JP2007512405A - Absorbent polymer material - Google Patents

Abstract

  A hygroscopic polymeric material comprising a combination of a thermoplastic material and an adsorbent is disclosed. The thermoplastic material is selected such that when the adsorbent is added to the thermoplastic material in the molten state and then shaped as a product, the adsorbent moves toward the surface of the hygroscopic polymer material to form a moving region; The adsorbent is characterized by being present at a higher concentration relative to its surface than to the interior of the polymer material.

Description

Related applications

  The present invention claims priority in connection with application number PCT / FR03 / 03465, filed Nov. 24, 2003.

  The present invention relates to a thermoplastic product having an adsorbent incorporated therein. More preferably, the present invention relates to a product formed from a thermoplastic material, the plastic material having an adsorbent concentrated with respect to the surface direction of the product, wherein preferably the adsorbent concentration gradient is Exists. The present invention further mixes the thermoplastic material with the adsorbent and concentrates the hygroscopic polymer product so that there is a concentration gradient of the adsorbent, preferably concentrated on the surface of the product, preferably absorbing moisture. The present invention relates to a method for producing an adsorbent polymer material formed as a product, comprising a forming step.

  Many moisture sensitive products need to be transported and stored under as little moisture as possible. For example, drugs and diagnostic test strips often lose some of their effectiveness after prolonged exposure to moisture, but are preferably loaded and stored in an environment with no moisture. The container for holding such a product is formed of a moisture-impermeable material such as a known thermoplastic that prevents external moisture from entering. However, such intrusion of moisture into the container is unavoidable through diffusion or opening and closing of the container, so that the product is exposed to moisture. In the case of pharmaceuticals, end users often open plastic containers repeatedly to use just one dose, and the remaining dose will be exposed to air containing undesirable moisture. Accordingly, such a container is preferably provided with means for absorbing moisture, and the moisture sensitive product is placed inside after it has been put into the container.

  In the case of another item, such as a food or another organic product, if it is placed inside a container or sealed package before it is substantially released, and if the package is substantially moisture impermeable, Stay in close proximity to the product. In many cases, this released moisture will cause substantial damage to the product that has released the moisture. In this case, some drying means is preferably included in the package to absorb the released moisture and maintain a relatively dry environment.

  In addition, for other items such as electronic components, a substantially moisture-free environment is required during loading and storage to provide optimal performance. These items are typically loaded in moisture impervious containers, but the presence of initially trapped moisture, or long-term moisture leakage, affects the performance of these products. Again, drying means are preferably included in the loading container that absorbs moisture but does not affect other parts.

  In order to absorb such excess moisture and to protect the contained product, a dry material is introduced inside the container. Since these desiccants are usually formed in powder or granule form, they need to be included in some way to avoid product contamination. As a pre-treatment for introducing the desiccant into such a container, the desiccant is put inside using bags and parcels formed from moisture-permeable material, porous plastic containers, dry tablets and breathable plastic cartridges. Including. These containers are problematic, however, and if any damage occurs, a large amount of desiccant is dissipated in the containers. Also, these desiccant-containing containers release some of the dust generated from the filled desiccant and further adversely affect the product to be protected from moisture. Another solution is to form a separate compartment in the container to hold the desiccant (eg, a tube stopper filled with desiccant or a side compartment inside the tube). It typically limits the mutual contact between moisture and desiccant and reduces the adsorption rate. Furthermore, there is a risk that the desiccant may be released from the side compartments into the main compartment due to breakage.

  That is, it is necessary to introduce the adsorbent into a plastic container or another product while preventing the adsorbent from dissipating and potential contact with the moisture sensitive product. One way to achieve this goal is to mix the adsorbent directly into the plastic structure so that the desiccant cannot be released. However, as a problem peculiar to this structure, once it is mixed inside the plastic as an adsorbent, contact with external moisture is extremely limited.

  Accordingly, as a primary object of the present invention, an adsorbent-incorporated polymer product is provided that allows moisture and adsorbent to be contacted in an effective amount, preferably and without the use of wicking fibers. is there.

  Additional objects and advantages of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned from embodiments of the invention. The objects and advantages of the invention will be realized and attained by means of the elements or combinations particularly pointed out in the appended claims.

