JP2004323816A - Production method for foamed body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method for a foamed body having a uniform foamed structure, good in touch feeling and water retainability and excellent in outer appearance, from low-viscosity viscous materials of a hydrophilic natural polypeptide and/or a hydrophilic natural polysaccharide. <P>SOLUTION: After the aqueous solution or suspension of the hydrophilic natural polypeptide and/or natural polysaccharide is converted to a sherbet-like state by cooling under stirring, the sherbet-like product is filled into a block-shaped mold, followed by being compression-molded, and after the molded product is frozen in a freezer at ≤-20°C, the block-shaped frozen product is taken out from the mold and then is subjected to vacuum drying. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a foam, and more particularly to a method for producing a foam having excellent feel and water retention.
[0002]
[Prior art]
In recent years, packing with a hydrophilic sheet containing cosmetics for the purpose of moisturizing the skin and improving rough skin has been actively performed in recent years. In addition, in order to recover the skin that has been damaged by tanning outdoors after the skin has been depilated by an esthetic treatment or the like, a lotion having an anti-inflammatory effect is included in a hydrophilic sheet and packed.
[0003]
As the sheet to be impregnated with the lotion, a sheet obtained by processing pulp into a sheet or a nonwoven fabric of cellulose is generally used, and a sponge-like sheet obtained by foaming bovine-derived collagen by a freeze-drying method with an emphasis on feel is used. Is known.
A sheet containing pulp or cellulose as a main component is inexpensive, but is inferior in commerciality due to a rough feel. On the other hand, materials made from mammals also tend to be inferior in marketability, as is the case with mad cow disease.
[0004]
Therefore, in recent years, natural polypeptides such as marine collagen extracted from fish skins and scales and natural polysaccharides such as chitosan, which has high affinity for skin, have been used as alternatives to collagen derived from mammals such as cows and pigs. A foam sheet for skin care as a main component has been studied.
[0005]
In order to obtain a foam by the freeze-drying method described above, generally, a viscous material obtained by dissolving or suspending a material in water is rapidly frozen by immersing it in a shock freezer or an antifreeze solution such as alcohol cooled below freezing. Thereafter, vacuum drying is performed to obtain a foam in which the ice crystal portion at the time of freezing is bubbles.
[0006]
[Problems to be solved by the invention]
However, in the above-mentioned vacuum drying method, there is a difference between the time when the water near the surface and the water at the center become ice, the ice crystals formed near the surface grow, and the water near the center freezes with little water. Is performed. Subsequent drying of such frozen material under vacuum to sublime the ice crystals results in the formation of non-uniform, large bubbles which result in a foam having an undesirable appearance. In particular, marine collagen and chitosan are structurally more fragile than mammalian-derived collagen, so the viscosity of the viscous material is low, so that ice crystals grow remarkably during freezing and have a uniform cell structure after vacuum drying. It is difficult to obtain a foam having the same.
[0007]
Therefore, an object of the present invention is to use a hydrophilic natural polypeptide having a low viscosity such as marine collagen or chitosan, and / or a viscous material of a hydrophilic natural polysaccharide, and have uniform air bubbles and appearance. It is an object of the present invention to provide a method for producing a foam which can satisfy the above requirements and is excellent in feel and water retention.
[0008]
[Means for solving the problem]
The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a viscous product of a hydrophilic natural polypeptide or / and a hydrophilic natural polysaccharide having a low viscosity such as marine collagen or chitosan. It was found that fine ice crystals could be obtained by cooling to below the freezing point with stirring, and this was freeze-treated and frozen, followed by vacuum drying to obtain a foam having a uniform cell structure.
[0009]
Specifically, an aqueous solution or suspension of a hydrophilic natural polypeptide such as collagen or chitosan or / and a hydrophilic natural polysaccharide is cooled while stirring to form a sherbet, and then filled into a mold. After compression-molding, and then freezing in a freezer at -20 ° C or lower, it was found that a foam having a uniform cell structure was obtained by vacuum-drying the block-like frozen material removed from the mold.
[0010]
The present invention has been made on the basis of these findings, and it is possible to cool an aqueous solution or suspension of a hydrophilic natural polypeptide such as marine collagen or chitosan and / or a hydrophilic natural polysaccharide while stirring. After forming into a sherbet shape, filling in a mold, molding, freezing, and vacuum drying.
[0011]
Since the foam obtained by the method of the present invention has a uniform cell structure, it is suitable for a foam for skin care.Other than this, for example, a sponge for body washing containing glucomannan as a main component, collagen, etc. It can also be used as a sponge for cell culture mainly comprising.
