JP6595774B2 - Composite material and method for producing the same - Google Patents

Description

  The present invention relates to a composite material and a method for producing the same, and more particularly to a composite material of an organic polymer and inorganic particles in which the concentration of inorganic particles in the surface layer is increased, and a method for producing the same. .

As a means to improve the added value of organic polymer materials such as adhesion, wear resistance, chargeability, water repellency, weather resistance and biocompatibility, different materials, especially inorganic materials, while maintaining the original polymer characteristics And the combination of the two, the surface modification of the material, or a combination of the two has been actively conducted. In order to increase the reforming effect in the composite of inorganic materials, it is important to increase the amount of inorganic materials as uniformly as possible.
On the other hand, surface modification methods for organic polymer materials include ultraviolet treatment, plasma treatment, corona discharge treatment, hydrogen peroxide treatment, and functional group imparting to the surface. In Patent Document 1, in order to improve the surface adhesion performance of the fluorine-based polymer, the surface roughness of the material is increased by using plasma etching, ion beam etching, or corona discharge treatment method, and then a silicon hydrophilic coating film is applied. It is disclosed to improve the hydrophilicity of the surface by forming. Non-Patent Document 1 discloses that a polypropylene material surface is irradiated with excimer light in the presence of water or perfluoropolyether to replace the OH group or CF ₃ group on the surface of the polypropylene material. Research that the surface is modified to be hydrophilic or hydrophobic, and thus the hydrophilic modification promotes protein adsorption, while the hydrophobic modification modifies protein adsorption. A paper is published.
Furthermore, as an example of technology combining the compounding with an inorganic material and the surface treatment, Patent Document 2 discloses hydrophilicity formed by graft polymerization with a hydrophilic monomer on a substrate plasma-treated with a hydrophobic polyolefin-based polymer. A method of laminating a hydroxyapatite (HA) layer in a stable state after coating with a layer of a conductive polymer is disclosed.

Japanese Patent No. 3274669 JP 2000-319010 A

Yuji Sato, Hiroyuki Anai, Masataka Murahara, the paper “Photochemical surface modification and protein adhesion of polypropylene using excimer lamp”, Tokai University Bulletin of Electronic Information Science, vol. 3, no. 2, 2003, pp. 41-44.

As a means of increasing the surface area of the inorganic material on the material surface by dispersing the inorganic material as uniformly as possible in the organic polymer, it is possible to make the inorganic material as fine as possible. However, the inorganic fine particles are likely to aggregate and difficult to uniformly disperse. . Furthermore, as the blending amount of the inorganic material increases, the original polymer characteristics cannot be maintained, such as the toughness of the organic polymer being impaired and becoming brittle.
On the other hand, in the case of ultraviolet treatment or plasma treatment for the purpose of modifying the surface of the organic polymer material itself, although the surface can be temporarily modified to hydrophilic, the hydrophilic layer on the surface decreases over time, There is a problem that it is difficult to maintain hydrophilicity and is not useful. Further, when hydrogen peroxide treatment is performed, there is a problem that almost no modification effect is observed. Therefore, the use of plasma treatment and excimer light as in Patent Documents 1 and 2 and Non-Patent Document 1 is limited to the use of pretreatment in which the surface of the organic polymer material is chemically modified.
Furthermore, even if surface modification by chemical modification of the organic polymer surface is possible via ultraviolet treatment or plasma treatment, these methods require complicated steps to achieve this, There are economic problems such as water washing, waste liquid treatment associated with washing, environmental problems and work problems, and the need for expensive equipment. In particular, in the case of organic polymer materials that are embedded in the body, especially in the case of medical device applications, the safety to the living body is important, so the substances that can be used to modify the surface of organic polymer materials as described above are extremely limited Is done.

  As described above, especially in the composite material of organic polymer and inorganic particles, when the surface of the composite material is to be modified so that the effectiveness of the inorganic particles is remarkably exhibited, there is a limit to the amount of inorganic particles added. In addition, there are various limitations on the surface modification by chemical modification through the above-described ultraviolet treatment or plasma treatment, and there is a problem that the performance of the original inorganic particles may not be exhibited by the modification.

  The present invention has been made under the circumstances described above, and the problem to be solved is easily maintained while maintaining the original characteristics of the organic polymer on the surface (surface layer portion) of the composite material of the organic polymer and the inorganic particles. An object of the present invention is to provide a composite material whose surface (surface layer portion) is modified so that the effect of inorganic particles is remarkably exhibited in a clean state, and to provide a manufacturing method thereof.

In order to solve the above problems, a composite material according to the present invention is a composite material having component A and component B, wherein component A is a base material and an organic polymer, and component B is a composite component and inorganic particles. The concentration of component B in the surface portion of the composite material is higher than the concentration of component B in the portion immediately below the surface layer portion of the composite material by irradiating the surface of the composite material using the action of ultraviolet light in the wavelength region of It is characterized by being.
Here, the term “particle” is not limited to a fine granular material, but is a conceptual term including a fine powdery material, a scale-like material, a crushed material, and the like.
In addition, “the concentration of component B” means that per certain volume,
Mass of component B / (mass of component B + mass of component A) × 100 (%)
That is.

  A typical composite material of the present invention is a composite material in which the organic polymer is a biodegradable and absorbable organic polymer, and the inorganic particles are bioceramic particles.

  The composite material manufacturing method according to the present invention is a composite material having a component A and a component B, wherein the component A is a base material and an organic polymer, and the component B is a composite component and inorganic particles. By irradiating ultraviolet rays in a specific wavelength region, the concentration of component B in the surface layer portion of the composite material is made higher than the concentration of component B in the portion immediately below the surface layer portion of the composite material.

