WO2006001313A1

WO2006001313A1 - Gel, process for producing the same, water-absorbing resin, lubricating material, and substrate for cell culture

Info

Publication number: WO2006001313A1
Application number: PCT/JP2005/011469
Authority: WO
Inventors: Jian Ping Gong; Yoshihito Osada; Hiroyuki Tsukeshiba
Original assignee: National University Corporation Hokkaido University; Medical & Biological Laboratories Co., Ltd
Priority date: 2004-06-25
Filing date: 2005-06-22
Publication date: 2006-01-05
Also published as: JPWO2006001313A1; JP5059407B2

Abstract

A technique by which the strength of a gel can be improved without impairing excellent properties of the gel, such as high flexibility and high water retention; and various uses of the gel. In the gel, a crosslinked polymer constitutes the basic skeleton of the gel and forms a rigid network structure having scatteringly distributed vacant parts which are extremely sparse parts in the network, while an uncrosslinked polymer localizes in these vacant parts and is physically entangled at end parts thereof with the network structure of the crosslinked polymer while retaining flexibility. In the gel having a semiinterpenetrating network structure, crack propagation over a long distance cannot occur as long as an extremely large external force exceeding stresses diffusible by the uncrosslinked polymer is not applied. Even when a fracture occurs microscopically, it does not become a macroscopic fracture under these conditions. This gel never break unless an extraordinarily large external force is applied, because the critical value leading to a macroscopic fracture is extremely high.

Description

Gel, production method thereof, water-absorbent resin, lubricant and cell culture substrate

[0001] The present invention relates to a gel having a semi-interpenetrating network structure in which another polymer is entangled with a network structure composed of a crosslinked polymer, a method for producing the gel, and a water-absorbent resin and a lubricant using the gel. The present invention relates to a material and a cell culture substrate.

Background art

[0002] Gels, which are two-phase colloidal systems of liquid and solid, have excellent properties such as high flexibility and high water retention, and various applications for industrial use have been made using these properties. It is being considered. For example, Patent Document 1 discloses a low-friction material obtained by mixing a linear polymer with a gel or graft polymerization.

[0003] However, since the conventional gel has a remarkably low mechanical strength, its intended use is easily restricted due to insufficient strength and durability.

[0004] Accordingly, various techniques for increasing the mechanical strength of the gel have been studied and developed (for example, Patent Documents 2 to 7 and Non-Patent Documents 1 to 4). Among these, for example, Patent Document 2 discloses that a second polymer is formed by polymerizing and crosslinking a monomer in a network structure having the strength of the first crosslinked polymer, thereby forming the first crosslinked polymer and the second polymer. Describes a technique for producing a hide-mouthed gel having an interpenetrating network structure or semi-interpenetrating network structure in which and are intertwined with each other. The “interpenetrating network structure” refers to a network structure in which other network structures are entangled with the base network structure, and the “semi-interpenetrating network structure” refers to the base network structure. A linear polymer is entangled to indicate a network structure.

Patent Document 1: JP 2002-212452

Patent Document 2: Pamphlet of International Publication No. 03Z093337

Patent Document 3: Japanese Patent Laid-Open No. 2004-91724

Patent Document 4: Japanese Unexamined Patent Application Publication No. 2002-053762

Patent Document 5: Japanese Unexamined Patent Application Publication No. 2002-053629

Patent Document 6: Japanese Unexamined Patent Publication No. 57-130543 Patent Document 7: JP-A-58-36630

特 S Dry Literature 1: J.P.Gong, Yoshinori Katsuyama, Takayuki Kurokawa, YoshihitoOsada, Double-Network Hydrogel with Extremely High Mechanical Strengtn, Advanced Materials, 15, 1155-1158 (2003)

Special Article 2: H. Haraguchi, T. Takeshita, "Nanocomposite Hydrogels: A Unique Organics—Inorganic Network Structure with Extraordinary Mechanical, Optical, and Swelling / De—swelling Properties", Advanced Materials, 14, 1120—1123 (2002) Non-specialty literary literature 3: Y. Okumura, Kohzolto, "The Polyrotaxane Gel: A Topological Gel by Figure— of— Eight Cross— links”, 13, 485-487 (2001)

Non-patent document 4: Long Zhao, Hiroshi Mitomo, Naotsugu Nagasawa, Fumio Yoshn, Tami kazu Kume, "Radiation synthesis and characteristic of the hydrogels based on carbo xymethylated chitin derivatives, Carbohydrate Polymers, 51, 169-175 (2003) Disclosure

Problems to be solved by the invention

[0005] However, as a result of continuing intensive studies to further improve the strength of the gel by developing the technology disclosed in Patent Document 2, the present inventors have found that Patent Documents 2-7 and Knowledge different from the development concept of the technology disclosed in Patent Documents 1 to 4 was obtained. That is, for example, in the technique disclosed in Patent Document 2 or Non-Patent Document 1, the most important factors for improving the strength of the gel are the molar ratio of the second monomer to the first crosslinked polymer and the degree of crosslinking of the second polymer. In particular, in the technique disclosed in Patent Document 2, the second polymer has a very slight cross-linked structure. Specifically, the degree of cross-linking of the second polymer is 0.001 mol% or more. Although there is an optimum condition for increasing the strength of the gel, there is a limit.

[0006] An object of the present invention is to provide a technique capable of dramatically improving the strength of a gel without impairing excellent properties such as high flexibility and high water retention property of the gel, and further to the gel To provide various uses.

Means for solving the problem

[0007] The gel according to the present invention has a semi-interpenetrating network structure in which a non-crosslinked polymer invades a network structure composed of a crosslinked polymer and is physically entangled. In this case, the degree of swelling is 5 or more, the weight content of the good solvent is 80% or more, and the fracture energy is 700 jZm ² or more and 2000 jZm ² or less.

[0008] That is, the second polymer that is not a crosslinked polymer is linear and has a high molecular weight without having any crosslinked structure. It was found that the strength of the gel is specifically improved only when the second polymer adopts a non-crosslinked polymer rather than a crosslinked structure. The invention's effect

[0009] According to the present invention, a non-crosslinked polymer having high flexibility satisfying a predetermined condition enters and is physically entangled in a rigid network made of a crosslinked polymer and in which cavities are scattered. It is possible to provide a gel with mechanical strength and durability comparable to or better than tissue.

Brief Description of Drawings

[0010] FIG. 1 is a diagram schematically showing a semi-interpenetrating network structure of a gel according to the present invention.

[Fig. 2] A diagram schematically showing a cavity of a network structure made of a crosslinked polymer in a semi-interpenetrating network structure

[Fig. 3] The state of deformation of the semi-interpenetrating network structure at the crack tip of the gel according to the present invention and the transient network due to physical entanglement regardless of chemical crosslinking in the velocity region where the non-crosslinked polymer exists. A diagram that schematically shows how it forms a resistance to crack progression by forming

[Fig. 4] Schematic diagram showing the external force velocity region where a transient network is formed in a non-crosslinked polymer in a concentrated solution state.

[Fig. 5] The fracture energy of the gel according to the present invention and the weight average molecular weight M of the non-crosslinked polymer

Diagram showing the correlation of w

BEST MODE FOR CARRYING OUT THE INVENTION

[0011] The essence of the present invention is that a gel having a semi-interpenetrating network structure in which a non-crosslinked polymer in the form of a random coil having a size satisfying the cavity is entangled with a network structure in which cavities having a crosslinked polymer force are scattered. Is to form. The size of the random coil depends on the molecular weight of the unbridged polymer.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. When evaluating the gel according to the present invention, “compressive strength” is used as an index indicating the mechanical strength, and “breaking energy” is used as an index indicating the fracture mechanical strength. “Compressive strength” is the value obtained by dividing the stress required to break the gel by the initial area, and “Fracture energy” is the work used for steady progress of the gel divided by the fracture area. The value, i.e., the energy required to form a fracture surface. Therefore, as an index indicating the superiority or inferiority of the gel, it is more appropriate to use the fracture energy rather than the compressive strength, taking into account the characteristics of the gel that the deformation rate until fracture is extremely large (Y. Tanaka, K. rukao, Y. Miyamoto, Fracture energy of gels, ie European Physical Journal, 3, 395-401 (2000)).