[0012]
In order to insolubilize the foam obtained by the method of the present invention in water, a crosslinking component is previously added to an aqueous solution or suspension of a hydrophilic natural polypeptide such as collagen or chitosan and / or a hydrophilic natural polysaccharide. After that, heat treatment may be performed after vacuum drying by the above method. In the case where the solubility in water changes due to a change in pH such as collagen or chitosan, a water-insoluble hydrogel is obtained by changing the pH of an aqueous solution or suspension. To obtain a water-insoluble foam, and to obtain an aqueous solution or suspension of a hydrophilic natural polypeptide such as collagen or chitosan or / and a hydrophilic natural polysaccharide by vacuum drying according to the above method. The water-insoluble foam can also be obtained by immersing the foam in a non-aqueous solution containing a suitable crosslinking component or a water-insolubilizing component and then drying.
[0013]
Here, examples of the hydrophilic natural polypeptide include collagen, casein, albumin, elastin, and silk protein.Examples of the hydrophilic polysaccharide include chitosan, cellulose, cellulose derivatives, chondroitin sulfate, alginic acid, and glucomannan. , Pectin and the like, but are not limited thereto.
[0014]
Additives can be added to the present invention. Examples of such additives include plasticizers and fragrances for improving the commercial properties of the foam, and xanthan gum, carrageenan, and galacton, which have the effect of preventing the growth of ice crystals added during stirring and cooling. Thickeners such as mannan, emulsifiers such as polyethylene glycol lauryl ether, polyethylene glycol stearyl ether, and sucrose fatty acid ester; oligosaccharides such as palatinose, maltose, and lactose; and sugar alcohols such as glycerol, erythritol, sorbitol, and maltitol. be able to. In particular, the latter thickeners and emulsifiers, oligosaccharides and sugar alcohols are effective for obtaining fine ice crystals after freezing.
[0015]
【Example】
Example 1
After defatting salmon skin, polyethylene glycol stearyl edel (Brij78, HLB = 15.3) was added as an emulsifier to 1800 g of an acid-soluble collagen solution (pH = 3.1, solid content = 0.7%) obtained by acetic acid extraction. Sigma (Aldrich Japan Co., Ltd.) (5.4 g) was added, and the mixture was stirred and mixed with a homogenizer at 7000 rpm for 10 minutes in a state where the pressure was reduced to 10 torr or less in order to prevent air bubbles from entering while cooling the container with 5 ° C. cooling water. A collagen solution was obtained. The temperature of the obtained collagen solution was 7 ° C. 600 g of this collagen solution was poured into a container kept cool at -20 ° C, and cooled while stirring at 100 rpm for 20 minutes. The cooled collagen solution had a sherbet-like uniform ice crystal.
[0016]
Next, the sherbet-shaped collagen solution thus obtained was poured into a stainless steel mold having a thickness of 150 mm × 150 mm × 10 mm, and was compressed from above with a 2 mm-thick aluminum plate to completely fill the mold. The filled mold was quickly placed in a shock freezer adjusted to -60 ° C and left for 3 hours to completely freeze. Thereafter, the frozen product was taken out of the mold, dried by a freeze dryer, and then subjected to dehydration crosslinking in a vacuum oven at 1 torr and 105 ° C. for 48 hours to obtain a collagen foam. As shown in FIG. 1, the cross section of the obtained foam was good having uniform and fine cells. The figure shows a cross section in the thickness direction of the foam, and the length indicated by the section of the arrow indicates 1 mm. The same applies to those shown in FIG. 2 below.
[0017]
Example 2
20 g of crab derived chitosan having an average particle size of 100 μm and a deacetylation rate of 85%, 2 g of polyethylene glycol stearyl edel (Brid78, HLB = 15.3, melting point 44 to 46 ° C .: Sigma-Aldrich Japan Co., Ltd.) as an emulsifier, and dried 3 g of glycerin as a plasticizer was added to 1000 g of distilled water, dispersed well, and stirred and mixed on a 60 ° C. water bath for 1 hour. Next, 1N hydrochloric acid was gradually added to adjust the pH to 5.3, and then ethylene glycol diglycidyl ether (epoxy equivalent = 113) was added as a calculated value so that the degree of crosslinking with chitosan was 5%. After rapidly stirring and mixing, the mixture was heated on a hot water bath at 60 ° C. for 3 hours and allowed to cool at room temperature to obtain a hydrogel gel of epoxy-crosslinked chitosan.