  In the manufacturing method of this invention, it is preferable that the ultraviolet rays to irradiate are short wavelength ultraviolet rays of 250 nm or less.

  Like the composite material of the present invention, the concentration of the component B in the surface layer portion of the composite material is made higher than the concentration of the component B in the portion immediately below the surface layer portion of the composite material by ultraviolet irradiation to the surface. For example, as in the SEM (scanning electron microscope) image of FIG. 4, most of the component A (organic polymer) in the surface layer is decomposed and volatilized to form a concave portion, while the component B in the surface layer is formed. Component (B) (inorganic particles) remains as it is, and component B (inorganic particles) becomes an exposed or protruding irregular surface, and component A (organic polymer) decomposes and volatilizes and decreases by component B (inorganic particles). ) Concentration is high. Therefore, the surface activity and reactivity of component B (inorganic particles) that are increased in concentration and exposed or protrude from the surface layer portion are increased, and the effect of component B (inorganic particles) is remarkably exhibited.

  For example, component A (organic polymer) is hydrophobic, component B (inorganic particles) is hydrophilic, and the content of component B (inorganic particles) is less than that of component A (organic polymer) In the case of the composite material, the surface layer portion becomes more hydrophilic as the component A (organic polymer) of the surface layer is decomposed, volatilized and reduced by irradiation of the surface with ultraviolet rays, and the appropriate surface roughness Ra is obtained. The wettability of the surface of the composite material is greatly improved in combination with the increase in surface area due to the formation of the uneven surface. On the other hand, when it is desired to make the surface layer portion of the composite material hydrophobic, it is possible to add hydrophobic inorganic particles as component B (inorganic particles) to component A (organic polymer).

  As described above, the composite material of the present invention is sufficiently exposed or protruded by increasing the concentration of the component B (inorganic particles) in the surface layer even if the concentration of the component B (inorganic particles) of the composite material itself is somewhat low. The surface of the composite material without significantly changing the original properties (for example, mechanical properties) of the component A (organic polymer) by lowering the concentration of the component B (inorganic particles) of the composite material itself. Modification is possible. In addition, when component B (inorganic particles) is an expensive substance, it is possible to save material costs.

  In addition, as in the above-described representative example of the composite material of the present invention, the organic polymer is a biodegradable and absorbable organic polymer, and the inorganic particles are bioceramic particles. Decomposition and volatilization of the organic polymer increases the concentration of the bioceramic particles in the surface layer, and if the organic polymer is hydrophobic and the bioceramics are hydrophilic, the surface layer of the composite material becomes hydrophilic and forms an uneven surface. This significantly increases the surface area of the composite material and improves the wettability of the surface.For example, when this composite material is embedded in contact with bone in a living body, the surface of the composite material instantly gets wet with body fluids or blood. This makes it easy for blood proteins to settle, and the high-concentration bioceramic particles that are exposed or protrude from the surface layer exhibit sufficient osteoconductivity, thereby combining bone tissue. Bone regeneration is promoted is conducted to the charge.

  Next, when the surface of the composite material having component A (organic polymer) and component B (inorganic particles) is irradiated with ultraviolet rays as in the production method of the present invention, component A (organic polymer) in the surface layer portion of the composite material is Decomposition and volatilization forms a hollow portion, while surface layer component B (inorganic particles) remains as it is, forming an uneven surface with component B (inorganic particles) exposed or protruding, and component A (organic) The concentration of component B (inorganic particles) in the surface layer portion can be made higher than the concentration of component B (inorganic particles) in the portion immediately below the surface layer portion by the amount of decomposition and volatilization of the polymer).

  The irradiated ultraviolet rays are preferably short-wavelength ultraviolet rays of 250 nm or less. Since such short-wavelength ultraviolet rays have high photon energy, most of chemical bonds in the polymer molecules of the component A (organic polymer) in the surface layer portion are cut off. In addition, since the active oxygen generated by irradiation with short-wavelength ultraviolet rays and the cut polymer molecules can be reacted immediately and volatilized from the surface layer portion, the component B (inorganic particles) in the surface layer portion is highly concentrated. A composite material can be manufactured efficiently.