[0014] FIG. 1 schematically shows a semi-interpenetrating network structure of the gel according to the present invention. The cross-linked polymer that forms the basic skeleton of the gel forms a rigid network structure in which cavities, which are extremely sparse parts of the network, are scattered, while the non-cross-linked polymer is concentrated in these cavities, While maintaining flexibility, it is physically entangled with the network structure of the crosslinked polymer at its end.

[0015] Here, "physically entangled" means that two or more discontinuous linear objects are not in a coupled state by a shared bond or the like, but the spatial position is constrained. It means a state that cannot be unwound if there is at least one location where the obtained positional relationship exists and both or one of them is not physically destroyed or deformed. However, in the case of something that is microscopic and cannot be seen in the first place, use an electron micrograph, etc. There should be at least one close point. However, the physical entanglement between the polymers present in the solution cannot be confirmed with an optical microscope or the like. Since a physical entanglement is formed in the part, it can only be suggested by a dynamic light scattering device or the like. In the following, the structure in which the non-crosslinked polymer is entangled with the void-containing crosslinked polymer is sometimes referred to as a double network (DN).

[0016] A network structure in which cavities having a cross-linked polymer force are scattered is formed, for example, by radical copolymerization of a bull monomer and a dibul monomer. Bull monomers and dibules Since monomers are different in reactivity in radical polymerization, when they are copolymerized, a microgel is formed in the early stage of the reaction, and when it grows, the microgel crosslinks to form a non-uniform network structure. (See Erik Geissler, "Dynamic light scattering from polymer gels, Chapter 11 ^th , 471-511, Edited by WYNBrown, 'Dynamic Light Scattering -The Method and Some Applications-" CLARENDON PRESS, OXFORD (1993)). The network structure of the cross-linked polymer formed in this way is spatially non-uniform because the difference in mesh density increases as the degree of swelling increases when a large amount of solvent is absorbed and equilibrium swelling is reached. (Hidemitsu Furukawa, Kazuyuki Horie, "Swelling- induced modulation of static and dynamic fluctuations in polyacrylamide gels observe d by scanning microscopic light scattering, Physical Review E, 68, 031406 (2003), Mitsuhiro Shibayama," Spatial inhomogeneity and dynamic fluctuations of polymer ge Is ", Macromol. Chem. Phys., 199, 1-30 (1998)). Also, compare the network structure composed of the electrolyte cross-linked polymer and the network structure composed of the non-electrolyte cross-linked polymer. If the degree of cross-linking is the same, then the equilibrium swelling degree and the non-uniformity of the network are significantly greater in the former than in the latter, so the network structure composed of the crosslinked polymer of the electrolyte has a network structure. Considered very sparse portion or cavity is scattered reliably. In addition, the measurement data by the dynamic light scattering method, supports this idea.

On the other hand, in the present invention, “non-crosslinked polymer” refers to a polymer having a degree of crosslinking of less than 0.001 mol%, preferably a polymer that is not crosslinked at all, and the degree of crosslinking is a polymerization of a non-crosslinked polymer. The quantity power of the crosslinking agent added at the time is also calculated. A polymer having a low degree of cross-linking is soluble in a solvent in a sol state that does not form a gel, and tends to form a highly flexible random coil.

FIG. 2 schematically shows a cavity of a network structure that also has a cross-linked polymer force in a semi-interpenetrating network structure. Non-crosslinked polymer is considered to be a random coil because it can move and deform freely in this cavity, and its diameter d 7? Is statistically the intrinsic viscosity [7?] And weight of the polymer solution. Average molecular weight M and force Calculated by the following formula (M.-M.

Kulicke, R. Kniews e, J. Klein, Preparation, Characterization, solution Properties and Rheological Behavior of Polyacrylamide ", Progress in PoymerScience, 8, 373—4 68 (1982)).

[0019] [Equation 1]

(nm)

[0020] When the diameter of the random coil that has the calculated non-crosslinked polymer force is about 10 times or more the average interval of the network that also has the crosslinked polymer force, the mechanical strength and the fracture energy of the gel having a semi-interpenetrating network structure are reduced. Begin to improve specifically. In other words, the molecular weight of the non-crosslinked polymer in this case is 10 ⁶ or more in terms of weight average molecular weight, and the polymer is present at a concentration at which sufficient physical entanglement can occur. The mechanism by which this phenomenon occurs is that random coils with non-crosslinked polymer force increase as the degree of polymerization increases.

V, when it becomes larger and fills the cavity scattered in the network structure with the cross-linked polymer force, in other words, when the diameter of the random coil with the non-cross-linked polymer force becomes larger than the diameter of the cavity, the cross-linked polymer and It is presumed that the non-crosslinked polymers become physically entangled and these polymers behave like a continuous network by forming pseudo-crosslinking points due to the entanglement. On the other hand, if the diameter of the random coil made of the non-crosslinked polymer is smaller than the diameter of the cavity, a pseudo cross-linking point is not formed between the crosslinked polymer and the non-crosslinked polymer. In this case, the cross-linked polymer swells in the solvent whose viscosity has been increased due to the presence of the non-cross-linked polymer, so that the mechanical strength and fracture energy of the gel are remarkably improved. Absent.

[0021] In addition, when the diameter of the random coil having non-crosslinked polymer force in the semi-interpenetrating network structure is larger than the diameter of the cavity, the mechanical strength and fracture energy of the gel are specifically improved. It can also be explained as follows. In other words, the semi-interpenetrating network structure is a higher order structure having spatially hard, part (dense part of the crosslinked polymer) and soft part (very sparse part of the bridge polymer, ie, non-crosslinked polymer in the cavity). Yes, even if an external force is applied and a stress concentration point occurs in this hard part and a crack occurs, when the crack reaches the soft part, the stress is dissipated at the tip, and the curvature of the crack tip becomes very large. It is a mechanism that the crack growth stops. Therefore, gels with a semi-interpenetrating network structure exceed the stress that can be diffused by non-crosslinked polymers. Unless a very large external force is applied, the crack cannot propagate over a long distance, and even if it breaks microscopically, it does not lead to macroscopic breakage. In other words, in the gel according to the present invention, the critical value leading to macroscopic destruction is remarkably increased, so that it is not destroyed unless a very large external force is applied. If the network structure of the crosslinked polymer is uniform, the critical value that leads to such macroscopic destruction is not significantly improved.

[0022] FIG. 3 shows the deformation of the semi-interpenetrating network structure at the crack tip of the gel according to the present invention and the resistance to crack progression by forming a transient network in the velocity region where the non-crosslinked polymer is present. This is a schematic illustration of the power. The gel according to the present invention shows a speed dependency on the external force, and the optimum external force speed for increasing the strength of the gel is the non-crosslinked polymer in the cavity portion scattered in the network structure of the crosslinked polymer in the semi-interpenetrating network structure. This is considered to correspond to a velocity region in which a transitional network due to entanglement can be formed.

[0023] FIG. 4 schematically shows a velocity region of external force in which a transient network is formed in the non-crosslinked polymer in a concentrated solution state. As shown in Fig. 4, when the crack progress rate at the crack tip is faster than the movement rate of the non-crosslinked polymer, as shown in the lower part of Fig. 3, (B) cutting of the non-crosslinked polymer occurs preferentially from the stretched state. Therefore, it is considered that the mechanical strength and fracture energy of the gel are reduced. On the other hand, when the crack progress rate at the crack tip is slower than the movement speed of the non-crosslinked polymer, slipping of the (A) non-crosslinked polymer occurs preferentially from the stretched state as shown in the lower part of Fig. 3. It is thought that the mechanical strength and fracture energy of the gel are also lowered. Such a reduction in the mechanical strength and fracture energy of the gel can be achieved when the rate of external force applied is significantly slower than the rate of motion of the uncrosslinked polymer in a physically entangled concentrated solution. May behave in a fluid manner, but if it is significantly faster than that, the non-crosslinked polymer loses the time to move and deform, resulting in a glass state. Conceivable.