[0018]
After cooling the obtained hydrogel product of chitosan to 5 ° C. in a refrigerator, 600 g of the hydrogel product was poured into a container kept at −20 ° C., and cooled while stirring at 100 rpm for 20 minutes. . The cooled gel was a sherbet-like and had uniform ice crystals. Next, the sherbet-shaped gel was poured into a 150 mm × 150 mm × 10 mm thick stainless steel mold, compressed from above with a 2 mm thick aluminum plate, and filled into the mold. Then, the filled mold was quickly placed in a shock freezer adjusted to -60 ° C and left for 3 hours to completely freeze. Thereafter, the frozen product was taken out of the mold and dried by a freeze dryer to obtain a chitosan foam. The cross section of the obtained foam was uniform and good with fine bubbles. A foam sheet obtained by slicing this chitosan foam into a size of about 1 mm using a cutter knife has an apparent density of 0.03 g / cm3, a water absorption of 15 times its own weight, and has a smooth surface and good water retention. It had excellent properties.
[0019]
Comparative Example 1
The procedure was performed in the same manner as in Example 1, except that the collagen solution of Example 1 was injected into a mold without forming the sherbet. As shown in FIG. 2, the cross section of the obtained foam had a bubble structure in which ice crystals grew in a needle shape, and was inferior with uneven and coarse cells.
[0020]
Comparative Example 2
The same procedure as in Example 1 was carried out except that the collagen solution of Example 1 was injected into a mold without forming a sherbet, and immersed in ethanol cooled to -40 ° C instead of a shock freezer. The cross section of the obtained foam had a bubble structure in which ice crystals grew like needles as in Comparative Example 1, and was poor with uneven cells.
[0021]
Further, in the embodiment of the present invention, as a material for producing a foam, an example in which marine collagen which is an example of a hydrophilic natural polypeptide is taken, and a chitosan which is an example of a hydrophilic natural polysaccharide is taken up. By way of example only, the material is not limited to this, and foams can be made using more than one type of material.
[0022]
【The invention's effect】
According to the invention according to claim 1, a hydrophilic natural polypeptide or / and a hydrophilic natural polysaccharide are formed from a low-viscosity viscous substance, have a uniform cell structure, are excellent in feel and water retention, and have good appearance. A foam can be obtained.
[0023]
According to the inventions according to the second to fourth aspects, a foam insolubilized in water can be obtained. According to the invention according to the fifth aspect, a foam having high commercial properties can be obtained.
According to the invention of claim 6, fine ice crystals can be obtained after freezing.
[0024]
According to the inventions according to claims 7 and 8, it is possible to obtain a foam having excellent feel and good compatibility with the skin, and marine collagen and chitosan are compared with other materials. There is a feature that materials are easily available.
[Brief description of the drawings]
FIG. 1 is a photograph showing a cross section of Example 1.
FIG. 2 is a photograph showing a cross section of Comparative Example 1.

Claims (8)

Cooling and stirring an aqueous solution or suspension of a hydrophilic natural polypeptide or / and a hydrophilic natural polysaccharide into a sherbet, filling a mold, molding, freezing, and vacuum drying. A method for producing a foam, characterized in that: A crosslinking component is added in advance to an aqueous solution or suspension of a hydrophilic natural polypeptide or / and a hydrophilic natural polysaccharide, and then heat-crosslinked to form a water-insoluble hydrogel, which is then stirred. 2. The foam according to claim 1, wherein the foam is cooled while forming into a sherbet, filled in a mold, molded, frozen, and then vacuum-dried, or vacuum-dried and then heat-crosslinked. Manufacturing method. After changing the pH of an aqueous solution or suspension of a hydrophilic natural polypeptide or / and a hydrophilic natural polysaccharide to form a water-insoluble hydrogel, the mixture is cooled while stirring. A method for producing a foam according to claim 1. The method for producing a foam according to claim 1, wherein after drying in vacuum, the foam is immersed in a non-aqueous solution containing a crosslinking component or a water-insolubilizing component, and then dried. The method for producing a foam according to any one of claims 1 to 4, wherein a plasticizer, a fragrance, and the like are added. The method for producing a foam according to any one of claims 1 to 5, wherein a thickener and an emulsifier having an effect of preventing ice crystal growth are added during stirring and cooling. The method for producing a foam according to any one of claims 1 to 6, wherein the hydrophilic natural polypeptide is marine collagen. The method for producing a foam according to any one of claims 1 to 6, wherein the hydrophilic natural polysaccharide is chitosan.

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