  Both the foregoing summary and the following detailed description are exemplary, and are merely exemplary and the invention is not limited thereto.

Summary of the Invention

  In the context of the present invention, the thermoplastic material is produced with an adsorbent entrained therein. During the manufacturing process of the product produced from this composition, the thermoplastic material is in a dissolved or non-solid state, and the adsorbent inside the thermoplastic material can move toward the surface of the product, so the adsorbent was produced. It is concentrated with a gradient towards the surface of the product.

  The accompanying drawings constitute a part of and constitute a part of this specification, and illustrate an embodiment of the invention together with the description and explain the principles of the invention.

  The present invention provides a highly hygroscopic polymer material comprising a thermoplastic material mixed with at least one adsorbent. The hygroscopic polymer material (hygroscopic polymer product) shows a separation of a certain amount of constituents, i.e. the concentration of the adsorbent is much higher at the surface of the product produced from this absorbent polymer material than inside it. Further, the concentration gradient of the adsorbent toward the surface is shown. As used herein, “separation” defines differences in concentration gradients and does not require 100% separation of components into different phases. Similarly, “layered” as used herein means a significant change in the concentration gradient, where the product is layered, with a solid layer composed of one component and a second layer composed of another component. There is no need. “Gradient” means that the concentration of any component in the absorbent polymer material varies with the distance from the surface of the product made from the absorbent polymer material.

  A “thermoplastic material” as used herein is defined as a polymeric material that exhibits thermoplastic properties. A thermoplastic material is a polymer consisting of a single monomer; a copolymer consisting of two or more monomers; a mixture of two or more polymers consisting of a single monomer; a mixture of two or more copolymers; one or more consisting of a single monomer Composed of a mixture of a polymer and one or more copolymers, and in preferred embodiments the thermoplastic material is a mixture of two or more copolymers, or a mixture of at least one polymer and at least one copolymer derived from a single monomer. The components of this mixture are composed of those having a common monomer unit. As a non-limiting example, the thermoplastic material is produced from a blend of linear low density polyethylene (LLDPE), low density polyethylene (LDPE) and ethylene vinyl acetate (EVA) copolymer, each component being composed of ethylene units.

  Non-limiting examples of single monomer derived polymers include: polystyrene; polyolefin (polyethylene, polypropylene); polyacrylate, polymethacrylic acid: polyamide, polyimide, polyester, polybutylene, terephthalate, polycarbonate, polyethersulfone, and polyvinyl chloride. Non-limiting examples of copolymers include: styrene-butadiene rubber (SBR); styrene-ethylene-butadiene-styrene copolymer (SEBS); butyl rubber; ethylene-propylene rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); Vinyl acetate copolymers (EVA); ethylene-acrylate or butadiene-acrylonitrile; maleic anhydride modified polymers and copolymers; polyether-polyamide copolymers; and grafted copolymers. Unless otherwise specified, the adsorbents used herein are defined as materials that have the ability to absorb moisture, or to absorb moisture, or vice versa, to remove moisture from ambient ambient air. (Although technically different in reaction mechanism, for the purposes of the present invention, the terms absorption and adsorption are used interchangeably). Non-limiting examples of adsorbents include: desiccants such as silica gel, zeolite, dry clay, molecular sieve, activated carbon, alkaline earth oxide.

  The highly hygroscopic polymer material is solid and its shape can form a variety of products suitable for promoting moisture adsorption. For example, the product takes the form of a small cylinder or cube so that it can be placed in a container that contains only a low moisture content. Further examples include container linings or packaged products comprising the absorbent polymer material of the present invention.

  As an example, a pharmaceutical container or a diagnostic piece and a titration plate are manufactured by forming an outer shell from a water-impermeable plastic material, polyethylene, polypropylene, or the like. In one preferred manufacturing method, a complete or partial liner is formed from the absorbent polymer material and added to the inside of the container. In another preferred embodiment, the liner is formed inside the container in a double injection mold or is formed separately from the container and then inserted. Another suitable method of forming the absorbent polymer is extrusion, i.e., the preferred method of forming the liner is to separate liner extrusion and container molding and assemble the two parts later. In yet another preferred embodiment, the absorbent polymer material is also used to form an entire product (eg, a container or flake), ie, the entire product is composed of the hygroscopic polymer material described herein. The Note that there is no outer shell for this embodiment. The product of the present invention has a high absorption rate and good absorption kinetics due to the presence of the adsorbent in the moving region (near the surface), and also has a (moisture) barrier function due to the lack of adsorbent in the inner region.

