JPH10263374A - Filter for filtering fermented drink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a porous membrane, high in strength and having a specified physical property, capable of prolonging the life since the membrane has an excellent filtering performance and a high resistance to backward washing, and the membrane is allowed to be treated by a chemical liquid washing.sterilization using acid and alkali and so very stable, and in which the fear of falling and elution of a foreign matter is reduced and which is suitable as a filter for filtering a fermented drink, especially beer. SOLUTION: This filter for filtering the fermented drink is composed of a high mol.wt. polyolefin and has the following characteristics. (1) 0.1-3.0 μm max. fine pore diameter, (2) 1.0-10.0 kg/cm<2> water bubble point, (3) >=1000 l/(m<2> .hr) water permeantion volume, (4) >=99% inhibition ratio of a polystyrene ratex having 1.07 μm grain size, (5) 1-100 μm thickness and (6) >=3 kg/cm<2> resistance to filter pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for filtering fermented beverages, and more particularly to a method for filtering beer during the production of beer characterized by using a specific high molecular weight polyolefin porous membrane. About the filter.

[0002]

2. Description of the Related Art As a disinfection / separation operation generally used for a liquid, a method such as centrifugation, washing, and filtration is used. Among them, in the filtration of beverage products, it is known that the filtration operation is excellent in terms of simplicity of the process and mass productivity. Methods that have been used as filtration operations include cake filtration using diatomaceous earth as a filter aid, bed filtration using diatomaceous earth-containing fibers and a filtration layer, and membrane filtration.

[0003] Among them, membrane filtration is excellent in filtration accuracy, does not require a preliminary operation before filtration, can perform normal processing immediately after operation, and can be operated unattended, and is difficult to regenerate, and is difficult to regenerate. There is an advantage that no adverse effect on the environment is easily exerted because no filter aid is used. BACKGROUND ART In recent years, microfiltration membranes are used for liquid filtration and sterilization for use in the electronics industry, medicines, foods, and the like, and their use and usage are increasing year by year.

[0004] As raw materials for general microfiltration membranes, usually, cellulose acetate, cellulose mixed ester, polyvinyl chloride, polyamide, polycarbonate, nitrocellulose, triacetyl cellulose, PTFE, polyimide, polyurethane, polysulfone, cross-linked polyvinyl alcohol, Polymers such as polypropylene and polyethylene are used.

Various methods have been used to produce a microfiltration membrane. For example, a polymer and an incompatible component are blended and stretched to form pores at the interface with the incompatible component. To remove pores by cold stretching a film with a specific structure that has been melt-extruded, or to form a paste from polymer particles and a solvent, stretch after compression, and remove the solvent. There are a method of forming pores by cooling the polymer solution under specific conditions or removing the solvent, and a method of adding a plasticizer to the polymer and extracting it with a solvent after molding to form pores. The pore size distribution is appropriately adjusted in the production process of the porous film depending on the size of the particles to be removed, the stretching ratio, and the like.

[0006] These microfiltration membranes are also widely used in the field of beverage products, for example, disinfection in the production of sake, clarification of fruit juice and wine, filtration after fermentation of vinegar, and the like.
It is used for the production of mineral water. Similarly, membrane filtration using a porous membrane made of a polymer material and having a specific pore size has been proposed for fermented beverages, particularly beer disinfection and separation and purification, which has a significant effect on beer quality improvement. In the process of producing beer, the separation and disinfection of undesired substances in the quality of products is a very important step. The undesired substances in quality include microorganisms, yeasts, turbid substances, etc. harmful to beer.

[0007] In the filtration filter, the performance of inhibiting yeast and bacteria can be improved by making the pore size of the porous film as small as possible. On the other hand, as the filtration flow rate, one of the processing capacities, becomes smaller as the pore size decreases, particles (turbid substances, etc.) smaller than the yeast present in the liquid adhere to the pores of the porous film, and the liquid flow rate increases. Gradually worsens the road. Therefore, in view of the balance between these two performances, a filter having a maximum pore diameter of about 0.45 to 0.65 μmm is used as an ordinary filter for beer filtration.

