JP6824566B2 - Hydrophilization method of continuous porous body and hydrophilic continuous porous body using the hydrophilicization method - Google Patents

Description

The present invention relates to a method for hydrophilizing a continuous porous body and a hydrophilic continuous porous body using the method for hydrophilizing the continuous porous body.

The continuous porous body is used as a sheet or a pad in medical, cosmetic, hygienic, and the like. There is an extraction method as one of the methods for producing a continuous porous body. The extraction method is a method in which a pore-forming material is kneaded and dispersed in a main material to form a predetermined shape, and then the pore-forming material is removed to form a continuous porous body.

Most of the thermoplastic resins used as the main material show hydrophobicity, and in particular, a continuous porous body made of an olefin resin such as an ethylene-vinyl acetate copolymer has strong hydrophobicity and is used for applications requiring hydrophilicity. It wasn't suitable. Examples of those required to be hydrophilic include a cosmetic pad, a water-absorbing sponge, a water-absorbing roller, a liquid coating body, a liquid holding body, a swab, a wipe, and a moisture-absorbing material.

Further, by impregnating a continuous porous body formed of an olefin resin such as an ethylene-vinyl acetate copolymer with a solution containing a nonionic surfactant and drying it, the surface of the continuous porous body is subjected to nonionic surfactant. It has been proposed to attach an agent to increase hydrophilicity (Patent Document 1).

However, in the conventional continuous porous body made of an olefin resin having a nonionic surfactant adhered to the surface, the nonionic surfactant may fall off from the continuous porous body during use, and the hydrophilicity may decrease. is there. In particular, for applications such as liquid cosmetic pads that come into contact with the skin and are rubbed, the nonionic surfactant is rubbed off from the surface of the continuous porous body made of olefin resin, and the hydrophilicity tends to decrease. ..

Japanese Unexamined Patent Publication No. 2005-187529

The present invention has been made in view of the above points, and is a method for making a continuous porous body hydrophilic, and a hydrophilic continuous porous body obtained by using the method for making a continuous porous body, which can maintain hydrophilicity for a long period of time. The purpose is to provide the body.

In the invention of claim 1, an olefin-based elastomer, polypropylene, a pore-forming material, and a nonionic surfactant are heated and kneaded to form the molded product, and the pore-forming material is used as a solvent from the obtained molded product. eluting said hydrophilic continuous porous body nonionic surfactant remains a resulting Ru hydrophilizing method, the pore forming material, and soluble organic substances with solubility inorganic soluble in the same solvent It is characterized in that the soluble inorganic substance and the soluble organic substance are mixed and used in combination .

In the invention of claim 2, in claim 1, the ratio of the soluble inorganic substance to the soluble organic substance is: soluble inorganic substance: soluble organic substance = 96.3: 3.7 to 11:89 (weight percentage wt%). It is characterized by being.

The invention of claim 3 is characterized in that, in claim 1 or 2, the polypropylene is composed of at least one of homopolypropylene, random polypropylene, and block polypropylene.

According to the invention of claim 4, in any one of claims 1 to 3, the nonionic surfactant is polyoxyethylene having an alkyl carbon number of 15 to 40 and an oxyethylene degree of polymerization of 2 to 8. It is characterized by being an alkyl ether.

The invention of claim 5 is a hydrophilic continuous porous body obtained by the hydrophilization method according to any one of claims 1 to 4, and includes an olefin elastomer, polypropylene, and a nonionic surfactant. It is characterized in that the nonionic surfactant remains in the continuous porous body made of the mixed resin.

According to the invention of claim 1, since the olefin-based elastomer, polypropylene, the pore-forming material, and the nonionic surfactant are heated and kneaded for molding, the matrix composed of the olefin-based elastomer and polypropylene is not formed. The ionic surfactant is dispersed, and the nonionic surfactant can be present and remain in the continuous porous body, and good hydrophilicity can be maintained for a long period of time. Further, the continuous porous body made of olefin elastomer and polypropylene is more resistant to chemicals and hydrolysis than the continuous porous body made of ethylene-vinyl acetate copolymer resin (EVA resin) or thermoplastic polyurethane resin (TPU resin). It is suitable for medical use, cosmetics, hygiene, etc. because it has excellent properties and resistant yellowing, and there are few restrictions on the usage environment.

According to the invention of claim 1 , since the pore-forming material is composed of a soluble inorganic substance and a soluble organic substance that can be dissolved in the same solvent, the viscosity of the olefin-based elastomer and polypropylene is lowered due to the presence of the soluble organic substance during kneading. It is possible to disperse the nonionic surfactant in the olefin-based elastomer and polypropylene.