However, in the semi-interpenetrating network structure, the non-crosslinked polymer in a concentrated solution state forms a transient network due to entanglement in the velocity region during which the non-crosslinked polymer behaves in a fluid state or enters a glassy state. It seems that it will show physical properties similar to rubber Therefore, the stress generated at the crack tip can be diffused. In other words, the transient network formed by the non-crosslinked polymer in the concentrated solution state does not have a chemical cross-linking point and can slide when excessive stress is applied (stress concentration occurs). By friction, stress is converted to heat and diffused. Therefore, it is preferable that the non-crosslinked polymer moves slowly while maintaining fluidity in a state close to a high concentration solution. Incidentally, the elastic modulus of this transitional network must be sufficiently smaller than the elastic modulus of rigid networks composed of cross-linked polymers.

[0025] In short, the voids, which are the network structure force of the crosslinked polymer, and the physical entanglement of the non-crosslinked polymer can avoid stress concentration that acts on cracks and disperse the energy that resists rupture. It becomes "crack prevention".

[0026] Therefore, the mechanical strength and fracture energy of the gel having a semi-interpenetrating network structure vary depending on the relationship between the speed of movement of the non-crosslinked polymer and the speed of the applied external force, and the movement speed of the non-crosslinked polymer Maximum for external force applied at close speed. Therefore, if the kinetic speed of the uncrosslinked polymer is changed by adjusting the gel temperature or the viscosity or compatibility of the solvent that swells the gel, the external force that maximizes the mechanical strength and fracture energy of the gel is obtained. The speed region can be changed.

[0027] Fig. 5 shows the relationship between the fracture energy and the weight average molecular weight M of the non-crosslinked polymer for a gel having a semi-interpenetrating network structure in which a non-crosslinked polymer is entangled with a network structure in which cavities made of a crosslinked polymer are scattered. The correlation is schematically shown. Figure 5 shows the acrylic

w

An example is shown in which a non-crosslinked polymer with polyacrylamide (PAAm) force is entangled with a crosslinked polymer formed from imidomethylpropanesulfonic acid (AMPS) and dibule monomer. Also, in FIG. 5, it is difficult to take out only the semi-interpenetrating network structure strength non-crosslinked polymer and measure its weight average molecular weight M.

w

The correlation with the weight average molecular weight M was grasped, and the weight average molecular weight M of the non-crosslinked polymer in the semi-interpenetrating network structure was estimated.

[0028] As shown in FIG. 5, the breaking energy of the gel increases remarkably near the weight average molecular weight M 1 X 10 ⁶ of the non-crosslinked polymer, and reaches a peak at around 4 X 10 ⁶ . This is non-w

When a random coil made of a crosslinked polymer reaches a weight average molecular weight of M 1 X 10 ⁶

w Start filling the voids scattered in the polymer network, weight average molecular weight M 4 X 10 ⁶

w

It is presumed that this is because the cavity is almost filled with random coils when it reaches the vicinity. Therefore, the size (degree of polymerization) of the non-crosslinked polymer is considered to have an optimum range depending on the size of the cavities scattered in the semi-interpenetrating network structure.

Here, since the non-crosslinked polymer is also a linear polymer having almost no branching, the degree of polymerization, that is, the length of the polymer is approximately linearly proportional to the molecular weight. Therefore, the fact that there is an optimal molecular weight for physical entanglement indicates that there is a length that is well-suited for physically entangled non-crosslinked polymers relative to crosslinked polymers with a network structure. . As can be inferred with reference to Fig. 1, it is expected that the cross-linking polymer will not slip through if the length of the non-crosslinked polymer is not long enough. Alternatively, it can be expected that the non-crosslinked polymer itself cannot constitute a sufficiently wound random coil and cannot form a semi-interpenetrating network structure without being caught by the crosslinked polymer. This may be rephrased that a pseudo cross-linking point is not formed. Therefore, the semi-penetrating network structure is a structure that occurs only when the random coil diameter of the non-crosslinked polymer is much larger than the average interval of the network of the crosslinked polymer.

[0030] In this way, if the gel has a semi-interpenetrating network structure in which a non-crosslinked polymer having a size satisfying the cavity is physically entangled with a rigid network structure having a cross-linked polymer force and a space in which the cavity is scattered, Even when the swelling degree is 5 or more and the weight content of the good solvent is 80% or more at the time of equilibrium swelling with a good solvent, a non-crosslinked polymer is reliably formed when an external force is applied. Therefore, the fracture energy of 700jZm ² or more and 2 OOOjZm ² or less can achieve high durability that can not be achieved in the past.

[0031] Further, this gel has a feature that when a nuclear magnetic resonance measurement is performed at the time of equilibrium swelling with a good solvent, a chemical shift appearing due to the presence of interaction between molecules is not observed. This observation means that there is no intermolecular interaction stronger than hydrogen bonds between non-crosslinked polymers. Thus, if there is no intermolecular interaction stronger than hydrogen bonding between the non-crosslinked polymers, the fluidity and mobility of the non-crosslinked polymer are impaired in the cavities scattered in the network structure of the crosslinked polymer. Therefore, the fracture energy of the gel is effectively improved. [0032] As if to support this, double-network gels exhibiting such high fracture energy cannot be explained by theories proposed for other mechanisms, such as Lake-Thomas theory. First, if estimated by Lake-Thomas theory, the breaking energy is only around lOjZm ² , which is two orders of magnitude lower than the experimental value.

[0033] In addition, this gel is suitable for equilibrium swelling with a good solvent! Thus, the ratio (bZa) of the transient elastic modulus (b) of the non-crosslinked polymer to the elastic modulus (a) of the crosslinked polymer is preferably from ΙΖΙΟΟ to 1Z5. Here, the calculation method of the transient elastic modulus (b) of the non-crosslinked polymer will be described. Creep compliance (J), which is a coefficient of the linear function of strain “e = J σ” for small stress (σ) by observing the strain (e) caused by increasing the stress on the non-crosslinked polymer solution step by step Get. When the creep compliance shows a constant value (steady state compliance) in a certain speed region, the reciprocal of the steady state compliance corresponds to the transient elastic modulus (b) of the non-crosslinked polymer.

[0034] In this way, during equilibrium swelling with a good solvent, the non-crosslinked polymer is stronger than hydrogen bonds and no intermolecular interaction exists, or the non-crosslinked polymer has a transient effect on the elastic modulus of the crosslinked polymer. If the gel has a semi-interpenetrating network structure with an elastic modulus ratio of 1Z100 or more and 1Z5 or less-and even if a crack occurs, the stress is generated at the tip of the crack, and the stress is caused by a transient network of non-crosslinked polymer. Since it is converted into heat by the formation and diffused effectively, the destruction energy is surely 700 jZm ² or more and 2000 jZm ² or less.

[0035] Furthermore, it is preferable that the gel has an equilibrium swelling degree of the crosslinked polymer with a good solvent of 5 to: LOOO, and the weight content of the non-crosslinked polymer is higher than the weight content of the crosslinked polymer. . Further, in this gel, the weight content of the non-crosslinked polymer is preferably 10 to 40% with respect to the total weight of the crosslinked polymer and the good solvent in the gel.

[0036] The cross-linked polymer constituting the gel must be highly rigid with a polymer chain having a high equilibrium swelling degree and a large extension, and specifically, the equilibrium swelling degree with a good solvent is 5%. It is preferably crosslinked so as to be ˜1000 (solvent content 80˜99.9 w%). The mechanical strength of the crosslinked polymer itself does not have to be so high. The initial elastic modulus of the gel is almost determined by the initial elastic modulus of the network structure composed of the crosslinked polymer, and the influence of the non-crosslinked polymer on the initial elastic modulus of the gel is extremely small. Therefore, cross-linked polymers The initial elastic modulus of the gel can be adjusted by adjusting the degree of crosslinking.