  The hygroscopic polymeric material can be used in all applications where moisture absorption is desired. Non-limiting examples include moisture sensitive articles such as food, diagnostics, pharmaceuticals, semiconductor technology, or general use packaging that is used as an enclosed space required over a period of low humidity. This includes, but is not limited to, primary and secondary packaging. As a further aspect, it is used directly on sticks used in wafer manufacture. Another application of the hygroscopic polymer material is applied to odor adsorption.

  In use, the composition according to the invention further comprises a suitable amount; organic or inorganic additives, preferably up to 10% by weight, optimally up to 5% by weight, which additives are used in the plastics field. Examples of commonly used fillers, reinforcing agents, plasticizers, stabilizers, dyes, slip agents, wetting agents, dispersants, non-flocculating agents, antistatic agents, processing agents, foaming agents, and pigments.

  On the other hand, the absorbent polymer material preferably does not contain wicking fibers because the fibers burn or dissolve during the manufacturing process. Since the multilayer structure of the composition of the present invention increases hygroscopicity, fibers that act as moisture cores are unnecessary.

Surprisingly, the product produced from the absorbent polymer composition that shows a buildup of adsorbent with a gradient towards the surface in the “moving zone” is a structure containing the same concentration of adsorbent throughout the product. It has been found that there is a significant advantage in hygroscopicity compared to structures (monolithic structures) and structures containing only a desiccant on the surface. Structures with a desiccant only on the surface tend to limit the overall hygroscopic capacity due to the relatively small amount of adsorbent that is contained or incorporated on the surface, while the products related to the present invention are only on the surface. Not only does the overall structure of the product be filled with an effective amount of adsorbent, it exhibits high capacity. Monolithic structures with the same concentration of adsorbent throughout the product tend to have a relatively low rate of moisture absorption due to limited contact between the (relatively less) adsorbent particles on or near the surface and ambient moisture. is there. In contrast, the product of the present invention contains a relatively large amount of adsorbent on or near the surface, so it can react faster with ambient moisture compared to a monolithic structure. In addition, adsorbents with suitable gradients in the moving region provide an advantageous transmission chain that quickly transports the material absorbed by the adsorbent, such as moisture, away from the surface. Thus, there is no excess moisture that remains transiently on the surface due to transport that is delayed toward the inside of the product. In contrast, monolithic structures, structures that have adsorbents only on the surface, and multilayer structures that combine adjacent or bonded layers containing different concentrations of adsorbents are more delayed in moisture transport as they move away from the surface Due to the tendency, there is an excess of moisture on the surface, which can have deleterious consequences for moisture sensitive articles to be protected. For the preferred embodiment of the present invention, the sorbent gradient is a constant gradient, and more preferably the sorbent concentration is continuously reduced from the surface to the inside of the layer, as shown for example in FIG. I am letting. Thus, the present invention overcomes the shortcomings of both structures and monolithic structures having adsorbent only on the surface by combining a high adsorption capacity and a relatively high initial adsorption rate. Furthermore, the materials according to the present invention can be configured to exhibit higher or lower initial adsorption velocities while having the exact same chemical composition and the same thickness, which is the accumulation of adsorbent within the “migration area”. Adjust by increasing or decreasing the amount and / or the thickness of the “moving zone” itself.

The hygroscopic polymer material is preferably:
From about 20% to about 85% by weight of one or more thermoplastic materials; and from about 15% to about 80% by weight of at least one adsorbent.

  This composition is produced such that the adsorbent has a concentration gradient within the moving region near the surface of the polymer composition. In a preferred embodiment, the layer of the composition can be distinguished by the concentration of adsorbent at the surface, i.e. the surface layer is rich in adsorbent and the inner layer is clearly discerned by the same adsorbent being depleted. Make possible layers.