According to the invention of claim 3, by using at least one of homopolypropylene, random polypropylene, and block polypropylene, the rubber component of the EPR layer can be mixed, and the polypropylene is flexible and has low hardness, hydrophilic continuous porous. It is suitable for applications where a body can be obtained and flexibility and low hardness are required.

According to the invention of claim 4, since the nonionic surfactant is a polyoxyethylene alkyl ether having an alkyl carbon number of 15 to 40 and an oxyethylene degree of polymerization of 2 to 8, it is a pore-forming material. A nonionic surfactant can be left in the continuous porous body when the continuous porous body is formed by eluting the mixture to obtain a hydrophilic continuous porous body capable of maintaining good hydrophilicity for a long period of time. be able to.

According to the invention of claim 5, since the nonionic surfactant remains in the continuous porous body made of the mixed resin containing the olefin elastomer, polypropylene and the nonionic surfactant, it has good hydrophilicity. Sex can be maintained for a long period of time.

It is a table which shows the structure and the measurement result of Example 1 to Example 6. It is a table which shows the structure and the measurement result of Example 7 to Example 13. It is a table which shows the structure and the measurement result of the comparative example 1 to the comparative example 3. It is a table which shows the structure and the measurement result of Reference Example A to Reference Example C.

Hereinafter, a method for hydrophilizing a continuous porous body according to the present invention and an embodiment of a hydrophilic continuous porous body using the hydrophilic method will be described.
The hydrophilic continuous porous body of the present invention is a porous body composed of only a skeleton without a pore membrane, and is composed of a mixed resin containing an olefin elastomer, polypropylene, and a nonionic surfactant.

The hydrophilic continuous porous body made of the mixed resin is the production raw material of the production raw material when the production raw material composed of an olefin elastomer, polypropylene, a pore-forming material and a nonionic surfactant is 100 vol% by volume. It is 11 to 55 vol% with respect to 100 vol%. Regardless of the volume percentage, hydrophilicity is maintained as long as the nonionic surfactant remains. If the volume percentage is less than 11 vol%, the strength of the porous body cannot be obtained. If it exceeds 55 vol%, it becomes difficult to form an open cell structure in the entire porous body.

The olefin-based elastomer preferably has a melting point (Tm) in the range of 60 ° C. to 130 ° C. For example, ethylene-butene copolymer, ethylene-octene copolymer, α-olefin copolymer, olefin block copolymer and the like can be mentioned. The melting point is the temperature of the peak as measured by differential scanning calorimetry (DSC).
The amount of the olefin-based elastomer is 5.0 wt% to 29.0 wt%, more preferably 10 wt% to 20 wt%, based on 100 wt% of the production raw material.

The polypropylene preferably has a melting point (Tm) in the range of 130 ° C. to 170 ° C. In particular, at least one of homopolypropylene, random polypropylene, and block polypropylene is preferable. The melting point is the temperature of the peak as measured by differential scanning calorimetry (DSC).
The amount of polypropylene is 0.2 wt% to 4.0 wt%, preferably 0.3 wt% to 3.0 wt%, and more preferably 0.5 wt% to 2.0 wt%.

Examples of the nonionic surfactant include fatty acid glyceride, alkoxylated alkylphenol, polyoxyalkylene fatty acid ester, alkylpolyoxyethylene alcohol, polyoxyethylene alkyl ether, fatty acid amide and the like. The nonionic surfactant is not limited to one type, and a plurality of types may be used. The nonionic surfactant is not easily affected by ionic substances and can maintain good hydrophilicity for a long time. In particular, it is preferable to use a polyoxyethylene alkyl ether having an alkyl carbon number of 15 to 40 and an oxyethylene polymerization degree of 2 to 8 as a nonionic surfactant. Examples of the polyoxyethylene alkyl ether having an alkyl carbon number of 15 to 40 and a degree of polymerization of oxyethylene of 2 to 8 include NOF Corporation, product number: Nonion E-202S, Toyo Adre Co., Ltd., Unitox 420 and the like. Can be mentioned. The amount of the nonionic surfactant is preferably 0.3 wt% to 5.0 wt%, more preferably 0.6 wt% to 3.0 wt%.

Since the hydrophilic continuous porous body of the present invention is composed of a mixed resin containing an olefin elastomer, polypropylene and a nonionic surfactant, the resin constituting the skeleton of the continuous porous body is composed of a nonionic surfactant. Is dispersed and remains, and is less likely to fall off than when it is simply attached to the skeleton surface, and good hydrophilicity due to the nonionic surfactant can be maintained for a long period of time.