[0037] The crosslinked polymer is preferably a strong electrolyte. We have electrolytes

When a gel having a semi-interpenetrating network structure was prepared by combining a Z non-electrolyte cross-linked polymer and an electrolyte Z non-electrolyte non-cross-linked polymer, improvement in mechanical strength was observed for any combination. The only combination that significantly improved the mechanical strength and the fracture energy was a combination of a strong electrolyte or a weakly crosslinked polymer that was completely dissociated and a non-electrolyte non-crosslinked polymer. Therefore, in the present invention, it is preferable to use a combination of a strong electrolyte or a weakly dissociated weakly crosslinked polymer and a non-electrolyte non-crosslinked polymer. Even if the crosslinked polymer is an electrolyte, the degree of shrinkage of the gel is remarkably small even if it is immersed in a solvent having a high ionic strength if it is entangled with the non-crosslinked polymer.

[0038] In addition, this non-crosslinked polymer has characteristics such as non-electrolyte and high flexibility, no interaction such as electrostatic interaction and hydrophobic bond with the crosslinked polymer, or extremely weak if any. It is preferable to have. Here, the non-crosslinked polymer is in the form of a concentrated solution or sol within the network structure composed of the crosslinked polymer, and itself has fluidity like egg white and cannot maintain its outer shape.

[0039] Further, from the viewpoint that the weight content of the non-crosslinked polymer in the gel according to the present invention needs to be higher than the concentration at which the high molecular weight non-crosslinked polymer can generate sufficient physical entanglement, Is preferably in the range of 5 to: LOO mole times. In addition, in the gel during equilibrium swelling with a good solvent, if the concentration of the non-crosslinked polymer is too low or too high, the mechanical strength of the gel will not improve, so 0.5 to 5 molZL (3.5 ~ 35%). Further, when the non-crosslinked polymer does not contain any cross-linked structure, the non-crosslinked polymer has a concentration of 0.5 to 5 molZL (3.5 to 35%) with respect to the solvent and has a molecular weight of Is preferably not less than the lower critical molecular weight described below.

[0040] The lower critical molecular weight of the non-crosslinked polymer, a concentrated solution the molecular weight dependence of the viscosity, than the molecular weight giving the critical point that changes from ~M by entanglement between port Rimmer 7? To ~Μ ³ · ⁴ 10 ~: LOO times larger and its degree of polymerization (number of polymer units) It refers to molecular weight higher than that. If the average molecular weight of the non-crosslinked polymer is equal to or higher than the lower critical molecular weight, the mechanical strength and fracture energy of the gel having a semi-interpenetrating network structure increase with the molecular weight, and if the average molecular weight exceeds the upper critical molecular weight. The mechanical strength and fracture energy of the gel show constant values. Therefore, in the example shown in FIG. 5, the lower critical molecular weight of the non-crosslinked polymer is around the weight average molecular weight M 1 X 10 ⁶ where the fracture energy of the gel begins to increase specifically, and the upper critical critical mass of the non-crosslinked polymer.

w

The molecular weight is around the weight average molecular weight M 4 X 10 ⁶ where the breaking energy of the gel peaks.

w

It turns out that. The lower and upper critical molecular weights of the non-crosslinked polymer vary depending on the size of the cavities scattered in the network structure composed of the crosslinked polymer.

[0041] The volume occupied by the non-crosslinked polymer is preferably equal to or greater than the volume of the vacancies scattered in the network structure composed of the crosslinked polymer, that is, the non-crosslinked polymer is sufficiently entangled in the network structure also having the crosslinked polymer force. It is preferable. In addition, there is a particularly dense portion of the network around the cavity portion scattered in the network structure composed of the crosslinked polymer, and the non-crosslinked polymer is sufficiently entangled with the dense portion. The non-crosslinked polymer present in the part behaves like a crosslinking point when the diffusion rate is significantly slow. Therefore, it is preferable that the non-crosslinked polymer has at least two cross-linking points at both ends across the cavity scattered in the network structure having the cross-linked polymer force, and further has a volume that completely fills the cavity. It is. By the way, the molecular weight of the non-crosslinked polymer is indicated by a statistical average value, and therefore, the non-crosslinked polymer is formed when the both ends of all non-crosslinked polymers straddle the cavities scattered in the network structure of the crosslinked polymer. The average molecular weight of the polymer is the upper critical molecular weight.

[0042] Raw material monomers constituting such a crosslinked polymer and a non-crosslinked polymer include 2-acrylamide-2-methylpropanesulfonic acid (AMPS), acrylamide (AAm), acrylic acid (AA), methacrylic acid, N-isopropylacrylamide, butylpyridine, hydroxyethyl acrylate, butyl acetate, dimethylsiloxane, styrene (St), methyl methacrylate (MMA), trifluoroethyl acrylate (TFE), styrene sulfonate (SS) Or dimethylacrylamide etc. are illustrated. In addition, as a raw material monomer constituting the non-electrolyte non-crosslinked polymer, a fluorine-containing monomer, specifically 2, 2, 2-trifluoroethylene Rumethyl Atarylate, 2, 2, 3, 3, 3 Pentafluoropropyl methacrylate, 3— (Perfluorobutyl) 2 Hydroxypropyl methacrylate, 1H, 1H, 9H Hexadecafluorono-methacrylate, 2, Examples thereof include 2,2-trifluoroethyl attareido, 2, 3, 4, 5, 6 pentafluorostyrene or vinylidene fluoride. For the crosslinked polymer or non-crosslinked polymer, polysaccharides such as dielan, hyaluronic acid, carrageenan, chitin or alginic acid, or proteins such as gelatin and collagen can also be used.

[0043] The gel according to the present invention preferably has a water content of 10 to 99% in pure water, more preferably 50 to 95%, and even more preferably 85 to 95%. If the gel contains a large amount of pure water, the solvent absorption rate of the gel is increased and the permeability thereof is improved. At the same time, such a gel is a highly water-absorbent resin, soft contact lens, or liquid chromatography. It is useful for applications such as single-use separation frames, or applications that require sustained release.

[0044] Further, this gel preferably has a volume retention rate of 20 to 95%, more preferably 60 to 95%, and particularly preferably 70 to 95% when transferred from pure water to physiological saline. In addition, this gel has the feature that even if it is once dried, it can be re-swelled to restore its original physical properties, and the solvent at the time of re-swelling is not limited to water. Therefore, if this gel is used as a water-absorbing agent such as Omumu, it can absorb a large amount of a solution with high osmotic pressure such as urine. Can be provided.

[0045] Further, with respect to this gel, another polymer may be entangled with a semi-interpenetrating network structure constituted by a crosslinked polymer and a non-crosslinked polymer. Since the surface layer of this semi-interpenetrating network structure is dominated by the last added polymer, if the other polymer is entangled with the semi-interpenetrating network structure, the other polymer properties are imparted to the gel. can do. Therefore, if the technique disclosed in Patent Document 1 is used to form a free end chain by mixing an electrolyte polymer or graft polymerization into this semi-interpenetrating network structure, the mechanical strength and fracture energy are extremely high. This is achieved by obtaining high and low friction materials.

[0046] Further, the side chain of the non-crosslinked polymer constituting this semi-interpenetrating network structure is known means. By chemically modifying the gel, the kinetics of the non-crosslinked polymer can be changed to adjust the swelling property, fracture energy and viscoelastic properties of the gel.

[0047] Further, by immersing the gel according to the present invention in a polyvalent ion-containing solution to swell, the cross-linked polymer or non-cross-linked polymer constituting the semi-interpenetrating network structure and the above-described many functional groups are included. By reacting a valence ion, a chelate complex or a colloid containing a polyvalent ion is formed on the surface and inside of the semi-interpenetrating network structure, and the physical properties of the gel can be changed. In general, when the content of metal ions in a gel increases, the water content decreases and the mechanical strength increases. In the gel according to the present invention, when an external force is applied, the non-crosslinked polymer needs to form a transient network. Therefore, the network structure, which is also a crosslinked polymarker, and the polyvalent ions form a colloid, and It is preferable that the non-crosslinked polymer does not form a colloid with the multivalent ion. Further, the content of polyvalent ions in the gel is preferably 0.01 to Lmol / L at the time of equilibrium swelling with pure water, and more preferably 0.03 to 0.3 mol / L. Further, the polyvalent ion is not particularly limited as long as it is a metal ion capable of forming a complex, and examples thereof include zinc ion, iron ion, nickel ion, cobalt ion, and chromium ion. In addition, examples of the functional group capable of forming a complex with these multivalent ions include a carboxyl group, a sulfonic acid group, and a phosphoric acid group.