(A) is a schematic cross-sectional explanatory diagram before ultraviolet irradiation of a composite material in which inorganic particles of B component are contained in a dispersed state in an organic polymer of A component, and (b) is a diagram of the composite material after ultraviolet irradiation according to the present invention. It is a schematic cross section explanatory drawing. Scanning electron microscope (SEM) image of a composite material (HA / PLLA) composed of hydroxyapatite (HA) and poly-L-lactic acid (PLLA) according to an embodiment of the present invention before Xe excimer UV irradiation treatment (magnification 10,000) Times). It is a SEM image (magnification 10000 times) after Xe excimer UV irradiation processing (light quantity 900mJ / cm < ² >) of the composite material (HA / PLLA). It is a SEM image (magnification 10000 times) after Xe excimer UV irradiation processing (light quantity 2700 mJ / cm < ² >) of the composite material (HA / PLLA). It is a graph which shows the relationship between Ca density | concentration and HA density | concentration by EDX of a composite material (HA / PLLA). Xe excimer UV-irradiated composite material (HA / PLLA), Xe excimer UV-irradiated composite material (HA / PLLA), and Xe excimer UV-irradiated composite material (HA / PLLA) Is an absorption curve of Fourier transform infrared spectrophotometer (FT-IR) analysis. It is a SEM image (magnification 10,000 times) of the composite material (HA / PLLA) which irradiated metal halide light with the light quantity of 963 mJ / cm < ² >. It is a SEM image (magnification 10,000 times) of the composite material (HA / PLLA) irradiated with metal halide light with a light quantity of 6542 mJ / cm ² . It is a SEM image (magnification 10,000 times) of the composite material (HA / PLLA) which carried out the corona discharge process on the surface with the energy amount of 400 w * min / cm < ² >. It is a SEM image (magnification 10000 times) of the composite material (HA / PLLA) which carried out the corona discharge process on the surface with the energy amount of 2000 w * min / cm < ² >. It is a SEM image (magnification 10,000 times) of the composite material (HA / PLLA) which surface corona-discharge-treated the surface with the energy amount of 10000 w * min / cm < ² >. SEM images of untreated titanium oxide composite material consisting of (TiO ₂₎ and polyvinyl chloride _{(PVC) (TiO 2 / PVC} ). The Xe excimer UV is a SEM image of a composite material irradiation with light quantity of _{^{2138mJ / cm 2 (TiO 2 /}} PVC). The Xe excimer UV is a SEM image of a composite material irradiation with light quantity of _{^{3260mJ / cm 2 (TiO 2 /}} PVC). SEM images of a composite material consisting of untreated calcium silicate (CaSiO ₃₎ polyvinyl chloride _{(PVC) (CaSiO 3 / PVC} ) ( magnification 10,000 times). SEM images of 2138mJ / cm ² composite material in which the Xe excimer UV irradiation treatment in quantity (CaSiO ₃ / PVC). SEM images of 3260mJ / cm ² composite material in which the Xe excimer UV irradiation treatment in quantity (CaSiO ₃ / PVC).

  Hereinafter, with reference to the drawings, a composite material and a manufacturing method thereof according to the present invention will be described in detail.

  (A) of FIG. 1 is a schematic cross-sectional explanatory diagram before ultraviolet irradiation of a composite material in which inorganic particles of B component are contained in a dispersed state in an organic polymer of A component, and (b) is after ultraviolet irradiation according to the present invention. It is a schematic cross section explanatory drawing of this composite material.

  As shown in FIG. 1 (a), the composite material before ultraviolet irradiation is an organic polymer of component A (hereinafter simply referred to as organic polymer) in which the inorganic particles of component B (hereinafter simply referred to as inorganic particles) are matrix polymers. And the inorganic particles are not substantially exposed on the surface of the composite material (in other words, the surface of the organic polymer), the surface of the composite material has a very small surface roughness Ra. The surface is substantially smooth. In such a composite material, the concentration of inorganic particles is the same in both the surface layer portion and the lower portion (bulk portion excluding the surface layer portion) of the surface layer portion. In addition, the density | concentration of an inorganic particle is represented by the mass of the inorganic particle per fixed volume / (mass of an inorganic particle + mass of an organic polymer) x100 (%) as the said definition.

  When the surface of the composite material is irradiated with ultraviolet rays according to the manufacturing method of the present invention, as shown in FIG. 1 (b), the organic polymer in the surface layer portion of the composite material is decomposed and volatilized to form a hollow portion. On the other hand, since the inorganic particles in the surface layer remain as they are, and an uneven surface having an appropriate surface roughness Ra where the inorganic particles are exposed or protruded is formed, the inorganic particles in the surface layer portion are only decomposed and volatilized. Thus, the composite material of the present invention can be obtained in which the concentration of is higher than the concentration of inorganic particles in the portion immediately below the surface layer portion (bulk portion). As described above, the organic polymer in the surface layer is decomposed and volatilized by the ultraviolet irradiation. Most of the chemical bonds in the polymer molecule of the organic polymer in the surface layer due to the high photon energy of the ultraviolet ray, that is, in the polymer molecule. This is because a chemical bond having a bond energy smaller than the photon energy of ultraviolet rays is broken among the chemical bonds, and the active oxygen generated by the ultraviolet irradiation and the cut polymer molecules immediately react and volatilize.

  Therefore, the degree of increase in the concentration of inorganic particles in the surface layer of the composite material depends on the wavelength of ultraviolet rays to be irradiated (in other words, the amount of photon energy of ultraviolet rays) and the amount of irradiation light, and the shorter the wavelength of ultraviolet rays (in other words, The higher the photon energy) and the greater the amount of irradiation light, the higher the decomposition and volatilization amount of the organic polymer in the surface layer portion of the composite material, and the higher the concentration of inorganic particles in the surface layer.

Of course, it is possible to use an ultraviolet spectrum over a wide range of 200 to 450 nm emitted from a metal halide lamp, but this has a higher photon energy and a lower short wavelength ultraviolet output, so that the photon energy is higher than this. However, it is preferable to use short wavelength ultraviolet rays of 250 nm or less.
Examples of such short-wavelength ultraviolet rays of 250 nm or less include Xe excimer UV having a photon energy of 695 kJ / mol at a wavelength of 172 nm, and KrCl excimer UV having a photon energy of 539 kJ / mol at a wavelength of 222 nm. . In particular, the former Xe excimer UV, due to its high photon energy, most of the chemical bonds in the organic polymer (C-N triple bonds, C-C triple bonds, C-C triple bonds, C-C triple bonds being higher than 695 kJ / mol, C This is very preferable because the organic polymer can be decomposed and volatilized by cleaving the chemical bond other than the double bond between O and O.