In producing the hydrophilic continuous porous body of the present invention, in addition to the olefin elastomer, polypropylene and nonionic surfactant, a soluble inorganic substance and a soluble organic substance are mixed as a pore-forming material.
The ratio of the olefin-based elastomer to the pore-forming material is not particularly limited as long as a continuous porous body can be formed. The weight percentage (wt%) is preferably olefin-based elastomer: pore-forming material = 4.8: 95.2 to 31:60, and more preferably in the range of 7:93 to 25:75.

The soluble inorganic substance is not particularly limited as long as it is a substance that can be dissolved in a solvent and eluted from the porous body. As the solvent, a solvent in which the soluble inorganic substance and the soluble organic substance are dissolved and the olefin elastomer and polypropylene are insoluble is used, and water is preferable. Sodium chloride, potassium chloride, calcium chloride, ammonium chloride, sodium nitrate, sodium nitrite, sodium acetate, potassium acetate, calcium acetate, sodium carbonate, potassium carbonate, calcium carbonate, hydrogen carbonate are examples of soluble inorganic substances that can be dissolved in water. Sodium and the like can be mentioned. The soluble inorganic substance is not limited to one type, and a plurality of types may be used. The amount of the soluble inorganic substance is preferably 9.1 wt% to 85.3 wt%, more preferably 25 wt% to 80 wt%.

As the soluble organic substance, a substance that can be dissolved in the same solvent as the solvent in which the soluble inorganic substance is dissolved is used. A more preferable soluble organic substance is an organic substance that can be dissolved in the same solvent as the solvent in which the soluble inorganic substance is dissolved and that can reduce the viscosity of the olefin elastomer and polypropylene during the production of the hydrophilic continuous porous body. is there. As the solvent for dissolving the soluble organic substance, water is preferable as in the case of the solvent for the soluble inorganic substance. As an example of a soluble organic substance that is water-soluble and can reduce the viscosity of an olefin-based elastomer and polypropylene, it is derived from one or more types of HO- (C ₂ H ₄ O) _n- H structures, and is specific. Is polyethylene glycol. The degree of polymerization is preferably 6 to 600, and more preferably 90 to 400, which is a room temperature liquid. The soluble organic substance is not limited to one type, and a plurality of types may be used. The amount of the soluble organic matter is preferably 3.3 wt% to 73.3 wt%, more preferably 5 wt% to 50 wt%.

The ratio of the soluble inorganic substance to the soluble organic substance is not particularly limited as long as it can form a continuous porous body. Soluble inorganic matter: soluble organic matter = 96.3: 3.7 to 11:89 by weight percentage (wt%), more preferably in the range of 85: 15-30: 70. In addition, an appropriate additive may be contained.

A method for producing the hydrophilic continuous porous body will be described. First, the olefin-based elastomer, the polypropylene, the nonionic surfactant, and the pore-forming material are heated and kneaded. The heating temperature is a temperature at which the resin material (olefin elastomer and polypropylene) can be melted, and is 100 to 200 ° C. The kneading device is not particularly limited, and examples thereof include a lab plast mill, a kneader, a twin-screw extruder, and a twin-screw roll. The nonionic surfactant may be mixed and dispersed in the polypropylene in advance, and then heated and kneaded together with the olefin elastomer and the pore-forming material.

In order to design the finally obtained hydrophilic continuous porous body, it is necessary to mix all the compounding components according to at least the volume percentage of the olefin elastomer and polypropylene, but the compounding components actually put into the kneader Is converted by the specific gravity of each component and input by weight. Further, at the weight percentage, it is difficult to imagine the structural and spatial roughness of the finally obtained hydrophilic continuous porous body. Moreover, the numerical range of each compounding component falls within the range of 0.1 to 100 when the volume percentage is used for the compounding design, but when converted to the weight percentage in consideration of the specific gravity, the numerical range of each compounding component is. , Wider and more complicated formulation design. Incidentally, the specific gravity of the olefin-based elastomer is 0.893, but the specific gravity of the water-soluble inorganic substance is 2.16.

The kneaded body obtained by heating and kneading is formed into a predetermined shape. The shape to be molded is not particularly limited, and examples thereof include a sheet shape and a roll shape. The molding method is not particularly limited, and examples thereof include press molding, extrusion molding, injection molding, and calender molding.
After forming the molded body, the soluble inorganic substance and the soluble organic substance are eluted (extracted) from the molded body with a solvent to obtain a hydrophilic continuous porous body. The solvent used is one in which the soluble inorganic substance and the soluble organic substance are dissolved, and the olefin elastomer and the polypropylene are insoluble. The method for eluting the bubble forming material with the solvent is not particularly limited, but it can be carried out, for example, by immersing the molded product in the solvent for a predetermined time and then taking it out, or by spraying the solvent on the molded product. A part of the soluble organic substance may remain in the molded product. When water is used as the solvent, the soluble inorganic substance is eluted (extracted) from the molded body and then dried to remove water from the hydrophilic continuous porous body.