[0048] Further, by adjusting the surface potential of the gel according to the present invention, endothelial cells can be attached to the surface and allowed to proliferate. Therefore, by selecting the type of the non-crosslinked polymer that governs the physical properties of the surface layer of the semi-interpenetrating network structure in the gel according to the present invention, or by chemically modifying the side chain of the non-crosslinked polymer, An extremely durable substrate for cell culture can be obtained.

[0049] Further, as described above, a non-crosslinked polymer having high flexibility satisfying a predetermined condition penetrates into a rigid network structure including a crosslinked polymer and in which cavities are scattered. The mechanical strength and durability of these industrial materials can be improved by using the gel of the present invention to constitute a water-absorbent resin, a lubricant, a cell culture substrate and the like.

[0050] The method for producing a gel having a semi-interpenetrating network structure according to the present invention is not particularly limited! /, But first, radically copolymerization of monomers having different reactivities to disperse the cavities. Next, the cross-linked polymer is formed, and then the cross-linked polymer does not contain a cross-linking agent, and the monomer solution force is immersed in the monomer solution while the non-cross-linked polymer is entangled with the cross-linked polymer by radical polymerization. Legal is preferred. In addition, in order to make the voids scattered in the network structure composed of a crosslinked polymer larger, a monomer having a different reactivity is radically copolymerized to form a polymer, and another crosslinking agent is added to the polymer solution. A method of further polymerizing the polymers by gamma ray irradiation or the like is preferable. Further, the gel having the semi-interpenetrating network structure may be further immersed in another monomer solution, and the third and fourth non-crosslinked polymers may be entangled with the gel.

[0051] In the formation of a network structure having such a crosslinking polymer force, 0.001 to 0.1 mol times dibule monomer is added as a crosslinking agent to an appropriate concentration of electrolyte bulule monomer, and these are combined with radicals. It is preferable to polymerize. Examples of the cross-linking agent include N, N′-methylene bisacrylamide (MBAA) and ethylene glycol dimetatalylate. By the way, when using weak electrolyte bull monomers, it is necessary to increase the degree of dissociation and to initiate the reaction with force by exchanging counterions and controlling pH. Further, by adding the poor solvent to the reaction system for producing the crosslinked polymer, the non-uniformity of the network structure composed of the crosslinked polymer can be enhanced. In addition, when the crosslinked polymer is radically polymerized, non-uniformity of the network structure may be increased by mixing fine particles inside the network structure and removing the fine particles by dissolution after the formation of the network structure. .

[0052] In addition, when the non-crosslinked polymer is entangled with the network structure composed of the crosslinked polymer by using the sequential polymerization method, the crosslinked polymer may be equilibrated and swollen even if the solvent is removed or just after the synthesis. It may be. Furthermore, after the crosslinked polymer is immersed in the monomer solution of the non-crosslinked polymer and becomes in an equilibrium swelling state, that is, after the monomer concentration is almost equal between the inside and the outside of the network structure, the polymerization of the monomer is not performed for the first time. It is preferable that the In this monomer solution, the concentration of the cross-linking agent such as dibule monomer with respect to the monomer needs to be less than 0. 01 mol%. According to such a sequential polymerization method, since the non-crosslinked polymer is polymerized in a state where the crosslinked polymer is sufficiently swollen, even if the non-crosslinked polymer is entangled with the crosslinked polymer, the volume increase rate remains at most several tens of percent. . In addition, the third and fourth polymers are further entangled with this semi-interpenetrating network structure. For this purpose, the same means as the polymerization means for the non-crosslinked polymer described above may be used.

[0053] In order to form a colloid containing a multivalent ion on the surface and inside of this semi-interpenetrating network structure, the gel produced by the above-mentioned method was once vacuum dried and then dried. Soak the gel in a solution containing multivalent ions.

Example

[0054] First, as a comparative control of the gel according to the present invention, using the method described in Example 1 in Patent Document 2, a network structure in which cavities made of a crosslinked polymer are scattered is used. % Second polymer ”penetrated and physically entangled! /, And a gel having a semi-interpenetrating network structure was prepared. Specifically, it is as follows.

[0055] (Comparative Example 1)

A frame with an outer length of 80 X 80 mm and a width of 5 mm was cut out from a 100 X 100 X 2 mm silicone resin board with a cutter, and a 3 mm groove was made in one part of the frame. The silicone resin frame was sandwiched between two 100 × 100 × 3 mm glass plates to assemble a polymerization vessel.

[0056] 25 mol of 2 molZL 2-acrylamide 2-methylpropanesulfonic acid (AMPS) aqueous solution as a monomer, 1 ml of 2 molZL N, N'-methylenebisacrylamide (MBAA) aqueous solution as a crosslinking agent, and 0. 50 ml of an aqueous solution was obtained by combining with 1 ml of a 2-oxodaltalic acid aqueous solution of ImolZL and adjusting with water.

[0057] This aqueous solution was deoxygenated using nitrogen gas. Then, after pouring this deoxygenated aqueous solution into the opening of the silicon resin plate placed on one glass plate of the polymerization container, the other glass plate is stacked on the silicon plate and the periphery of the opening is sealed. By using UV lamp (22W, 0.34A) with a wavelength of 365nm and irradiating with UV light at room temperature for 6 hours, the gel has a non-uniform network structure with a degree of cross-linking of 4 mol% and scattered cavities. (Semi-finished product) was produced. The calculation of the degree of crosslinking is as follows.

[0058] {(MBAA aqueous solution concentration X amount) Z (monomer concentration X amount)} X 100

= {(2mol / L X lml) / (2mol / L X 25ml)} X 100

= 4mol%

<Formation of interpenetrating network structure or semi-interpenetrating network structure> Mix 40 ml of 5 molZL acrylamide (AAm) aqueous solution as a monomer, 1 ml of 0.2 molZL MBAA aqueous solution as a cross-linking agent, and 1 ml of 0.2 mol aqueous solution of ImolZL 2-oxoglutaric acid and adjust with water. 200 ml of an aqueous solution (immersion solution) was obtained. This soaking solution was deoxygenated using nitrogen gas. The initiator concentration at this time was 0.1 mol%. The calculation of the degree of crosslinking is as follows.

[0060] {(0. 2mol / L X lml) / (5mol / L X 40ml)} X 100

= 0. Lmol%

[0061] Next, the soaking solution and 4 g of the gel (semi-finished product) were placed in a sealed container having a capacity sufficiently larger than the gel. This container was placed in a refrigerator at 4 ° C. for 24 hours, and the monomer, crosslinking agent and initiator in the soaking solution were diffused and penetrated into the gel. During this process, the container was occasionally gently shaken to make the concentration of the immersion solution uniform. In this process, the gel (semi-finished product) is swelled in equilibrium to increase its volume by about ten times, the non-uniformity of the network is expanded, and a network structure in which cavities are scattered is formed.

[0062] Next, the gel (semi-finished product) was taken out from the dipping solution, cut into an appropriate size, and then the gel was sandwiched between two 100 X 100 X 3mm glass plates so that no air bubbles were mixed. After sealing the four sides around the two glass plates, ultraviolet rays were irradiated for 6 hours at room temperature using a 365 nm wavelength UV lamp (30 W, 0.68 A). At this time, a gel having an interpenetrating network structure or a semi-interpenetrating network structure was obtained by polymerization of the AAm monomer diffused in the gel to produce a second polymer. The degree of crosslinking of the second polymer in this gel was 0.1 mol%. The calculation of the degree of crosslinking is as follows.