The surface layer of the product (typically on both sides of the product, such as flakes and tubes) produced from the absorbent polymer material usually forms a relatively clear "moving zone" where the adsorbent "moves" . The maximum concentration of adsorbent in a certain volume unit within this moving region is 2 to 10 times higher, preferably 2 to 6 times higher than the concentration inside the product or in the central layer. The concentration of the adsorbent inside this moving region is preferably shown with a gradient towards the surface. The concentration of adsorbent anywhere in the product and the extent of adsorbent migration are determined by infrared microanalysis. For this purpose, the synthesized peak intensity of the characteristic IR absorption band of the adsorbent (and if necessary the copolymer) is a function of depth δ, measured using a transversal microtomic cut of appropriate thickness (eg 30 μm). Is done. Each value is normalized by comparison with the integrated adsorption intensity of the polymer component at the respective depth δ, and further a function D of depth from the surface for the values 0 to d (d is the total thickness of the part). Plotted as (δ) and C (δ). The dry amount contained in the predetermined depth interval (Δδ = δ ₂ −δ ₁ ) is ∫D (δ) dδ (limit values δ ₁ , δ ₂ ) and ∫D (δ) dδ (limit values 0, d ). This “moving region” is defined by the depth from the surface of the place where the accumulation of drying force reaches a peak (δ ₁ ) and begins to increase further (δ _r ). The amount of dryness contained in these regions is the index of ∫D (δ) dδ (limit values 0, δ ₁ ) and ∫D (δ) dδ (limit values 0, d) and the first movement region. By calculating the indices of 上述 D (δ) dδ (limit value δ _r , d) and ∫D (δ) dδ (limit value 0, d) for the two regions, it can be calculated as described above. . All (simple) parts generated with respect to the present invention have been shown so far with two moving regions, except that parts generated with respect to the present invention may contain only one or more moving regions. Can not. Comparing the amount of adsorbent present in the inner layer of the composition with the amount present in the migration region (in a constant volume unit), at least about 50% of the amount of adsorbent material present in the migration region, preferably at least about It is reduced by 65% and optimally at least about 85%.

  The thickness of this moving region will vary depending on many factors, such as the composition of the thermoplastic material, if a mixture is used, the ratio of polymer to copolymer material occupying this thermoplastic material, the concentration of adsorbent used, When this mixture is utilized, it includes the amount of non-common monomers present in the copolymer and polymer mixture and the parameters set in forming the product from the absorbent polymer material. Furthermore, it has been surprisingly found that the higher the proportion of copolymer present, the thicker the migration zone. Nevertheless, surprisingly, the thickness of the migration region from the surface of the hygroscopic polymeric material according to the product manufacturing process is usually about 1 to about 100 microns, preferably about 10 to about 80 microns. And was optimally found to be about 20 to about 60 microns. The overall thickness of the moving zone varies and is likely to change particularly in very thick products, but surprisingly the thickness of the moving zone is relatively independent of the overall thickness of the material and is usually about 1 to about It was found to be 100 microns.

  Surprisingly, it has also been found that the amount of adsorbent accumulated in a certain volume unit within the moving zone is considerably larger than the amount accumulated in a certain volume unit of the entire inner layer of the product. Surprisingly, the proportion of adsorbent present in the migration region of the product produced from the absorbent polymer material is at least about 2% of the total adsorbent present in the product, preferably at least about 4%, and optimal Has been found to be at least 6%, with a maximum amount of about 70% or less of the total amount of adsorbent, preferably 50% or less and optimally 40% or less.

  In order to achieve this layer separation, it has been found preferable to use a mixture of at least one polymer derived from a single monomer and at least one copolymer as the thermoplastic component. Surprisingly, it has been discovered that the higher the proportion of copolymer used, the greater the amount of adsorbent present in the migration zone. Furthermore, the higher the proportion of copolymer, the greater the thickness of the transfer zone. Preferably, the two polymeric materials are interchangeable because the copolymer contains monomers of a single monomer component of the polymer. If two or more copolymers are mixed to form a thermoplastic material, each preferably should contain at least one common monomer. In such a suitably mixed thermoplastic composition, one of the components of the thermoplastic mixture is enriched with the adsorbent at the surface, while the other component is enriched towards the center of the product. It was discovered that there was a tendency.

  Generally, the absorbent polymer material is produced by a compounding method.

