosslinking reaction will proceed too much and a thin PVAt layer will be formed. elasticity and hydrophilicity are impaired. Furthermore, if the relative humidity of the reaction atmosphere is less than 85%, the evaporation of water from the thin layer becomes intense and the reaction system is disturbed, making it impossible to obtain normal pore size and porosity, and the crosslinking reaction progresses excessively. In severe cases, acid burning may occur, and thin layers may peel off.

Next, the PVAt on the surface of the substrate formed in this way is
The thin elastic layer is cleaned using water or the like. Through this treatment, excess aldehydes and mineral acids are removed, and starches in the PVAt elastic thin layer are sequentially dissolved and removed from the surface side of the thin layer, leaving continuous pores behind. As a result, P
The VAt elastic material becomes a thin layer or porous.

In this way, a multilayered porous elastic body is obtained in which all or part of the surface of the substrate made of a hydrophobic porous elastic body is coated with a thin layer of a PVAt porous elastic body. This multilayer structure porous elastic material has a base surface covered with a thin layer of hydrophilic P″VAt porous elastic material, so water-based cosmetics can be easily applied to it, and it is excellent in terms of feel on the skin and providing a cool feeling. The thin layer of the PVAt-based porous elastic material is reinforced by the elasticity of the base made of the hydrophobic porous elastic material, giving it a good feeling of use. Due to the thin layer of elastic material, it quickly changes from a dry, hardened state to a softened state.Therefore, there is no need to carry or store it in a moisturizing container as in the past.In addition, PVA
Since the t-based porous elastic layer is thin, the force generated due to the dimensional difference between dry hardening and softening is small. Therefore, distortion does not occur during drying and commercial value is not impaired. In other words, this multilayered porous elastic material is an excellent product that combines the advantages of a hydrophobic porous elastic material and the advantages of an l'VAt yarn porous elastic material, and is suitable for use as a puff for water-based cosmetics. It is the most suitable material. In particular, the multilayered porous elastic body produced by the method of the present invention has a PVAt-based porous extra-porous elastic body formed directly on a hydrophobic porous elastic body, and both layers are coated with an adhesive or the like. Since they are not in contact with each other, the elasticity of the elastic body will not be impaired by the highly hard adhesive layer.

Next, implementation 0 will be explained.

[Examples 1 to 9. Comparative Examples 1 to 11) Potato starch as a pore-forming agent was added to a 10% water F6 solution of polyvinyl alcohol (degree of polymerization 17'OO, 1% total saponification) at 6≦ and heated to 60°C, Then, excess formaldehyde and sulfuric acid were added to prepare a reaction stock solution. This reaction stock solution was applied to the surface of a rubber latex porous elastic sheet (8 mm thick) to form a coating layer 2 mm thick. Next, this was placed in a reaction tank and acetalized under the conditions shown in Table 1 to obtain a multilayered porous elastic body. The condition of the PVAt layer was as shown in Table 1. In the table, those with circled numbers are Examples, and the others are Comparative Examples. In addition, when the reaction of each Example was carried out in a dryer without humidity control, excessive curing, delamination between two layers, and acid burn were observed in all cases, although there were differences in degree.

(Margins below) [Examples 10 to 15] After applying the same reaction stock solution as used in Example 1 to the surface of a polyurethane porous elastic sheet (8 m thick) in varying thicknesses, Place it in a reaction tank and keep the relative humidity at 85%.
11. Acetalization was carried out by setting the reaction temperature at 45° C. and the reaction time appropriately between 1 and 5 hours depending on the thickness of the coating layer. PVA with a thickness as shown in Table 2
A multilayered porous elastic body having a thin t-type porous elastic body was obtained. The performance of this elastic body as a puff is shown in Table 2.

[Examples 16 to 18] A reaction stock solution similar to that used in Example 1 was prepared, and this was sprayed onto the surface of a slightly thin polyurethane porous elastic sheet having a thickness of 3III11 using a sprayer. Form a coating layer with a relative humidity of 8 in the reaction tank.
5% or more 9 Reaction temperature 40°C.

Table 3 shows the performance of the elastomer, which was acetalized under conditions of a reaction time of 2 hours to obtain a multilayered porous elastomer, as a puff. Although this product is composed of a base material or a thin elastic sheet, no deformation occurred due to dimensional changes in the PVAt-based porous elastic material.

[Example 19] A powder-type eyeshadow applicator was made by wrapping the multilayer porous elastic sheet obtained in Example 17 around the tip of a thin plastic rod to completely cover the tip. . This product can be used with or without water;
The usability was better than the conventional 811-0 product.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of an example of the present invention, FIGS. 2 and 3 are perspective views of modifications thereof, and FIG. 4 is a partial sectional view of FIG. 3. 1...Substrate 2...PVAt-based porous extraporous elastic thin layer Patent applicant Nakamura Bussan Co., Ltd. Agent Patent attorney Yukihiko Nishifuji 221

Claims (6)

[Claims] (1) A multilayer structure porous elastic body in which the surface of a base body made of a porous elastic body is wholly or partially covered with a thin layer made of a polyvinyl acetal porous elastic body different from the base body. (2) The multilayer porous elastic body according to claim 1, wherein the thin layer of the polyvinyl acetal porous elastic body is a discontinuous layer divided into a large number of independent regions. (3) The multilayered porous elastic body according to claim 1 or 2, wherein the porous elastic body constituting the base body is a hydrophobic porous elastic body. (4) Part or all of the surface of a porous elastic body is thinly coated with an aqueous polyvinyl alcohol solution containing an aldehyde crosslinking agent, a mineral acid catalyst, and a powdered pore forming agent, and in this state, the acetal of polyvinyl alcohol is coated. 1. Relative humidity 85% or more. A thin layer of polyvinyl acetal is formed by performing the reaction at a reaction temperature of 30 to 50° C. and a reaction time of 1 to 5 hours, and the powdered pore-forming agent in this thin layer of polyvinyl acetal is dissolved and removed to form pores in the residue left after removal. The method is characterized in that a multilayer structure porous elastic body is obtained in which the surface of the base body made of a porous elastic body is entirely or partially covered with a thin layer made of a polyvinyl acetal porous elastic body that is different from the base body. A method for producing a multilayered porous elastic body. (5) A method for producing a multilayered porous elastic body according to claim 4, in which a part or the entire surface of the substrate is coated with an aqueous polyvinyl alcohol solution by spraying a polyvinyl alcohol bath liquid under pressure from a fine nozzle. . (6) The method for producing a multilayered porous elastic body according to claim 4, wherein part or all of the surface of the substrate is coated with an aqueous polyvinyl alcohol solution by transfer using an engraving roller, a screen mold, or a paper pattern.