[0063] {(0. 2mol / L X lml) / (5mol / L X 40ml)} X 100

= 0. Lmol%

[0064] The gel having the interpenetrating network structure or semi-interpenetrating network structure obtained in this manner was equilibratedly swollen in pure water (good solvent). In the gel during parallel swelling with pure water, the weight content of the bridge polymer is 1.5%, the weight content of the second polymer is 10.5%, and the weight content of pure water is 88%. The equilibrium swelling degree of the crosslinked polymer was 44, and the equilibrium swelling degree of the gel itself was 8. [0065] Then, for this gel, "initial elastic modulus", "compressive strength", "breaking energy" and "presence / absence of intermolecular interaction stronger than hydrogen bond" were measured by the following means. The composition and measured properties of this gel are summarized in “Table 1” below.

[0066] (Example 1) to (Example 3)

A gel having a semi-interpenetrating network structure was prepared in the same manner as in Comparative Example 1 except that the following points in the formation of an interpenetrating network structure or a semi-interpenetrating network structure> were changed.

[0067] 40 ml of a 5 mol ZL acrylamide (AAm) aqueous solution as a monomer and 0.

ImolZL 2-oxoglutaric acid aqueous solution lZ20ml (50μ1) was mixed and adjusted with water to obtain 200ml of aqueous solution (immersion solution). The initiator concentration in this soaking solution is 0.005 mol%. The calculation of the initiator concentration is as follows.

[0068] {(0. lmol / L X l / 20ml) / (5mol / L X 40ml)} X 100

= 0. 005mol%

[0069] In addition, the gel (semi-finished product) sandwiched between two glass plates after being taken out from the dipping solution was irradiated with ultraviolet rays at room temperature using a 365 nm wavelength UV lamp (30W, 0.6A). By irradiating for 10 hours in Example 1, 8 hours in Example 2, and 6 hours in Example 3, the network structure in which cavities constituting the gel (semi-finished product) are scattered has a predetermined weight average molecular weight M. When a non-crosslinked polymer is formed, it is entangled and has a semi-interpenetrating network structure.

A gel was obtained.

[0070] Each of the gels having a semi-interpenetrating network structure obtained in this manner was equilibratedly swollen in pure water (good solvent). In each gel in parallel swelling with pure water, the weight content of the crosslinked polymer is 1.5%, the weight content of the non-crosslinked polymer is 10.5%, and the weight content of pure water is 88%. The equilibrium swelling degree of the crosslinked polymer was 44, and the equilibrium swelling degree of the gel itself was 8. The composition and measured properties of these gels are summarized in “Table 1” below.

[Example 4]

The polyacrylamide (PAAm), which is a non-crosslinked polymer in a gel having a semi-interpenetrating network structure obtained in the same manner as in Example 3, was chemically treated using the following means. Modified.

[0072] <Chemical modification of PAAm side group by Mannich reaction>

Dissolve 1.2 ml of 35% formaldehyde aqueous solution in 150 ml of pure water, calorie triethylamine, adjust to pH 9.0, and heat to 70 degrees. In this hot reaction solution, 25 g of a plate-like (about 5 mm thick) gel that reached equilibrium swelling in pure water was added to initiate the methylolation reaction. After 1 hour from the start of the reaction, this plate-like gel was taken out of the reaction system and swollen in a large excess of cold water to stop the methylol cocoon reaction. When the introduction rate of methylol groups introduced into PAAm by this reaction was calculated by a known method, it was about 30%.

[0073] The gel having a semi-interpenetrating network structure obtained in this manner was subjected to equilibrium swelling again in pure water. In the gel in parallel swelling with pure water, the weight content of the crosslinked polymer is 1.5%, the weight content of the non-crosslinked polymer is 12.5%, and the weight content of pure water is 86%. Yes, the equilibrium swelling degree of the crosslinked polymer was 44, and the equilibrium swelling degree of the gel itself was 7.4. The composition and measured properties of this gel are summarized in “Table 1” below.

[0074] (Comparative Example 2)

A frame with an outer length of 80 x 80 mm and a width of 5 mm was cut out from a 100 x 100 x 0.1 mm silicone resin board with a cutter, and a 3 mm groove was made in one part of this frame. The silicone resin frame was sandwiched between two 100 × 100 × 3 mm glass plates to assemble a polymerization vessel.

[0075] 25 ml of a 2 mol ZL AMPS aqueous solution as a monomer, 8 ml (125 1) of a 2 mol ZL MB AA aqueous solution as a cross-linking agent, and 1 ml of an ImolZL 2-oxodaltalic acid aqueous solution as an initiator were mixed with water. Adjustment was performed to obtain 50 ml of an aqueous solution.

[0076] This aqueous solution was deoxygenated using nitrogen gas. Subsequently, the deoxygenated aqueous solution is poured into an opening of a silicon plate placed on one glass plate of the polymerization vessel, and the other glass plate is overlaid on the silicon plate to seal the periphery of the opening, and then the wavelength. By using a 365nm UV lamp (30W, 0.668A) for UV irradiation at room temperature for 6 hours to polymerize, a gel with a network structure with a cross-linking degree of 0.5 mol% and interspersed cavities (semi-finished product) ) It was. The calculation of the degree of crosslinking is as follows.

[0077] {(MBAA aqueous solution concentration X amount) Z (monomer concentration X amount)} X 100

= {(2mol / L X 0. 125ml) / (2mol / L X 25ml)} X 100

= 0.5mol%

Mix 40 ml of 5 molZL acrylamide (AAm) aqueous solution as monomer, 1 ml of MBAA aqueous solution as 2 molZL as crosslinking agent, and 20 ml (50 μ1) of 2-Zoglutarate aqueous solution of 0.ImolZL as initiator. 200 ml of an aqueous solution (immersion solution) was obtained by adjusting with water. The soaking solution was deoxygenated using nitrogen gas. The initiator concentration in this soaking solution is 0.005 mol%. The calculation of the initiator concentration is as follows.

[0079] {(0. lmol / L X l / 20ml) / (5mol / L X 40ml)} X 100

= 0. 005mol%

[0080] Next, 0.3 g of the soaking solution and the gel (semi-finished product) was placed in a sealed container having a capacity sufficiently larger than the gel. This container was placed in a refrigerator at 4 ° C. for 24 hours, and the monomer, crosslinking agent and initiator in the immersion solution were diffused and permeated into the gel (semi-finished product). During this process, the container was sometimes gently shaken to make the concentration of the immersion solution uniform. In this process, the gel (semi-finished product) was equilibrium swollen and its volume increased more than 250 times.

[0081] Next, after the gel (semi-finished product) was taken out from the soaking solution and cut into an appropriate size, air bubbles were mixed between the glass plates using two glass plates of 100 X 100 X 3mm. Clamped so as not to enter. After sealing the four sides around the two glass plates, ultraviolet rays were irradiated at room temperature for 10 hours using a UV lamp (30 W, 0.68 A) having a wavelength of 365 nm. At this time, a gel having an interpenetrating network structure or a semi-interpenetrating network structure was obtained by polymerization of the AAm monomer diffused in the gel.

[0082] The gel thus obtained was subjected to equilibrium swelling in pure water. In the gel during parallel swelling with pure water, the weight content of the crosslinked polymer is 0.1%, the weight content of the second polymer is 5.9%, and the weight content of pure water is 94%. Yes, the equilibrium swelling degree of the crosslinked polymer was 1360, and the equilibrium swelling degree of the gel itself was 17. Composition and measurement of this gel The characteristics are summarized in “Table 1” below.

[0083] (Comparative Example 3)

In Comparative Example 1, the weight content of AMPS and MBAA used in the formation of a network structure in which cavities having cross-linked polymer strength are scattered> and <formation of an interpenetrating network structure or a semi-interpenetrating network structure> A gel having an interpenetrating network structure or a semi-interpenetrating network structure was obtained in the same manner except that the weight content of AAm and MBAA used was changed.