[0008] Conventionally, the performance required as a filtration membrane for beverage products including beer is that the flavor of foods and beverages is not impaired, the processing capacity, that is, the processing capacity per unit area is excellent, and clogging is prevented. It has been generally said that it is cheap, that it is economical in filtration cost such that it can be reused repeatedly only by washing with hot water or the like after clogging, and that steam sterilization is possible.

Various methods have been proposed to improve these performances. For example, Japanese Patent Application Laid-Open No. Hei 1-270906
In Japanese Patent Application Laid-Open Publication No. H11-176, a microporous membrane for beer filtration comprising a polyether sulfone having a pore diameter in the range of 0.1 to 1.2 μm and a hydrophilizing agent is proposed. Japanese Patent Publication No. 5-5532 discloses a membrane for increasing the filtration life of beer, in which the anisotropy of the pore diameter comprising polyether sulfone and a hydrophilizing agent is from 1.5: 1 to 2.5:
No. 1 discloses a membrane having a water bubble point of 1.2 to 2.5 bar. In addition, Japanese Patent Application Laid-Open No. 3-117475
Japanese Patent Application Laid-Open Publication No. H11-163,887 discloses a membrane having a surface coating composed of a polyacrylic acid derivative or a polymethacrylic acid derivative on the surface of a filtration membrane, and the filtration membrane is periodically filtered with an alkaline sodium hypochlorite solution during filtration of beer. A method for cleaning is disclosed. Further, JP-A-7-222917 discloses a filtration membrane having an anisotropic structure layer in which the pore size changes continuously in the thickness direction and an isotropic structure layer in which the pore size is substantially uniform in the thickness direction. Disclosed is a method of treating a membrane with a chemical solution that degrades polymers and proteins.

[0010] In general, the method of washing and sterilizing a filtration filter differs depending on the raw material constituting the filter. For example, in the case of cellulose acetate, a combination of washing with water, washing with an enzyme detergent, washing with an acid, sterilization with peracetic acid, polysulfone, For polyacrylonitrile, a combination of water washing, alkali / acid washing, and sterilization with sodium hypochlorite is used, and for polyamide, a combination of water washing, alkali / acid washing, and sterilization with metabisulfite is used. However, in practice, washing with only warm water is often performed due to the risk of elution of impurities from these porous films.

[0011] By the way, in recent years, with the establishment of the PL law, the responsibility of the manufacturer for products has become very important.
Along with the above-mentioned required performance, the requirements for its completeness (for example, the ability to inhibit bacteria) and its safety (dropping and elution of foreign substances) have become more stringent than ever. As mentioned above,
Various filters have been proposed as filter materials for beer, but for filtration of fermented beverages that satisfy all of high filtration performance (bactericidal and particle removal performance and high throughput), long filtration life, and prevention of falling off and elution of foreign substances. There has been no filter for beer filtration, especially a fermented alcoholic beverage.

[0012]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fermented beverage, especially a fermented alcoholic beverage, which has excellent filtration performance in the beer production process, has a high backwashing resistance, and has a chemical solution containing an acid or alkali. An object of the present invention is to provide a filter for filtration that can be washed and sterilized, can extend the life thereof, and is less likely to drop off or elute foreign substances due to acid / alkali treatment.

[0013]

Means for Solving the Problems The present invention has been proposed in order to achieve the above-mentioned object, and a porous membrane having specific physical properties using a high molecular weight polyolefin resin as a raw material,
The present invention has been completed based on the findings found by the present inventors, which are extremely suitable for solving the above problems.

That is, according to the present invention, it is composed of a high molecular weight polyolefin, (1) having a maximum pore diameter of 0.1 to 3.0 μ; and (2) having a water bubble point of 1.0 to 10.0 kg /.
cm ^2; (3) water permeability is 1,000 l / (m ² · hr) or more; (4) the rejection of polystyrene latex having a particle size of 1.07μ 99% or more; (5) has from 1 to a thickness of 100 [mu] m; ( 6) A filter for filtering fermented beverages having a filtration resistance of 3 kg / cm ² or more is provided.