  When the concentration of the inorganic particles in the composite material before the ultraviolet irradiation is uniform, the concentration of the inorganic particles in the surface layer portion after the ultraviolet irradiation is more uniform than the uniform concentration of the inorganic particles in the entire bulk portion including the portion immediately below the surface layer portion. However, when the concentration of inorganic particles in the composite material before UV irradiation is not uniform (for example, the concentration of inorganic particles changes from the front side to the back side of the composite material). In such a case, the concentration of the inorganic particles in the surface layer portion after ultraviolet irradiation is higher than the concentration of the inorganic particles in the portion immediately below the surface layer portion, in other words, the interface portion with the surface layer portion. .

  By the way, when corona discharge treatment is performed instead of ultraviolet irradiation, the concentration of inorganic particles in the surface layer portion can be increased slightly if the output is significantly increased as in the comparative example described later. Usefulness is difficult to recognize because it is less effective when it requires output.

  The organic polymer of the component A of the composite material is not particularly limited, and various known synthetic resins can be used. Typical examples are biodegradable and absorbable polymers (polylactic acid, polylactic acid copolymer (eg, lactic acid-glycolic acid copolymer)), polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyolefins, polyesters, polyurethanes, polycarbonates, polyacetals, polyamides, polybutylene terephthalates, polysulfones, polyether ether ketones, polyether imides, super engineering plastics represented by fluororesins, and the like.

  Also, the inorganic particles of the component B are not particularly limited, and for example, inorganic particles having various effects and functions such as bone conduction, medicinal effect, antibacterial, electrical conductivity, flame retardancy, and anti-slip can be used. Typical examples are bioceramic particles having osteoconductivity (hydroxyapatite, dicalcium phosphate, tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate, calcite, serabital, diopsite, etc.) Titanium oxide that imparts antibacterial, antifouling, and flame retardant effects, metal particles or carbon particles or fibers that impart electrical conductivity, calcium silicate that imparts fire resistance, and inorganic antibacterial agents of metal ions such as silver It is done.

  Next, main examples of the present invention will be described.

FIG. 2 is an SEM (scanning electron microscope) image of the composite material according to an embodiment of the present invention before Xe excimer UV irradiation treatment (magnification: 10,000 times), and FIG. 3 is an Xe excimer UV irradiation treatment (light quantity: 900 mJ) of the composite material. / Cm ² ) SEM image (10000 × magnification), FIG. 4 is a SEM image (10000 × magnification) after Xe excimer UV irradiation treatment (light quantity 2700 mJ / cm ² ) of the composite material.

The composite material of this example is composed of 60 parts by mass of biodegradable poly-L-lactic acid (PLLA) and 40 parts by mass of hydroxyapatite particles (HA) in a uniformly dispersed state (HA / PLLA). = 40/60), and the composite material before the Xe excimer UV irradiation treatment has a relatively flat surface with a small surface roughness Ra, as shown in the SEM image of FIG. However, when the surface of the composite material (HA / PLLA) is irradiated with Xe excimer UV (wavelength: 172 nm, 695 kJ / mol) at a light amount of 900 mJ / cm ² , as shown in the SEM image of FIG. The PLLA is decomposed and volatilized to form concave voids, while the HA particles in the surface layer remain as they are, resulting in a slightly rough surface with a surface roughness Ra. Further, Xe excimer UV is 2700 mJ / cm ² . When the irradiation is increased to the amount of light, the amount of decomposition and volatilization of PLLA on the surface layer portion increases, and as shown in the SEM image of FIG. 4, an uneven surface with a large surface roughness Ra is formed, and PLLA is decomposed and volatilized. Therefore, the composite material (HA / PLLA) in which the concentration of HA particles in the surface layer portion is higher than the concentration of HA particles in the portion immediately below the surface layer portion (bulk portion). .

The concentration of HA in the surface layer portion of the composite material (HA / PLLA) subjected to the above Xe excimer UV irradiation treatment (light quantity 900 mJ / cm ² , light quantity 2700 mJ / cm ² ) is obtained by the following method.
(1) First, four types of composite materials (HA / PLLA) having HA concentrations of 30 wt%, 40 wt%, 60 wt%, and 90 wt% are prepared, and each composite material is subjected to energy dispersive X-ray spectroscopy (EDX). A calibration curve is obtained by measuring the Ca concentration and plotting the relationship between the HA concentration and the Ca concentration, and a relational expression between the Ca concentration and the HA concentration is created. The relationship between the Ca concentration and the HA concentration is as shown in Table 1 below. The relationship between the Ca concentration and the HA concentration is plotted on the Y axis and the HA axis as the X axis, and the calibration curve is obtained in the graph shown in FIG. is there. The relational expression created based on this calibration curve is y = 0.1935x + 14.612.
It is.

(2) Next, the surface of the composite material (HA / PLLA) having an HA concentration of 40 wt% is irradiated with Xe excimer UV while gradually increasing the irradiation light amount as shown in Table 2 below. The Ca concentration by EDX of the composite material subjected to the excimer UV irradiation treatment is measured. Then, by substituting these Ca concentrations into y in the above relational expression, the HA concentration x in the surface layer portion of each composite material was obtained, and as shown in Table 2 below.