[0084] The gel thus obtained was subjected to equilibrium swelling in pure water. In the gel during parallel swelling with pure water, the weight content of the crosslinked polymer is 0.7%, the degree of crosslinking of the crosslinked polymer is 2 mol%, and the weight content of the second polymer is 9.3%. The degree of crosslinking of the second polymer was 0.1 mol%, the weight content of pure water was 90%, the equilibrium swelling degree of the crosslinked polymer was 103, and the equilibrium swelling degree of the gel itself was 10. . The composition and measured properties of this gel are summarized in “Table 1” below.

[0085] (Comparative Example 4)

A gel having a semi-interpenetrating network structure was obtained in the same manner as in Comparative Example 1 except that MBAA was not used in the formation of an interpenetrating network structure or a semi-interpenetrating network structure>.

[0086] The gel thus obtained was subjected to equilibrium swelling in pure water. In the gel at the time of parallel swelling with pure water, the weight content of the crosslinked polymer is 1.5%, the degree of crosslinking of the crosslinked polymer is 4 mol%, and the weight content of the non-crosslinked polymer is 10.5%, The weight content of pure water was 88%, the equilibrium swelling degree of the crosslinked polymer was 44, and the equilibrium swelling degree of the gel itself was 8. The composition and measured properties of this gel are summarized in “Table 1” below.

[0087] (Comparative Example 5)

A gel having a semi-interpenetrating network structure was obtained in the same manner as in Comparative Example 1 except that the formation of the interpenetrating network structure or semi-interpenetrating network structure> was changed as follows.

[0088] <Formation of semi-interpenetrating network structure gel> Mix 40 ml of 5 molZL acrylamide (AAm) aqueous solution as monomer and 1 ml of 0. ImolZL 2-oxodaltaric acid aqueous solution as initiator, and then add 5.6 1 2-methylcaptoethanol as chain transfer agent. The solution was adjusted with water to obtain 200 ml of an aqueous solution (immersion solution). The immersion solution was deoxygenated using nitrogen gas. The initiator concentration in this immersion solution is 0.1 mol%. The calculation of the initiator concentration is as follows.

[0089] {(0. 2mol / L X lml) / (5mol / L X 40ml)} X 100

= 0. Lmol%

Next, 4 g of the soaking solution and gel (semi-finished product) were placed in a seal container having a capacity sufficiently larger than the gel. This container was placed in a refrigerator at 4 ° C. for 24 hours, and the monomer, crosslinking agent and initiator in the soaking solution were diffused and permeated into the gel. During this process, the container was sometimes gently shaken to make the concentration of the immersion liquid uniform. In this step, the gel swells and becomes approximately ten times larger in volume, thereby increasing the non-uniformity of the network structure and forming a network structure in which cavities are scattered.

[0091] Next, after the gel is taken out from the soaking solution and cut into an appropriate size, this gel is used with two glass plates of 100 X 100 X 3mm so that air bubbles do not mix between the glass plates. I pinched it. After sealing the four sides around the two glass plates, ultraviolet rays were irradiated at room temperature for 10 hours using a UV lamp (30 W, 0.68 A) with a wavelength of 365 nm. At this time, a gel having a semi-interpenetrating network structure was obtained by polymerization of the AAm monomer diffused in the gel.

[0092] The gel thus obtained was equilibrated and swollen in pure water. In the gel at the time of parallel swelling with pure water, the weight content of the crosslinked polymer is 1.6%, the degree of crosslinking of the crosslinked polymer is 4 mol%, and the weight content of the non-crosslinked polymer is 8.2%. The weight content of pure water was 89%, the equilibrium swelling degree of the crosslinked polymer was 44, and the equilibrium swelling degree of the gel itself was 8.5. The composition and measured properties of this gel are summarized in “Table 1” below.

[0093] (Comparative Example 6)

A gel having a semi-interpenetrating network structure was prepared in the same manner as in Comparative Example 1 except that the formation of an interpenetrating network structure or a semi-interpenetrating network structure> was changed as follows. Obtained.

[0094] <Formation of semi-interpenetrating network structure gel>

Mix 40ml of 5molZL acrylamide (AAm) aqueous solution as monomer and 0.ImolZL 2-oxoglutaric acid aqueous solution lZ20ml (50μ1) as initiator, and adjust with water to obtain 200ml of aqueous solution (immersion solution). It was. The immersion solution was deoxidized using nitrogen gas. The initiator concentration in this immersion solution was 0.005 mol%. The initiator concentration is calculated as follows.

[0095] {(0. lmol / L X l / 20ml) / (5mol / L X 40ml)} X 100

= 0. 005mol%

[0096] Next, 4 g of the dipping solution and gel (semi-finished product) were placed in a seal container having a capacity sufficiently larger than the gel. This container was placed in a refrigerator at 4 ° C. for 24 hours, and the monomer, crosslinking agent and initiator in the soaking solution were diffused and permeated into the gel. In this process, the container was sometimes gently shaken to make the concentration of the immersion liquid uniform. In this step, the gel is equilibrium swollen and its volume is increased by about ten times, so that the non-uniformity of the network structure is expanded and a network structure in which cavities are scattered is formed.

[0097] Next, the immersion solution strength gel is taken out and cut into an appropriate size, and then the gel is used with two glass plates of 100 X 100 X 3mm so that air bubbles are not mixed between the glass plates. I pinched it. After sealing the four sides around the two glass plates, ultraviolet rays were irradiated for 10 hours at room temperature using a 365 nm wavelength UV lamp (30W, 0.68A). A gel having a semi-interpenetrating network structure was obtained by polymerizing the AAm monomer diffused in the gel to produce a non-crosslinked polymer.

[0098] <Chemical modification of PAAm side group by Mannich reaction>

Dissolve 1.2 ml of 35% formaldehyde aqueous solution in 150 ml of pure water, calorie triethylamine, adjust to pH 9.0, and heat to 70 degrees. In this hot reaction solution, 25 g of the gel having the plate-like (thickness: about 5 mm) semi-interpenetrating network structure that reached equilibrium swelling in pure water was added to start the methylol-moist reaction. . After 1 hour from the start of the reaction, an additional 9.5 ml of 50% aqueous dimethylamine solution was added to the hot reaction solution. After 30 minutes, the gel is taken out of the reaction system and swollen in a large excess of cold water. The reaction was stopped. The introduction rate of methylol group and cation group introduced into PAAm by this reaction was calculated by a known method, and each was about 30%.

[0099] The thus-obtained gel having a methylol candy and a cationized semi-interpenetrating network structure was again subjected to equilibrium swelling in pure water. In the gel during parallel swelling with pure water, the weight content of the crosslinked polymer is 2.2%, the weight content of the non-crosslinked polymer is 14.8%, and the weight content of pure water is 83%. %, The equilibrium swelling degree of the crosslinked polymer was 44, and the equilibrium swelling degree of the gel itself was 6. The composition and measured properties of this gel are summarized in “Table 1” below.

[0100] [Measurement of gel properties]

To measure the “initial modulus” and “compressive strength” of the gel, ORIENTIC TENSILON model RTC-1150A (tester A) or ORIENTIC TENSILON model RTC-1150A model RTC-1150A (tester B) And attachment fittings manufactured by Arai Seisakusho Co., Ltd. were used. Testing machine A can measure stresses of 250N or less, and testing machine B can measure stresses of 10kN or less, and it was used depending on the mechanical strength of the gel to be measured.

[0101] First, a compression test was performed, and the gel was cut into a cylindrical shape with a thickness of about 5 mm using a circular cutter with a diameter of 9 mm, and the attachment metal (upper and lower compression plate type) connected to testing machine A or B was used. The stress generated in the gel was measured at a compression rate of 10% Zmin (for example, 0.5 mm / min for a 5. Omm thick gel) with respect to the strain in the height direction.

[0102] The initial elastic modulus of the gel was calculated from the slope of the curve in the region where the strain of the strain-stress curve obtained by the compression test was less than 10% and high in linearity by the following equation. The compressive strength of the gel is the stress when the slope of the strain-stress curve output to the monitor changes in real time during the measurement due to the gel being destroyed, or the strain-stress curve output to the monitor. Even if the slope of the film did not change, the following formula was calculated from the stress and the surface area when the fracture of the gel was confirmed.