Further, according to the present invention, there is provided the filter for filtering a fermented beverage, wherein the high molecular weight polyolefin has an intrinsic viscosity [η] of 4 dl / g or more.

According to the present invention, there is provided the above-mentioned filter for filtering fermented beverages, wherein the high-molecular-weight polyolefin is polyethylene.

Further, according to the present invention, the fermented beverage comprises:
The filter for filtering fermented beverages which is beer is provided.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a raw material for a high molecular weight polyolefin porous film constituting a filter for filtering a fermented beverage of the present invention, a method for producing the same, and a filter for beer filtration as a typical use thereof will be described.

<Raw Materials> The high molecular weight polyolefin used in the present invention refers to a copolymer obtained by copolymerizing ethylene, propylene and α-olefins of hydrocarbons 4 to 8 singly or in combination of two or more. .
Particularly preferred among these are ethylene homopolymers. The molecular weight is 4 d in intrinsic viscosity [η] during molding.
1 / g or more, preferably 4 to 25 dl / g;
In particular, for the purpose of obtaining a porous film having excellent filtration pressure,
The intrinsic viscosity [η] is preferably 5 to 20 dl / g, and 8
To 20 dl / g is particularly preferred. If the intrinsic viscosity [η] exceeds 25 dl / g, as described below, the melt viscosity tends to be too high when the film before the porous treatment is formed, resulting in poor moldability.

<Production method of ultra-high molecular weight polyolefin porous film> As a production method of the ultra-high molecular weight polyolefin porous film, for example, International Publication WO93 / 12920 proposed by the present inventors and JP-A-8-13
The method disclosed in Japanese Patent No. 4253 can be used. In these methods, a sheet is formed from a mixture of an ultrahigh molecular weight polyolefin and a plasticizer (for example, paraffin wax), stretched before or after extraction of the plasticizer, and the like, and a porous film is obtained by removing the plasticizer. Is the way.

In the present invention, these methods can be used. However, the plasticizers and solvents used are those which are stable to acids, alkalis and the like, and these plasticizers and solvents are substantially used after the formation of the porous film. It is necessary to make it under the condition that it does not remain. Substantially, based on the amount of plasticizer added,
Mean less than 1% by weight. Also, Japanese Patent Application Laid-Open
In the present invention, a method for obtaining a porous film of ultra-high-molecular-weight polyethylene by simply hot stretching without adding a plasticizer or a solvent, which is disclosed in JP-A-1144671, is also a preferable production method in the present invention.

<Beer Filtration Filter> The maximum pore diameter of the beer filtration filter of the present invention is 0.1 to 3.0 μm, preferably 0.2 to 2.0 μm, and more preferably 0.3 to 1.5 μm. It is. If the maximum pore diameter is too large, bacteria and yeasts may be permeated. If the maximum pore diameter is too small, a sufficient filtration treatment amount may not be obtained. Water bubble point is 1.0 to 10.0k
g / cm ² , preferably 2.0 to 9.0 kg / cm
² , more preferably 3.0 to 8.0 kg / cm ² . The water bubble point is related to the maximum pore diameter. If the water bubble point is too low, bacteria and yeasts may permeate. If the water bubble point is too high, a sufficient filtration treatment amount may not be obtained.

The water permeability is 1000 liters / (m ² · h)
r) or more, preferably 1500 l / (m ² · h)
r) or more, more preferably 2000 liters / (m ²
hr) or more. The rejection of polystyrene latex having a particle size of 1.07 μm is 99% or more, preferably 100%.
It is. The thickness is 1 to 100 μm, preferably 1 to 50 μm, more preferably 1 to 30 μm. The filtration pressure is 3 kg / cm ² or more, preferably 4 k / cm ²
g / cm ² or more, more preferably 6 kg / cm ² or more.

The ultrahigh molecular weight polyolefin porous film used in the filter for beer filtration of the present invention can be hydrophilized by addition of a monomer having a hydrophilic group or plasma treatment. Since there is a possibility that impurities such as decomposition products may be generated at the time of washing or the like, it is preferable not to perform the treatment. However, at the start of filtration, the filtration filter of the present invention, a liquid that is safe for beer filtration,
For example, after impregnating with ethanol or a mixture of ethanol and water, it may be used for filtration.