The nonionic surfactant remains in the produced hydrophilic continuous porous body, and good hydrophilicity can be obtained over a long period of time. The nonionic surfactant remaining in the hydrophilic continuous porous body can be confirmed by FTIR (Fourier Transform Infrared Spectroscopy) spectroscopy and LCTOFMS.

Hydrophilic continuous porous bodies were produced by blending the following substances with the examples and comparative examples in Tables 1 and 2.
・ Olefin-based elastomer: Part number; Toughmer 4090N, manufactured by Mitsui Chemicals Co., Ltd. ・ Homopolypropylene: Part number: PM600A, manufactured by Sun Aroma Co., Ltd. ・ Block polypropylene: Product number: J750HP, manufactured by Prime Polymer Co., Ltd. Made by Sun Aroma Co., Ltd. ・ Polyethylene: Part number; Novatec LL UJ960, manufactured by Nippon Polyethylene Co., Ltd. ・ Surfactant 1: Polyoxyethylene alkyl ether (nonionic surfactant), number of carbon atoms of alkyl group: R = 20, Degree of polymerization: n = 6
Surfactant 2: Polyoxyethylene alkyl ether (nonionic surfactant), alkyl group carbon number: R = 36, degree of polymerization: n = 4
-Surfactant MB1: Homopolypropylene (product number; PM600A, manufactured by Sun Aroma Co., Ltd.) is 40% by weight, surfactant 1 is 30% by weight, surfactant 2 is 30% by weight, and a biaxial continuous extruder is used. A masterbatch was created using it.
-Surfactant MB2: Linear low-density polyethylene (product number; Novatec LL UJ960, manufactured by Nippon Polyethylene Co., Ltd.) is 40% by weight, surfactant 1 is 30% by weight, and surfactant 2 is 30% by weight. A masterbatch was prepared using a shaft continuous extruder.
・ Water-soluble inorganic substance: Product name; Hakuho salt, manufactured by Hakata Salt Company Co., Ltd. ・ Water-soluble organic substance: Product number: PEG-6000P, manufactured by Sanyo Chemical Industries, Ltd.

In the production of each Example and each Comparative Example, the substances were first mixed in the proportions shown in FIGS. 1 to 4 and heated and kneaded with a lab plast mill (model name: 10C100, Toyo Seiki Co., Ltd.). The heating / kneading conditions are a lab plast mill rotation speed of 50 rpm, a temperature of 170 ° C., and a kneading time of 10 minutes. The obtained kneaded product was molded into a sheet of 100 mm × 100 mm × 2 mm by a manual hydraulic heating press (model name: 180C, Imoto Seisakusho Co., Ltd.). Next, the obtained sheet was immersed in a water tank left at an environmental temperature for 24 hours, and the pore-forming material was eluted (extracted) from the sheet. Then, the sheet was dried for 24 hours in a dryer set at 40 ° C. to obtain a sheet-like hydrophilic continuous porous body.

The hydrophilicity, the residue of the surfactant, the stickiness of the surface, and the hardness of each of the obtained Examples and Comparative Examples were measured and evaluated by the following methods. The results are shown in FIGS. 1 to 4. In addition, "NA" in FIG. 4 indicates that the porous body could not be molded and could not be measured and evaluated.

Regarding hydrophilicity, if one drop of water is dropped on the surface of the sheet of each example and each comparative example with a dropper and it is absorbed in the sheet within 3 seconds, it is judged that the hydrophilicity is high and "○" is absorbed. If it was not, it was judged that the hydrophilicity was low and it was marked with [x].

For the residue measurement of the surfactant, the sample was extracted with methanol in a Soxhlet extractor for 8 hours, the extract was concentrated to dryness with an evaporator, and further dried completely in a vacuum dryer, and the obtained dried product was subjected to Fourier transform. It is measured with an infrared spectrophotometer (FT-IR) (model name: IR6700, manufactured by JASCO Corporation) to determine whether or not it is a nonionic surfactant. The single reflection type ATR method is used.