[0103] (Initial modulus) = (Stress) I (Strain)

(Compressive strength) = (Stress at break) / (Surface area without deformation)

[0104] Further, the breaking energy of the gel was also measured using the tester A or B. The breaking energy of the gel is cut with JIS K-6252 Truza type 1/2 size metal cutter. Extruded thickness 4.0 ~ 5. Fix the Omm gel with the attachment bracket (fixing device for tensile test), and perform the tear test at a speed of 500mmZmin under the condition that steady fracture occurs. Was calculated by applying to the following equation.

[0105] Normally, as the destroyed surface, the force that can obtain two surfaces on both sides, such as the left and right or top and bottom of the destruction, with reference to the destruction position. think of.

[0106] (Fracture energy) = (Work required for steady fracture) / (Fracture area)

= (Average force at steady state failure) Z (gel thickness)

[0107] Regarding the “presence / absence of intermolecular interaction stronger than hydrogen bonding” between non-crosslinked polymers or between second polymers, a nuclear magnetic resonance measurement was performed on the gel, and the presence of intermolecular interaction was determined. Judgment was made based on whether or not the chemical shift that should appear was observed.

[0108] The weight average molecular weight M of the non-crosslinked polymer in the semi-interpenetrating network structure is

2) The correlation between the polymerization conditions of the non-crosslinked polymer and its weight average molecular weight M was ascertained, and the polymerization condition force of the non-crosslinked polymer was calculated based on the correlation.

[0109] [Table 1]

By comparing the composition and properties of the gels obtained in Examples 1 to 3. Thus, it can be seen that the fracture energy of the gel improves as the weight average molecular weight M of the non-crosslinked polymer constituting the semi-interpenetrating network structure increases. In Table 1, the weight average molecular weight M of the unbridged polymer (B) is expressed as an exponential function with base 10.

[0111] This specification is based on Japanese Patent Application No. 2004-187954 filed on Jun. 25, 2004. All this content is included here.

Industrial applicability

[0112] The Hyde Mouth Gel according to the present invention is transparent with high mechanical strength and fracture strength, and has flexibility, substance permeability and impact resistance. Materials, building materials, communication materials (e.g. bearings, cables and joints), soil modifiers, contact lenses, intraocular lenses, hollow fibers, artificial cartilage, artificial joints, artificial organs (e.g. artificial blood vessels and artificial skins) ), Fuel cell materials, knottery separators, bedsore prevention mats, cushions, lubricants, lotions and other stabilizers and thickeners, cell culture substrates, drug delivery systems (DDS), It can be used as a drug carrier, a sensor for a specific substance, or a software computer used at the tip of a force tail.

Claims

The scope of the claims

[1] It has a semi-interpenetrating network structure in which a non-crosslinked polymer invades and physically entangles into a network structure composed of crosslinked polymers.

A gel having a swelling degree of 5 or more, a weight content of the good solvent of 80% or more, and a breaking energy of 700 jZm ² or more and 2000 jZm ² or less during equilibrium swelling with a good solvent.

[2] The gel according to claim 1, wherein, during equilibrium swelling with the good solvent, there is no intermolecular interaction stronger than hydrogen bonds between the non-crosslinked polymers.

[3] The non-crosslinked polymer has an equilibrium swelling degree with the good solvent of 5 to: LOOO,

The non-crosslinked polymer has a weight content higher than the weight content of the crosslinked polymer,

The gel according to claim 1.

[4] The gel according to claim 1, wherein the non-crosslinked polymer has a weight content of 3.5 to 35% with respect to the weight of the good solvent in the gel.

[5] The gel according to claim 1, wherein a weight content of the non-crosslinked polymer is 10 to 40% with respect to a total weight of the crosslinked polymer and the solvent in the gel.

[6] The raw material monomer of the crosslinked polymer and the non-crosslinked polymer is 2 acrylamide

2-methylpropanesulfonic acid (AMPS), acrylamide (AAm), acrylic acid (AA), methacrylic acid, N-isopropylacrylamide, butylpyridine, hydroxyethyl acrylate, vinylol acetate, dimethylol siloxane, styrene (St), Methyl methacrylate HMMA), trifluoroethyl acrylate (TFE), styrene sulfonate (SS), dimethyl acrylate, 2, 2, 2 trifluoroethyl acrylate, 2, 2, 3, 3, 3 pentafur Chloropropyl methacrylate, 3 (perfluorobutyl) 2 hydroxypropyl methacrylate, 1H, 1H, 9H hexadecafluorono-metatalylate, 2, 2, 2 trifluoromethyl etherate, 2, The gel according to claim 1, which is selected from 3, 4, 5, 6 pentafluorostyrene and vinylidene fluoride.

7. The gel according to claim 1, wherein the crosslinking agent used for the polymerization of the crosslinked polymer is N, N′-methylenebisacrylamide (MBAA) or ethylene glycol dimetatalylate.

8. The gel according to claim 1, wherein the molar ratio of the raw material monomer of the crosslinked polymer and the raw material monomer of the non-crosslinked polymer is about 1:20.

[9] The gel according to [1], wherein the surface layer of the semi-interpenetrating network has a free end chain that also has an electrolyte polymer force.

[10] The water-absorbent resin obtained by removing the gel force solvent according to claim 1.

[11] The lubricant having gel force according to claim 1.

[12] A cell culture substrate comprising the gel according to claim 1.

[13] A step of obtaining a gel as an intermediate product comprising the crosslinked polymer and the solvent by polymerizing the first raw material monomer together with a crosslinking agent in a solvent to form a crosslinked polymer having a network structure; ,

After the second raw material monomer is diffused and permeated into the semi-finished gel, it is polymerized to form a non-crosslinked polymer, and this non-crosslinked polymer is physically entangled with the network structure and includes a V-shaped structure. Obtaining a gel as a final product, and a manufacturing method comprising:

A genore having a degree of swelling of 5 or more at the time of equilibrium swelling with the solvent, a weight content ratio of the solvent of ¾0% or more, and a fracture energy of 700 jZm ² or more and 2000 jZm ² or less.

[14] The gel according to [13], wherein the production method further comprises a step of immersing in a multivalent ion-containing solution to form a colloid therein.

15. The gel according to claim 13, wherein the weight content of the non-crosslinked polymer is 10 to 40% with respect to the total weight of the crosslinked polymer and the solvent in the gel.

[16] The raw material monomer is 2 acrylamide-2 methylpropane sulfonic acid (AMPS), acrylamide (AAm), acrylic acid (AA), methacrylic acid, N-isopropyl acrylamide, butylpyridine, hydroxyethyl acrylate. Vinyl acetate, dimethylsiloxane, styrene (St), methyl methacrylate (MMA), trifluoroethyl acrylate (TFE), styrene sulfonic acid (SS), dimethylacrylamide, 2, 2, 2-trifluoro Tylmethyl akujire, 2, 2, 3, 3, 3 Pentafunole P P-Pinole metaclay, 3 (Penoleph butyl) 2 Hydroxypropyl metatalylate, 1H, 1H, 9H—Hexadecafluo 14. The gel according to claim 13, which is selected from Lonoh-methacrylate, 2,2,2-trifluoroethylatreate, 2, 3, 4, 5, 6-pentafluorostyrene, vinylidene fluoride force.

17. The gel according to claim 13, wherein the crosslinking agent is N, N, monomethylene bisacrylamide (MBAA) or ethylene glycol dimetatalylate.

18. The gel according to claim 13, wherein the molar ratio of the first raw material monomer to the second raw material monomer is about 1:20.

[19] In a gel having a semi-interpenetrating network structure in which a non-crosslinked polymer invades and physically entangles with a network structure composed of a crosslinked polymer, the side chain of the noncrosslinked polymer is chemically modified, or the crosslinked polymer is crosslinked. The method for producing a gel, wherein the gel breaking energy is adjusted in a range of 700 j / m ² or more and 2000 j / m ² or less by adjusting the degree.