  In one suitable method of making the absorbent polymer material, the polymer and copolymer (if necessary) are mixed by dry mixing without the use of a solvent or without melting the polymer material. This mixed polymer and copolymer (if necessary) are then introduced simultaneously (but separately) with the adsorbent into the first region of the compounding device. The first zone of the mixer is preferably maintained at a temperature below the melting point of all components, preferably about 50 ° C. This mixture is then introduced into the next region of the compounding device where the polymer and copolymer materials are melted and further mixed with the adsorbent. In a preferred embodiment, the mixed material is then extruded through a mold into a cooling water batch and cut into granules.

  Usually, in the second step, the absorbent polymer material is formed into a product. The molding of the product is performed on the thermoplastic product by known methods, such as extrusion, injection molding, blow molding, etc., which transform the absorbent polymer material into an essentially non-solid state, Preferably it involves dissolving the thermoplastic material in a liquid state. Should not be combined with any particular theory, the adsorbent moves towards the surface of the product formed only when it is essentially in a non-solid state and during the molding process (injection molding, extrusion molding, etc.) Is possible. Therefore, care must be taken when handling the article so that the adsorbent and the thermoplastic material remain essentially non-solid and are sufficiently favorably separated by the transfer described herein. Also, it should not be combined with any particular theory, and in embodiments where the thermoplastic material is comprised of one or more polymers or copolymers, the adsorbent is more attracted and separated toward one of the polymer materials. In the meantime, it will move towards the surface with the polymer material.

  The thickness of the moving zone and the amount of adsorbent that accumulates inside it is further influenced by the parameters set during molding of the product. As noted above, migration of the adsorbent is possible as long as the absorbent polymer material is essentially in the non-solid state. That is, the molding method (injection molding, blow molding, extrusion molding), the temperature of the absorbent polymer material when molded, the temperature control of the tool or mold during molding, the flow characteristics of the material, the flow rate during molding, the molding Parameters such as product shape and cycle time are important in determining the amount of adsorbent transfer time during molding (transfer time). Transfer time is defined as the product molding time while the adsorbent can be transferred because the absorbent polymer material is essentially in a non-solid state.

In fact, a product extrusion process with a shear level of less than about 100 s ⁻¹ has a more pronounced separation phenomenon than is carried out by injection molding. Also, it should not be combined with any particular theory, which probably means that the extrusion process provides a fairly long travel time by providing the material more directly oriented at a constant flow rate in a single direction. It is because it enables. In injection molding that causes strong turbulence, the material flows in a certain direction at a shear rate of 1,000 to 10,000 s ⁻¹ , but then contacts the wall of the injection mold to cause backflow and liquid. Partial remixing of the composition occurs. The degree of remixing is also affected by the shape of the shaped product. Furthermore, in injection molding, the walls of the injection mold tend to cool the injected outer layers of thermoplastic material rapidly, thus strongly preventing the adsorbent from moving into these outer layers.

  Those skilled in the art can adjust the above parameters by routine experimentation, and by optimizing these parameters for each individual product with respect to travel time, the desired travel zone thickness and the adsorbent within it. Accumulation can be achieved.

  The invention will be clarified by the following non-limiting examples.

  In order to demonstrate the phenomenon of adsorbent migration to the surface, a composition was prepared consisting of 50 wt% thermoplastic material and 50 wt% desiccant (molecular sieve). The thermoplastic material was composed of 22% by weight linear low density polyethylene (LLDPE), 62% by weight low density polyethylene (LDPE) and 16% by weight ethylene vinyl acetate (EVA) copolymer.

  This mixture was formed into flakes having various thicknesses by extrusion molding and injection molding. This slice can then be sliced into 30 μm sections and analyzed every 30 μm until the concentration of each component reaches its surface and its center.

  Referring to FIGS. 1 and 2, FIG. 1 shows an infrared spectral analysis for the surface of an extruded specimen produced in accordance with the present invention having a total thickness of 850 μm. This extrusion process was carried out at about 200 ° C. and a pressure of about 110 bar. In FIG. 1, peaks for polyethylene, EVA and molecular sieve were identified. FIG. 2 shows similar data taken from the center of an extruded flake, similarly produced according to the present invention. As can be seen from the two IR analyses, the peak amplitudes of EVA and molecular sieve, ie the concentration of EVA and molecular sieve, are significantly higher at the surface than at the center of the flakes. Conversely, the polyethylene peak, or polyethylene concentration, is higher at the center of the extruded flakes.