The filter for beer filtration of the present invention can be combined with a prefilter and processed into a module such as a pleated module or a spiral module. When the filter for beer filtration of the present invention is clogged by filtration, it can be washed and sterilized by a conventionally proposed agent such as an acid, an alkali or an enzyme solution. As described above, the embodiment of the filter for filtering fermented beverages of the present invention, which is a preferred application as a filter for filtering beer, has been described. However, the filter of the present invention is preferably used for fermented alcoholic beverages such as sake, shochu, wine, and whiskey. It can be used not only as a filter for filtration, but also as a filter for filtering fermented beverages such as soy sauce, vinegar and lactic acid beverages.

The above characteristics of the present invention were measured by the following methods.

<Intrinsic viscosity> The intrinsic viscosity in the present specification is:
It is a value measured at 135 ° C. in a decalin solvent. The measurement is performed based on ASTM D0420.

<Maximum Pore Diameter> The maximum pore diameter is determined by a mercury porosimeter manufactured by Yuasa Ionics (model Autoscan 3).
The maximum value of the pore diameter measured in 3) was used.

<Water Bubble Point> The water bubble point was measured according to ASTM F316-70. The measurement was performed after the porous film was immersed in a 1: 1 mixture of ethanol and water for 10 minutes and washed with water for 30 minutes. However, when measurement was not possible due to rupture of one porous film, measurement was performed with two sheets superposed, and the measured value was corrected for the film pressure.

<Water permeability> The measurement of ethanol and water was performed as follows:
The porous film was immersed in one mixed solution for 10 minutes, and washed with water for 30 minutes. The measuring device is ADVANTEC TS
Using a U-90B filtration test device, a filtration pressure of 2 kg /
After water permeation for 1 minute at cm ² , water permeation was performed for 10 minutes, and the amount was measured.

<Rejection of Polystyrene Latex> The rejection of polystyrene latex was measured by the following method.
A 0.01% by volume aqueous dispersion of polystyrene latex (manufactured by Dow Chemical Company) having a particle size of 1.07 μm was used as a stock solution.
This stock solution was filtered through the porous film of the present invention under a pressure difference of 5 kg / cm ² , and this was used as a filtrate. For the stock solution and the filtrate, the concentration of polystyrene latex was measured with a UV MPS-2000 type measuring device manufactured by Shimadzu Corporation, and the rejection was calculated from the concentrations before and after filtration.

<Thickness> The thickness was measured with a film thickness measuring instrument Miniax (model DH-150) manufactured by Tokyo Seimitsu Co., Ltd.

<Anti-filtration pressure> Pressure was applied in the same manner as in the measurement of the water bubble point, and the pressure at which one film was broken was defined as the anti-filtration pressure.

[0034]

According to the present invention, by using a high-strength porous membrane having specific physical properties, which is obtained from a high-molecular-weight polyolefin resin as a raw material, it has excellent filtration performance and is resistant to backwashing. Beer, which has a high pressure, can be washed and sterilized with an acid or alkali, and is extremely stable, can have a long life, and further reduces the risk of falling off or elution of foreign substances. Filtration filters for fermented alcoholic beverages such as sake, shochu, wine, whiskey, and so on, as well as fermented beverages such as soy sauce, vinegar, and lactic acid beverages,
In particular, a porous membrane suitable as a filter for beer filtration can be provided.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
This example discloses a preferred embodiment of the present invention and is not intended to be limiting.

Example 1 Intrinsic viscosity [η] = 16.5 d
A T-die sheet was formed from a mixture of 1 / g of high molecular weight polyethylene and paraffin wax (melting point 69 ° C.).
However, the mixing ratio of the raw materials was high molecular weight polyethylene: paraffin wax = 3: 7. The paraffin wax is then extracted for 10 minutes in n-decane at 80 ° C.
Drying was carried out in an air oven at ℃. Extraction and drying were performed with the sheet in the longitudinal direction fixed. continue,
Biaxial stretching was performed with a biaxial stretching machine manufactured by Toyo Seiki to obtain a porous film. The residual amount of paraffin wax and n-decane after drying was 1% by weight or less. Table 1 below shows the physical properties of the obtained porous film.