As shown in Table 2, the HA concentration in the surface layer portion of the composite material (HA / PLLA) in FIG. 2 that has not been subjected to the Xe excimer UV irradiation treatment is 37.6 wt%, and the Xe excimer UV irradiation is performed at a light amount of 900 mJ / cm ^2. The HA concentration in the surface layer portion of the treated composite material (HA / PLLA) in FIG. 3 is 56.9 wt%, and the surface layer of the composite material (HA / PLLA) in FIG. 4 treated with Xe excimer UV irradiation at a light amount of 2700 mJ / cm ² . It can be seen that the HA concentration in the part is 72.0 wt%. From Table 2, it can be seen that as the amount of irradiation light increases, the HA concentration in the surface layer portion of the composite material increases and becomes higher.
Since the maximum X-ray incident depth of EDX is about 10 μm, there is a possibility that the HA concentration in the extremely shallow part of the surface layer is higher than the quantitative value.

  Further, the HA concentration in the surface layer portion of the composite material (HA / PLLA) subjected to the Xe excimer UV irradiation treatment with the irradiation light amount not described in Table 2 is measured by measuring the Ca concentration by EDX of the composite material. Needless to say, it can be easily obtained by substituting x into y in the above relational expression and calculating x (HA concentration).

Next, the surface of the composite material (HA / PLLA) having an HA concentration of 40 wt% is irradiated with Xe excimer UV while increasing the irradiation light intensity stepwise as shown in Table 3 below, and Fourier transform is performed for each composite material. infrared spectrophotometer (FT-IR) analyzes, and the peak height of the HA-derived 1032Cm ^-1, with examining peak heights of PLLA-derived 1756cm ^-1, both peak ratio (peak height from HA / Peak height derived from PLLA). The results are shown in Table 3 below.

Looking at the table 3, Xe as the irradiation light amount of excimer UV increases, peaks both peak ratio of the peak and HA-derived 1032cm ^-1 of PLLA-derived 1756cm ^-1 (HA peak derived height / PLLA from Peak height) is increasing. Therefore, it can be seen from this increase in the peak ratio that the HA concentration in the surface layer portion increases as the amount of Xe excimer UV irradiation increases.

FIG. 6 shows a composite material (HA / PLLA) not subjected to Xe excimer UV irradiation treatment with an HA concentration of 40 wt%, and a composite material (HA / PLLA) subjected to Xe excimer UV irradiation treatment with an irradiation light amount of 1800 mJ / cm ^2. FT-IR for a composite material (HA / PLLA) that has been subjected to Xe excimer UV irradiation treatment at an irradiation light amount of 1800 mJ / cm ² and then sterilized with EOG (ethylene oxide gas) for the purpose of application to an implantable bone fixation material It is an absorption curve of analysis.

When the upper absorption curve (of the untreated composite material) in FIG. 6 is compared with the middle absorption curve (of the composite material subjected to the Xe excimer UV irradiation treatment), the peak height derived from HA hardly changes. On the other hand, the peak height derived from PLLA is attenuated to about 1/3 of the peak height derived from PLLA before the Xe excimer UV irradiation treatment. It can be seen that the majority of the PLLA decomposes and volatilizes, whereas HA remains and is exposed as it is, and the HA concentration in the surface layer is increased. Furthermore, since no peak at a new wavelength is observed in the absorption curve in the middle stage, it can be seen that there is no byproduct due to the Xe excimer UV irradiation treatment, and that PLLA is purely decomposed and volatilized.
Then, when comparing the absorption curve in the middle stage (for the composite material subjected to Xe excimer UV irradiation treatment) and the absorption curve in the lower stage (for the composite material subjected to EOG sterilization after the Xe excimer UV irradiation treatment), the absorption curve in the lower stage is The peak derived from the by-product by EOG sterilization is not seen, and the lower absorption curve is a curve that almost overlaps with the absorption curve of the composite material not subjected to EOG sterilization in the middle. From this, it can be seen that EOG sterilization of the composite material does not adversely affect the Xe excimer UV irradiation treatment.

The composite material (HA / PLLA) of this example is 40% by weight of hydrophilic HA particles and 60% by weight of hydrophobic PLLA. Therefore, the composite material as a whole is hydrophobic. However, by irradiation with Xe excimer UV (wavelength 172 nm, 695 kJ / mol), the hydrophobic PLLA on the surface layer of the composite material is decomposed, volatilized and reduced, and the hydrophilic HA particles remain as they are or are exposed or protruded. Therefore, the surface of the composite material becomes hydrophilic.
In order to support this, Xe excimer UV is irradiated on the surface of the composite material while increasing the amount of irradiation light stepwise as shown in Table 4 below, and the contact angle of each composite material surface with water is measured by a contact angle meter ( Kyowa Interface Science Co., Ltd., FACE contact angle meter CA-A type). The results are shown in Table 4 below.
Further, KrCl excimer UV (wavelength 222 nm, 539 kJ / mol) is irradiated onto the surface of the composite material while increasing the irradiation light amount stepwise as shown in Table 5 below, and the contact angle of each composite material surface with water Was measured. The results are shown in Table 5 below.

From Table 4 above, as the irradiation light amount of Xe excimer UV increases, the contact angle with water on the surface of the composite material (HA / PLLA) decreases and becomes hydrophilic, and Xe excimer UV irradiation treatment is performed at an irradiation light amount of 2700 mJ / cm ^2. It can be seen that the composite material with a reduced contact angle is reduced to 6 ° and exhibits super hydrophilicity.
Further, from Table 5 above, when KrCl excimer UV irradiation treatment is performed, the photon energy of KrCl excimer UV is smaller than that of Xe excimer UV, but the effect is small. However, as the irradiation light quantity increases, the surface water of the composite material increases. When the contact angle with the surface of the composite material decreases and the surface layer portion of the composite material becomes hydrophilic, the contact angle decreases to 67 ° when the irradiation light quantity increases to 5580 mJ / cm ² .