  FIG. 3 shows the result of IR spectrum analysis in which the thickness of the entire extruded slice is 0.40 mm. As shown in FIG. 3, the concentrations of EVA and molecular sieve were very high on the two surfaces of the flakes and then leveled off at a depth of 35 μm in the flakes. The concentrations of EVA and molecular sieve were then kept almost constant at a depth of 35 μm to the center of the flake.

  The area of composition until the concentration of EVA and molecular sieve rises to its peak is defined as the moving region thickness. In the above example, the moving zone thickness of the extruded flake is 35 μm. Surprisingly, it has been observed that the overall thickness of the flakes has no substantial effect on the moving zone thickness. For example, an extruded flake having the same composition as that defined in Example 1 is expected to have a moving zone thickness of approximately 35 μm regardless of the thickness of the flake.

  This phenomenon is shown in Table 1 below, comparing flakes with various thicknesses formed by both extrusion and injection molding.

  In the above table, the thickness of the moving region with respect to the injection molded part is independent of the thickness of the molded part. However, the concentration of the molecular sieve accumulated on the surface is a function of the thickness, that is, the larger the thickness of the injection molded part, the higher the numerical value of the molecular sieve. It should not be combined with any particular theory, the finding is that the thicker the injection molded part, the longer the cooling period (moving time) until the molten component solidifies, thus accumulating on the surface of the molecular sieve. Further, it can be explained from the fact that the time for forming the layer structure becomes longer.

  The moisture absorption of an injection molded sample having a thickness of 1170 μm and an extruded sample having a thickness of 1140 μm was tested at 25 ° C. and 80 RH (relative humidity), and is shown in FIG. As referenced, the extruded part reacts with moisture faster than the injection molded part. It takes 26 days for the extrusion molding part and 64 days for the injection molding part to reach saturation. This result coincides with the movement region of 55 μm in the extrusion molding part and the movement region of 24 μm in the injection molding part.

  FIG. 4 shows an optical microscope image in a cross-sectional view of a 1.2 mm extruded flake as the composition of this example. The concentration of molecular sieve (adsorbent) on the surface of the flakes is clearly indicated by its dark color.

  The moisture absorption of the flakes was measured to be 10.5% by weight at 25 ° C. and 80% rh.

  The dryness to the surface of the different polymer compositions is shown visually in this example. An absorbent polymer composition consisting of 65 wt% thermoplastic material and 35 wt% adsorbent (silica gel) was prepared. The thermoplastic material was composed of a mixture of 92.3% by weight polystyrene and 7.7% by weight styrene-ethylene-butadiene-styrene copolymer. The suction cartridge was formed by injection molding in the same manner as shown in FIG. Such a cartridge is suitable for installation inside a container for moisture sensitive products such as pharmaceuticals. FIG. 6 is a photograph of a cross-sectional view of the cartridge taken with an optical microscope. The density of the molecular sieve is clearly indicated by the dark gray area of the photograph towards the surface of the cartridge.

  In this example, it is shown that an absorbent polymer composition with very high absorption capacity can be produced according to the present invention. An absorbent polymer composition was prepared consisting of 30 wt% thermoplastic material, 70 wt% adsorbent (molecular sieve). The thermoplastic material was composed of 76.7% by weight ethylene-methyl acrylate copolymer and 23.3% by weight ethylene-acrylic ester-maleic anhydride copolymer.

  A 1.3 mm thick flake was extruded from this composition. As shown in FIG. 7, the moisture absorption was measured to be 14.6% by weight at 30 ° C. and 60% rh.

  An absorbent polymer composition was prepared consisting of 50 wt% thermoplastic material, 50 wt% adsorbent (molecular sieve). The thermoplastic material was composed of a mixture of 92.3% by weight polystyrene and 7.7% by weight styrene-ethylene-butadiene-styrene copolymer.

  This composition comprises injection molded articles (0.9 mm, 1.1 mm, 1.5 mm thick plates, 1.08 mm thick tubes) and extrusion molded articles (0.5 mm, 0.6 mm thick flakes, 1 .. 2 mm thick tube).