[0037]

Example 2 Intrinsic viscosity [η] = 16.5 d
1 / g high molecular weight polyethylene, blown film of 45 μm thickness (draft ratio: 8.7, expansion ratio: 8)
It was created. Next, with the film fixed on all sides, the film was treated in n-paraffin (melting point: 28.1 ° C.) at 128 ° C. for 2 minutes, and then immersed in n-hexane for 2 hours to obtain n-paraffin.
Paraffin is completely extracted, n-hexane is dried in an air oven, and further using a biaxial stretching machine manufactured by Toyo Seiki,
A fixed width uniaxial stretching was performed in air at a stretching speed of 1.5 m / min to obtain a porous film. The residual amount of n-paraffin and hexane in the obtained film was 1% by weight or less based on the total amount of the film. Table 2 shows each physical property of the obtained porous film.

[0039]

Example 3 A beer for filtration was prepared based on a handmade beer manual (edited by the Japan Homebrewing Recommendation Federation, published by Nihon Bungeisha Co., Ltd.). That is, a malt extract can (907 g of a beer raw pail lager can) was placed in 2 liters of boiling water, 700 g of white sugar was added, and the mixture was boiled for 5 minutes. This solution was then transferred to 10 liters of water in a fermentation vessel to make a total volume of 16 liters. Further, the temperature 23
Brewer's yeast (Eile yeast ED)
ME 11.5 g), and stir the solution every two days.
It was prepared by allowing it to stand for one week. Using the prepared beer for filtration, using the porous film of Sample No. 2,
Filtration was performed at a filtration pressure of 5 kg / cm ² . Filtration was performed until the water permeation amount became substantially zero, and the filter for filtration was taken out of the filtration device. As shown in FIG. 1 (1000 × (a), 5000 × (b)) showing the result of observing the surface of the filtration filter with a scanning electron microscope, brewer's yeast was observed on the filter cake surface. In addition, on the back surface of the filter, turbid substances closing the pores were observed, but brewer's yeast was not observed at all (FIGS. 2A and 2B).
In addition, an electron microscope photograph (1000
3) is shown in FIG. Further, Table 3 shows the physical properties of the porous film after the filter after the filtration was washed with a strong acid (10% hydrochloric acid) and a strong alkali (5% aqueous sodium hydroxide solution).

[0041] As can be seen from the above results, it was confirmed that the film properties hardly changed even after filtration and acid / alkali washing.

[Brief description of the drawings]

FIG. 1 is an electron micrograph showing the surface state of a filter after beer filtration in Example 3.
(A) is at a magnification of 1000 times and (b) is at a magnification of 5000 times.

FIGS. 2A and 2B are electron micrographs showing the state of the back surface of the filter of FIG. 1, wherein FIG.
Depends on magnification.

FIG. 3 is an electron micrograph (× 1000) showing a state before filtration of a porous film having a sample number.

Claims (4)

[Claims] 1. A high-molecular-weight polyolefin,
A filter for filtering fermented beverages having the following characteristics. (1) a maximum pore diameter of 0.1 to 3.0 μ; (2) a water bubble point of 1.0 to 10.0 kg /
cm ^2; (3) water permeability is 1,000 l / (m ² · hr) or more; (4) the rejection of polystyrene latex having a particle size of 1.07μ 99% or more; (5) has from 1 to a thickness of 100 [mu] m; ( 6) The filtration pressure resistance is 3 kg / cm ² or more; 2. The filter for filtering a fermented beverage according to claim 1, wherein the high molecular weight polyolefin has an intrinsic viscosity [η] of 4 dl / g or more. 3. The filter for filtering a fermented beverage according to claim 1, wherein the high molecular weight polyolefin is polyethylene. 4. The fermented beverage according to claim 1, wherein the fermented beverage is beer.
The filter for filtering fermented beverages according to the above.