In addition, in order to investigate the effect of EOG sterilization on the hydrophilicity of the composite material (HA / PLLA), the surface of the composite material that was degassed for 10 days after EOG sterilization treatment with Xe excimer UV irradiation at a light intensity of 2700 mJ / cm ² And the contact angles of the composite material which was degassed and stored for one week in a moisture-proof package in the air, those stored for three months, and those stored for six months were measured. The results are shown in Table 6 below. Furthermore, as a comparative example, the contact angle of the surface of the composite material which was degassed for 10 days after XE excimer UV irradiation treatment at a light quantity of 2700 mJ / cm ² on a PLLA-only material not complexed with HA, and this composite The contact angle of the material stored for 1 week was measured. The results are also shown in Table 6 below.

The contact angle of the surface of the composite material (HA / PLLA) not subjected to EOG sterilization is 6 ° and is superhydrophilic. However, the composite material subjected to EOG sterilization (degassed for 10 days) is also The contact angle of 2 ± 1 ° is super hydrophilic, and composite materials stored for 1 week, 3 months, and 6 months also have contact angles of 2 ± 1 °, 2 ± 0 °, It exhibits a super hydrophilicity of 10 ± 3 °. From this, it can be seen that the surface of the composite material subjected to the excimer UV treatment has a property that is not affected by the decrease in hydrophilicity due to the EOG gas sterilization treatment.
On the other hand, the PLLA-only material that has not been combined with HA exhibits hydrophilicity by reducing the contact angle of the surface by the Xe excimer UV irradiation treatment, but it remains at a decrease of 30 ± 1 ° with the same amount of irradiation as the composite material. It can also be seen that the contact angle increases to 55 ± 2 ° by EOG sterilization treatment, and further increases to 68 ± 5 ° for the PLLA-only material stored for one week, and tends to return to hydrophobic properties.
Radicals such as OH and COOH are formed on the surface of the excimer UV-treated organic polymer, which greatly contributes to the hydrophilicity of the surface. On the other hand, these radicals decrease over time, and it is difficult to maintain hydrophilicity for a long time. The results of the above-mentioned PLLA-only material support this, and organic polymers alone have hydrophilization and hydrophilic long-lasting limits even with excimer UV treatment. However, the surface contact angle of the Xe excimer UV-irradiated composite material (HA / PLLA) maintained superhydrophilicity for 6 months only because this hydrophilic effect is due to the formation of radicals such as OH and COOH. Rather, it can be said that the effect is manifested by increasing the concentration of essentially hydrophilic HA on the surface of the composite material (HA / PLLA).

In the composite material of this example, the composite material (HA / PLLA) having an HA concentration of 40 wt% is subjected to Xe excimer UV irradiation treatment to decompose and volatilize PLLA in the surface layer portion, thereby forming a hollow portion. Since the particles remain exposed or protruded as they are, the surface thereof is an uneven surface. In order to investigate the relationship between the irradiation light amount of the Xe excimer UV and the surface roughness Ra of the composite material, as shown in Table 7 below, the irradiation light amount is increased stepwise to change the Xe excimer UV to an HA concentration of 40 wt. % Of the composite material (HA / PLLA) was irradiated, and the surface roughness Ra of each composite material was measured based on JIS B 0601. The results are shown in Table 7 below.

  From Table 7, it can be seen that as the amount of Xe excimer UV irradiation increases, the amount of decomposition and volatilization of PLLA in the surface layer portion of the composite material increases and the surface roughness Ra increases.

In addition, in order to investigate the presence or absence of deterioration of the composite material due to Xe excimer UV irradiation, Xe excimer UV is applied to both sides of the 1 mm thick composite plate (HA / PLLA) with an HA concentration of 40 wt% at a light quantity of 2700 mJ / cm ² . And the bending strength and viscosity average molecular weight of the composite plate were measured.
As a result, the composite plate after the Xe excimer UV irradiation has a bending strength of about 180 MPa and a viscosity average molecular weight of about 180,000, and almost the same as the bending strength and viscosity average molecular weight of the composite plate before the Xe excimer UV irradiation treatment. I did not.
From this, it can be seen that in the range where Xe excimer UV is irradiated with a light amount of 2700 mJ / cm ² , the composite material is not deteriorated and the original mechanical properties of HA / PLLA are maintained.

About the Xe excimer UV irradiation-treated composite material (HA / PLLA, HA concentration 40 wt%), the Xe excimer UV irradiation light amount, the contact angle (°) with water on the material surface, and the peak by FT-IR analysis The ratio (1032 cm ⁻¹ / 1756 cm ⁻¹ ), the Ca concentration by EDX, and the HA concentration of the surface layer portion converted based on the Ca concentration are listed in Table 8 below.

  As described above, the composite material (HA / PLLA) that has been subjected to the Xe excimer UV irradiation treatment does not require chemical modification, and is a material only of HA and PLLA that has already been proven in implantable medical devices. Yes, the biodegradable and absorbable PLLA (hydrophobic) in the surface layer is decomposed and volatilized, so that the concentration of HA particles (hydrophilic) in the surface layer becomes high and the surface layer of the composite material becomes hydrophilic without generating by-products. At the same time, the surface area of the composite material is greatly increased by the formation of the uneven surface having an appropriate surface roughness Ra, and the wettability of the surface is improved. Further, the surface property of the composite material can be adjusted by the amount of irradiation light without causing deterioration of the composite material. Therefore, for example, when this composite material is embedded in contact with bone in a living body, high concentration HA particles exposed or protruded on the surface layer sufficiently exhibit osteoconductivity, whereby bone tissue becomes composite material. Since conduction and bone regeneration are promoted, it is extremely useful as a bone implant material or the like to be implanted in a living body.