Table 2 shows the results of measurement of the accumulation and migration region of the adsorbent in the composition of Example 4. The amount of molecular sieve was determined using the integral intensities of the IR absorption peak at 1652 ^-1 polystyrene / SEBS to the integral intensities of the IR absorption band between 2821~3112cm ^-1.

  With respect to Table 2, a typical moving region extends between approximately 20-40 μm from the surface of the article to the interior. The intensity ratio of the molecular sieve: (polystyrene / SEBS) IR peak decreases to between approximately 50% and 20% of the surface value within the moving region. This indicates that the molecular sieve concentration per unit volume around the surface of each member is 2 to 5 times higher than the central part of the material.

  Table 3 below shows the amount of dryness accumulated in the transfer area as a percentage of the total amount of dryness.

  These results show that a large amount of adsorbent accumulates on or around the surface of the member manufactured according to the present invention.

  The same compound as described in Example 1 was prepared. This compound was extruded into a tube approximately 1 mm thick after mixing with various amounts of ammonium bicarbonate (0%, 0.5%, 0.8%) as a blowing agent.

  A foaming agent is defined as a material that is mixed with the above compound and then subjected to extrusion, injection molding or another method of forming the article, during which the compound is at least partially removed as a gas or vapor. The

  From these results, it can be seen that the addition of the blowing agent to the compound does not affect the range of the moving bed when forming the article. However, the amount of molecular sieve that accumulates in this layer increases with increasing amount of blowing agent.

  Other embodiments of the invention will be apparent to those skilled in the art from the description of the invention and examples provided herein. The specification and examples merely show typical examples, and the scope of the true invention is indicated by the claims.

Figure 1 shows an infrared microanalysis (FT-IR) on the surface of an extruded flake of the produced absorbent polymer material with a thickness of 0.85 mm for Example 1; (For illustration and examples, the zeolite is treated with a molecular sieve). For Example 1, the FT-IR of the center of the produced extruded flakes of adsorbed product with a thickness of 0.85 mm is shown. 2 shows the FT-IR of the entire extruded flake of the adsorbent material of Example 1. 1 shows an optical microscope cross-sectional view of an extruded flake of the product produced according to Example 1, using a molecular sieve as an adsorbent and showing a concentration gradient of the molecular sieve. FIG. 3 shows a drawing of an adsorbent cartridge produced with respect to Example 2. FIG. Fig. 6 shows a photograph of the cut surface of the cartridge of Fig. 5, showing the concentration gradient of the adsorbent taken with an optical microscope. 2 shows a curve of the hygroscopic capacity of the material described in Example 3. The time-dependent comparison result which test | inspected the hygroscopicity of the injection molded sample of thickness 1170micrometer and the extrusion molding sample of thickness 1140micrometer at 25 degreeC is shown. Both samples are produced by the method of Example 1.

Claims (23)