Further, the dried product is broken again with methanol by an ultrasonic cleaner (model name: B-12, manufactured by Branson) and pulverized. The precipitate precipitated in methanol was subjected to a liquid chromatograph mass spectrometer (LC-TOFMS) (model name: maXisII, manufactured by Bruker Daltonics Co., Ltd.), and the carbon number and EO number were calculated from the obtained data to obtain the structure. Is identified, and it is determined whether or not it is a surfactant used for producing a hydrophilic continuous porous body. If the surfactant used in the production is confirmed, it is judged that the surfactant remains in the sample and it is set to "Yes". On the other hand, if the surfactant used in the production is not confirmed, the sample It was judged that no surfactant remained inside, and it was set to "None".

For the stickiness of the surface, spread yellow-green colored origami on the surface of the sample cut into 50 mm square, apply a load for 5 minutes using a weight of 3 kg, and then judge the discoloration of the colored paper and if there is no discoloration. It was judged to be non-sticky and set to "no", while when there was discoloration, it was judged to be sticky and set to "yes". The yellow-green colored origami had a lot of stains on the bleed of the surfactant.
The hardness was measured based on the Japan Rubber Association standard (SRIS / 0101).

In Examples 1 to 13, the hydrophilicity was "◯", the residual surfactant was "yes", and the surface stickiness was "no", and the hydrophilicity was good. Further, in Examples 1 to 4 and Examples 9 to 10 in which the volume% of polypropylene (homo PP) was 0.5 to 8 with respect to 20% by volume of the olefin elastomer, the hardness was C15 to C80. ..
On the other hand, the hardness of Example 5 and Example 6 in which the volume% of polypropylene (block PP or random PP) was 1 with respect to 20% by volume of the olefin elastomer, or Example 11 in which polypropylene was added as a master batch also had a hardness of C21. It was ~ C30.

Comparative Example 1 was an example in which polypropylene was not contained, the hydrophilicity was “x”, the residual surfactant was “absent”, and the surfactant did not remain, so that the hydrophilicity was low.

Comparative Example 2 is an example in which polyethylene is contained instead of polypropylene, and the hydrophilicity is “x”, the residual surfactant is “absent”, and the surfactant does not remain, so that the hydrophilicity is low. ..

Comparative Example 3 is an example in which the surfactant MB2, which is a mixture of the surfactant 1 and the surfactant 2 in a linear low-density polyethylene, is used and does not contain polypropylene, and the hydrophilicity is “x”, and the surfactant is The hydrophilicity was low because the residue was "absent" and no surfactant remained.

Reference Example A is an example of molding by adding a small amount of a surfactant 0.05 when the volume% of the porous body is as low as 11.05, and the hydrophilicity is “x” and the residual surfactant is “x”. No, the proportion of open cells was high, and the surfactant flowed out.

Reference Examples B and C are cases where the volume% of the continuous porous body (the total value of the volume% of the olefin elastomer and polypropylene) is 2.5 and 53.5, and both can form the porous body. There wasn't.

As described above, according to the present invention, it is possible to obtain a hydrophilic continuous porous body capable of maintaining good hydrophilicity for a long period of time.

Claims (5)

An olefin-based elastomer, polypropylene, a pore-forming material, and a nonionic surfactant are heated and kneaded to form the molded product, and the pore-forming material is eluted with a solvent from the obtained molded product to form the nonionic surfactant. a resulting Ru hydrophilizing methods hydrophilic continuous porous body sex surfactant remains,
The pore-forming material is a hydrophilic continuous porous body composed of a soluble inorganic substance and a soluble organic substance that can be dissolved in the same solvent, and the soluble inorganic substance and the soluble organic substance are mixed and used in combination . Hydrophilization method. The first aspect of claim 1, wherein the ratio of the soluble inorganic substance to the soluble organic substance is: soluble inorganic substance: soluble organic substance = 96.3: 3.7 to 11:89 (weight percentage wt%). A method for making a hydrophilic continuous porous body hydrophilic. The method for hydrophilizing a hydrophilic continuous porous body according to claim 1 or 2, wherein the polypropylene is composed of at least one of homopolypropylene, random polypropylene, and block polypropylene. The nonionic surfactant is any one of claims 1 to 3, wherein the nonionic surfactant is a polyoxyethylene alkyl ether having an alkyl carbon number of 15 to 40 and a degree of polymerization of oxyethylene of 2 to 8. The method for hydrophilizing a hydrophilic continuous porous body according to. A hydrophilic continuous porous body obtained by the hydrophilic method according to any one of claims 1 to 4, which is a continuous porous body composed of a mixed resin containing an olefin elastomer, polypropylene, and a nonionic surfactant. In addition, a hydrophilic continuous porous body characterized in that a nonionic surfactant remains.

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