FIG. 7 is an SEM image (10,000 × magnification) of the surface of a composite material obtained by irradiating metal halide light (wavelength 200 to 450 nm) with a light amount of 963 mJ / cm ^{2 on} the surface of the composite material (HA / PLLA) having an HA concentration of 40 wt%. FIG. 8 is an SEM image (10,000 × magnification) of a composite material obtained by irradiating metal halide light with a light amount of 6542 mJ / cm ² . The SEM image of the surface of the composite material (HA / PLLA) that is not subjected to the metal halide light irradiation treatment is the same as the SEM image of FIG.
The composite material of FIG. 8 has some HA particles exposed on its surface, and the HA concentration in the surface layer portion seems to be slightly high, but the composite material of FIG. It seems that the HA concentration is hardly increased.

The composite material shown in FIGS. 7 and 8 subjected to the metal halide light irradiation treatment, and the surface water measured in the same manner as described above for the composite material (HA / PLLA) subjected to the metal halide light irradiation treatment with an irradiation light amount of 1280 mJ / cm ² Contact angle (°), peak ratio (1032 cm ⁻¹ / 1756 cm ⁻¹ ) by FT-IR analysis, Ca concentration by EDX, HA concentration converted based on it, and the presence or absence of the effect of increasing HA concentration Are summarized in Table 9 below.

Table 9 shows that metal halide light has a small output of short wavelength ultraviolet rays with a large photon energy. Therefore, when the amount of irradiation light is small (when 1280 mJ / cm ² or less), the hydrophilicity of the composite material also increases the PLLA of the surface layer portion. The decomposition and volatilization of the surface layer and the increase in the HA concentration in the surface layer are hardly observed, and it can be seen that there is no substantial effect. However, when the irradiation light quantity increases to 6542 mJ / cm ² , the HA concentration in the surface layer portion increases to 56.84 wt%, and an effect equivalent to that obtained when Xe excimer UV is irradiated with a light quantity of 900 mJ / cm ² can be obtained. I understand. From this, it can be seen that the ultraviolet rays to be irradiated are extremely effective when the photon energy is 250 nm or less, preferably 200 nm or less.

As a comparative example, an SEM image (magnification 10,000 times) of a composite material (HA / PLLA, HA concentration 40 wt%) whose surface was subjected to corona discharge treatment with an energy amount of 400 w · min / cm ² is shown in FIG. 9 and 2000 w · min. FIG. 10 shows an SEM image (a magnification of 10,000 times) of the composite material whose surface was corona discharge treated with an energy amount of / cm ² , and an SEM of the composite material whose surface was corona discharge treated with an energy amount of 10,000 w · min / cm ^2. Images (magnification 10,000 times) are listed in FIG.
Then, the composite material that does not these composite materials and corona discharge treatment, contact angle with water was measured in the same manner as the as (°), the peak ratio by FT-IR analysis ^{(1032cm -1} / ^1756cm -1 ), Ca concentration by EDX, HA concentration converted based on it, and the presence or absence of the effect of increasing HA concentration are listed in Table 10 below.

Referring to FIG. 11, the surface of the composite material whose surface is subjected to corona discharge treatment with an energy amount of 10000 w · min / cm ² has many fine concave portions formed therein, and the HA particles have a small amount of corona discharge energy. Compared to the surface of the composite material of FIG. 10, the HA concentration seems to be slightly higher.
Also, from Table 10 above, the contact angle of the composite material is reduced to nearly 50 ° by corona discharge treatment, which makes it considerably hydrophilic. However, the HA concentration in the surface layer portion of the composite material is 10000 w · Even at min / cm ² , it is only about 7 wt% higher than the HA concentration of the untreated composite material. Therefore, it can be said that the corona discharge treatment is not useful as a means for increasing the concentration of HA in the surface layer of the composite material.

Next, as another embodiment of the present invention, a composite material (TiO ₂ / PVC, TiO ₂ concentration 14.6 wt%) in which titanium oxide particles are contained in a vinyl chloride resin will be described.
FIG. 12 is an SEM image of an untreated composite material (TiO ₂ / PVC), FIG. 13 is an SEM image of a composite material (TiO ₂ / PVC) irradiated with Xe excimer UV at a light intensity of 2138 mJ / cm ² , and FIG. the Xe excimer UV is a SEM image of a composite material irradiation with light quantity of _{^{3260mJ / cm 2 (TiO 2 /}} PVC).

The composite material (TiO ₂ / PVC) of this example has a relatively flat surface with a small surface roughness Ra as shown in the SEM image of FIG. 12 before the Xe excimer UV irradiation treatment. However, when the surface is irradiated with Xe excimer UV (wavelength 172 nm, 695 kJ / mol) at a light intensity of 2138 mJ / cm ² , the PVC in the surface layer of the composite material decomposes and volatilizes as shown in the SEM image of FIG. While the hollow portion is formed, the TiO ₂ particles in the surface layer portion remain as they are, and are exposed somewhat, resulting in an uneven surface having a slightly large surface roughness Ra. When the Xe excimer UV is irradiated to increase the light amount to 3260 mJ / cm ² , the decomposition and volatilization amount of PVC in the surface layer portion increases, while the TiO ₂ particles in the surface layer portion are exposed or protruded, and the SEM image in FIG. As shown in FIG. 3, the surface becomes a rough surface with a large surface roughness Ra, and the TiO ₂ concentration in the surface layer portion is increased by the amount of decomposition and volatilization of PVC. However, since the composite material itself has a low TiO ₂ concentration of 14.6 wt%, the increase in the concentration of TiO _{2 in} the surface layer is not so remarkable.