  A hygroscopic polymer product comprising a mixture of thermoplastic material and adsorbent, the product comprising at least one moving region and an inner region on the surface of the product, the maximum concentration of adsorbent within the moving region being the inner region A hygroscopic polymer product, characterized in that it is at least twice the maximum concentration of the internal adsorbent.   The hygroscopic polymer product according to claim 1, wherein the moving region exhibits a gradient in the concentration of the adsorbent.   The thermoplastic material is a polymer composed of a single monomer, a copolymer composed of two or more monomers, a mixture of two or more polymers composed of a single monomer, a mixture of two or more copolymers, and at least one polymer composed of a single monomer 2. The hygroscopic polymer product according to claim 1, wherein the hygroscopic polymer product is selected from the group consisting of a mixture with at least one copolymer.   The hygroscopic polymer product of claim 1, wherein the thermoplastic material is a mixture of at least one polymer and at least one copolymer of a single monomer.   The hygroscopic polymer product of claim 1, wherein at least one copolymer of the thermoplastic material includes monomer units in common with the polymer.   2. A hygroscopic polymer product according to claim 1 wherein the thermoplastic material is a mixture of two copolymers containing common monomer units.   The moisture-absorbing polymer product of claim 1, wherein the transfer zone is comprised of from about 1 to about 100 microns in product thickness.   The hygroscopic polymer product of claim 1 wherein the concentration of adsorbent within the moving region is about 2 to about 6 times the concentration of adsorbent within the inner region of the product.   The hygroscopic polymer product of claim 1 wherein the thickness of the transfer zone is from about 10 to about 80 microns.   Thermoplastic material is polystyrene; polyolefin (polyethylene, polypropylene); polyacrylate, polymethacrylic acid: polyimide, polycarbonate, polyethersulfone polyamide, polyester; and polyvinyl chloride; styrene-butadiene rubber (SBR); styrene-ethylene-butadiene- Styrene copolymer (SEBS); butyl rubber; ethylene-propylene rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); ethylene-vinyl acetate copolymer (EVA); ethylene-acrylate or butadiene-acrylonitrile; maleic anhydride modified The hygroscopic polymer product of claim 1 selected from the group consisting of polymers and copolymers; and grafted copolymers.   The hygroscopic polymer product of claim 1, wherein the adsorbent is selected from the group consisting of silica gel, zeolite, dry clay, molecular sieve, activated carbon, alkaline earth oxide and mixtures thereof.   The hygroscopic polymer product of claim 1 wherein wicking fibers are not added to the thermoplastic material and the adsorbent.   A hygroscopic polymer product comprising a thermoplastic material and an adsorbent, the product comprising at least one moving region on the surface of the product and an inner region of the product, the moving region having a thickness of about 1 to about 100 Hygroscopic polymer product characterized by being micron.   The thermoplastic material is a polymer composed of a single monomer, a copolymer composed of two or more monomers, a mixture of two or more polymers composed of a single monomer, a mixture of two or more copolymers, and at least one polymer composed of a single monomer 14. A hygroscopic polymer product according to claim 13 selected from the group consisting of a mixture with at least one copolymer.   14. The hygroscopic polymer product of claim 13, wherein the thermoplastic material is a mixture of at least one polymer comprising at least one monomer and at least one copolymer.   16. The hygroscopic polymer product according to claim 15, wherein the at least one copolymer comprises monomer units in common with the polymer.   14. A hygroscopic polymer product according to claim 13, wherein the thermoplastic material is a mixture of two copolymers containing common monomer units.   14. The hygroscopic polymer product of claim 13, wherein the moving zone has a thickness of about 10 to about 80 microns.   14. The hygroscopic polymer product of claim 13, wherein the concentration of adsorbent within the moving region is from about 2 to about 6 times the concentration of adsorbent within the inner region of the product.   Thermoplastic material is polystyrene; polyolefin (polyethylene, polypropylene); polyacrylate, polymethacrylic acid: polyimide, polycarbonate, polyethersulfone polyamide, polyester; and polyvinyl chloride; styrene-butadiene rubber (SBR); styrene-ethylene-butadiene- Styrene copolymer (SEBS); butyl rubber; ethylene-propylene rubber (EPR); ethylene-propylene-diene monomer rubber (EPDM); ethylene-vinyl acetate copolymer (EVA); ethylene-acrylate or butadiene-acrylonitrile; maleic anhydride modified 14. The hygroscopic polymer product of claim 13, selected from the group consisting of polymers and copolymers; and grafted copolymers. 14. The hygroscopic polymer product according to claim 13, wherein the adsorbent is selected from the group consisting of silica gel, zeolite, dry clay, molecular sieve activated carbon, alkaline earth oxide and mixtures thereof. In a method for producing a hygroscopic polymer product,
This is a method in which a thermoplastic material is produced, the molten thermoplastic material is mixed with an adsorbent, and then the thermoplastic material and adsorbent mixture are formed into a hygroscopic polymer product using an extrusion molding method. The product consists of a moving area on the surface of the product and an inner area away from the moving area of the product, and the concentration of the adsorbent inside the moving area is at least about twice the concentration of the adsorbent inside the inner area. A process for producing a hygroscopic polymer product, characterized in that In a method for producing a hygroscopic polymer product,
This is a method of forming a thermoplastic material, mixing the molten thermoplastic material with an adsorbent, and then molding the thermoplastic material and adsorbent mixture into a hygroscopic polymer product using an injection molding method. The product consists of a moving area on the surface of the product and an inner area away from the moving area of the product, and the concentration of the adsorbent inside the moving area is at least about twice the concentration of the adsorbent inside the inner area. A process for producing a hygroscopic polymer product, characterized in that