As shown in Table 11 below, the surface of this composite material (TiO ₂ / PVC) is irradiated with Xe excimer UV while gradually increasing the amount of irradiation light, and each of the composite materials is irradiated using the contact angle meter. The contact angle of the surface with water was measured. The results are shown in Table 11 below.

As shown in Table 11, the contact angle of the composite material (TiO ₂ / PVC) not subjected to the Xe excimer UV irradiation treatment is as large as 82.5 ° and is hydrophobic, but the irradiation light amount of the Xe excimer UV is It can be seen that the contact angle decreases as the increase increases, and the hydrophilicity of the composite material subjected to the Xe excimer UV irradiation treatment with a light amount of 3260 mJ / cm ² is significantly reduced by decreasing the contact angle to 24 °.
The composite material _(TiO 2 / PVC), because the composite material concentration of TiO ₂ itself is as low as 14.6 wt%, TiO ₂ in the surface portion of when the Xe excimer UV irradiation treatment in light quantity of 3260mJ / cm ² The increase in concentration is about 1%, but it should be noted that, as shown in Table 11, the contact angle is greatly reduced and a significant wettability improvement effect is obtained.

Titanium oxide is active when it receives light (ultraviolet light) energy, and exhibits a strong oxidizing action, and thus has antibacterial, antifouling and anticlouding effects. Since the above-mentioned composite material (TiO ₂ / PVC) subjected to the Xe excimer UV irradiation treatment has TiO ₂ particles exposed or protruded on the surface layer portion, this composite material is suitable for applications such as a sheet having these effects. is there.

Next, as another embodiment of the present invention, a composite material (CaSiO ₃ / PVC, CaSiO ₃ concentration 32 wt%) in which calcium silicate is contained in a vinyl chloride resin will be described.
FIG. 15 is an SEM image of an untreated composite material (CaSiO ₃ / PVC), FIG. 16 is an SEM image of a composite material (CaSiO ₃ / PVC) irradiated with Xe excimer UV at a light intensity of 2138 mJ / cm ² , and FIG. the Xe excimer UV is a SEM image of a composite material irradiation with light quantity of _{^{3260mJ / cm 2 (CaSiO 3 /}} PVC).

The composite material (CaSiO ₃ / PVC) of this example has a relatively flat surface on which CaSiO ₃ is not exposed as shown in the SEM image of FIG. 15 before the Xe excimer UV irradiation treatment. However, when the surface is irradiated with Xe excimer UV (wavelength 172 nm, 695 kJ / mol) at a light intensity of 2138 mJ / cm ² , the PVC in the surface layer of the composite material decomposes and volatilizes as shown in the SEM image of FIG. While a small concave portion is formed, the CaSiO ₃ particles in the surface layer portion are somewhat exposed, resulting in an uneven surface with a relatively small surface roughness Ra. When the Xe excimer UV is irradiated to increase the light amount to 3260 mJ / cm ² , the decomposition and volatilization amount of PVC in the surface layer portion increases and the hollow portion increases, while the CaSiO ₃ particles in the surface layer portion are exposed or protruded. As shown in the SEM image of FIG. 17, the composite material (CaSiO ₃ / PVC) has a concavo-convex surface with a large surface roughness Ra, and the CaSiO ₃ concentration in the surface layer is increased by the amount of decomposition and volatilization of PVC. )

This Xe excimer UV-irradiated composite material (CaSiO ₃ / PVC) is suitable for uses such as a flame retardant member because CaSiO ₃ particles are exposed to or protrude from the surface layer portion and have a fire resistance that suppresses combustion.

Claims (8)

A composite material comprising biodegradable and absorbable organic polymer and bioceramic particles,
A composite material comprising the biodegradable and absorbable organic polymer and the bioceramic particles dispersed in the biodegradable and absorbable organic polymer is prepared, and the composite material is irradiated with ultraviolet rays to form the composite material . A composite material characterized in that the concentration of the bioceramic particles in the ultraviolet irradiation part is higher than that before the ultraviolet irradiation. 2. The composite material according to claim 1, wherein the surface roughness of the composite material at an ultraviolet irradiation portion is greater than that before the ultraviolet irradiation. The composite material according to claim 1, wherein the bioceramic particles are uniformly dispersed in the biodegradable and absorbable organic polymer in the composite material.   The bioceramics constituting the bioceramic particles are hydroxyapatite, dicalcium phosphate, tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate, calcite, serabital, or diopsite. Item 4. The composite material according to any one of Items 1 to 3.   The composite material according to any one of claims 1 to 4, wherein the biodegradable and absorbable organic polymer is polylactic acid or a polylactic acid copolymer.   The composite material according to any one of claims 1 to 4, wherein the biodegradable and absorbable organic polymer is a lactic acid-glycolic acid copolymer. A step of preparing a composite material by dispersing bioceramic particles in a biodegradable and absorbable organic polymer;
A step of increasing the concentration of the bioceramics particles in the ultraviolet action irradiation portion of the composite material than before the ultraviolet irradiation by irradiating ultraviolet light to the composite material,
A method for producing a composite material comprising bioceramic particles and a biodegradable and absorbable organic polymer. The method for producing a composite material according to claim 7, wherein the ultraviolet rays are short-wavelength ultraviolet rays having a wavelength of 250 nm or less.