WO2002057368A1

WO2002057368A1 - Low friction hydrogel having straight chain polymer and method for preparation thereof

Info

Publication number: WO2002057368A1
Application number: PCT/JP2001/007776
Authority: WO
Inventors: Yoshihito Osada; Jian Ping Gong
Original assignee: Hokkaido Technology Licensing Office Co., Ltd.
Priority date: 2001-01-22
Filing date: 2001-09-07
Publication date: 2002-07-25
Also published as: JP2002212452A; JP5048183B2; US20040116305A1

Abstract

A low friction hydrogel which comprises a polymer gel and, admixed therewith or graft-polymerized thereto, a straight chain polymer; and a method for preparing the hydrogel. The hydrogel exhibits improved low friction property over a conventional material.

Description

Specification

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a low-friction hydrogel having a linear polymer and a method for producing the same.

Background technique

To achieve mechanical movement with low friction, ball bearings are usually used, or sliding friction is achieved in the presence of lubricants such as silicone oil and glycerin. In the former case, not only is the device complicated, but also the disadvantage is that friction increases at low speeds. In the latter case, the lubricant must be replenished successively for desorption and elution of the lubricant, and there is a problem with the sustainability of the effect. There have been few examples of low friction motion without a lubricant, and there are only examples using ultra-high molecular weight polyethylene or Teflon.In these cases, the friction coefficient cannot be less than 0.01. Have difficulty.

On the other hand, the polymer hydrogel is revealed ahead of coefficient of friction surface than are other solid materials is very small the 1 0 one ^half to one 0 inventors worldwide (J. Phys Chem.B, 101,5487-5489 (1997), J.Chem.Phys., 109,8062-8068 (1998), J.Phys.Chem.B, 103,6001-6006 (1999), J.Phys Chem.B, 103,6007-6014 (1999), The Japan Academy, 75,122-126 (1999) J.Phys.Cem.B, 104,3423-3428 (2000),) Elucidation and application to artificial joints are expected.

Japanese Patent Application Laid-Open No. H10-500000 describes a curable material containing polymer matrix such as silicone polymer and hydrated gel, which is used for repairing injured parts such as joints and surface finishing. Have been. Hydrated gels are made of hydrophilic, water-insoluble polymers and reduce surface friction.

Japanese Patent Application Laid-Open No. 8-195599 describes a medical device having a layer formed on a surface of a medical device comprising a water-soluble and water-swellable polymer having a reactive functional group and an antithrombotic agent when wetted. Is described. The hydrogel layer immobilized on the surface of medical devices such as catheters becomes a lubricating layer and reduces friction.

6- 7 1 8 1 8 is a fiber base fabric and a resin skin containing water-soluble alginate. An underwater garment using a composite sheet made of a membrane and having low frictional resistance to water is described.

As described above, in the development of medical devices and the like, materials with low frictional resistance on the material surface have been developed.However, considering the application to artificial joints and the like, the friction coefficient of the joint is 0.001 to 0. 0.3, which is not satisfactory in terms of realizing low-friction materials at the same level as in vivo and low friction at low speed.

Disclosure of the invention

Therefore, an object of the present invention is to provide a further low-friction material to satisfy the above requirements.

The present inventors have been conducting intensive research to solve the above-mentioned problems, and found that certain macromolecules are secreted on the surface and internal organs of fish and seaweed, and this is the cause of resistance from water and swallowing of food etc. Focusing on the fact that it plays a significant role in reducing friction, we found that by incorporating a linear polymer into the polymer gel, a hydrogel with even lower friction could be obtained. As a result of further research, the present invention was completed.

That is, the present invention relates to a low-friction hydrogel in which a linear polymer is mixed or graft-polymerized with a polymer gel.

The present invention also relates to the low friction hydrogel, wherein the linear polymer is graft-polymerized on the surface of the polymer gel.

Further, the present invention relates to the above low friction hydrogel, wherein the monomer constituting the polymer gel and the monomer constituting the linear polymer are the same monomer.

Further, the present invention relates to the low-friction hydrogel described above, wherein the friction coefficient is 0.01 or less.

Furthermore, the present invention provides a low friction hydrogel having a linear polymer content based on the total weight of the hydrogel.

The low-friction hydrogel is characterized in that the content is 2 to 300% by weight. Further, the present invention relates to the above low friction hydrogel, wherein the polymer gel is an ionic gel.

Further, the present invention relates to the low friction hide gel, Related to use.

The present invention also relates to a method for producing a low-friction hydrogel, comprising mixing a polymer forming a polymer or a monomer forming a polymer gel with a linear polymer or a monomer forming a linear polymer. And / or graft polymerization.

Furthermore, the present invention relates to the above method, wherein a linear polymer is mixed with a polymer gel, and the linear polymer chain is post-polymerized.

Further, the present invention provides that the polymer gel contains a linear polymer by mixing and polymerizing a monomer that forms one or more linear polymers in the polymer gel. The present invention relates to the above method.

Further, the present invention is characterized in that a linear polymer is mixed with one or more kinds of monomers forming a polymer gel and polymerized, so that the polymer gel contains the linear polymer. To the method.

The present invention also provides a polymer gel by mixing and polymerizing one or more monomers that form a polymer gel with one or more monomers that form a linear polymer. The method according to the above-mentioned, characterized in that a linear polymer is grafted.

Further, the present invention relates to the above low friction hydrogel, wherein the monomer forming the polymer gel and the monomer forming the linear polymer are the same type of monomer.

The present invention also relates to a method for producing a low-friction hydrogel, wherein the method comprises polymerizing a monomer forming a polymer gel on a hydrophobic substrate. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the results of the rotational speed dependence of the frictional force of a 2-acrylamide-2-methylpropanesulfonic acid (AMP S) gel on a glass plate.

FIG. 2 shows the results of the load dependence of the frictional force of the AMPS gel at a speed of 0.01 rad / s.

FIG. 3 shows the results of the coefficient of friction of a dimethyl acrylamide (DAMM) gel, an AMPS gel, and a polyvinyl alcohol (PVA) gel against a glass plate. FIG. 4 shows the results of the coefficient of friction of the DAMM gel and the AMPS gel against the glass plate.

BEST MODE FOR CARRYING OUT THE INVENTION

The monomer constituting the polymer gel used in the present invention is not limited as long as it is a monomer that forms a hydrogel having a three-dimensional network structure. Derivatives, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide methacrylamide and their derivatives, styrene sulfonic acid, vinyl sulfonic acid, vinyl phosphoric acid, vinyl pyridine And trimethylvinylpyridinium hydrochloride, 3-acryloylaminobutyryl trimethylammonium hydrochloride, 3-dimethylmethacryloyl mouth xishethylammonium propanesulfonic acid, and the like. Preferred are acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, acrylic acid, styrenesulfonic acid and the like.

Crosslinking agents that crosslink these monomers include N, N, -methylenebisacrylamide, ethylene glycol dimethacrylate, divinylbenzene, and the like.

As the monomer for forming the linear polymer used in the present invention, the above-mentioned two or three components of the above-mentioned monomers can be used, but the same type of monomer as the monomer constituting the above-mentioned polymer gel can be used. One can also be used.

In addition to the above-mentioned polymer gel, polysaccharide gels such as dielan gel, carrageenan gel, agarose gel, carboxymethylcellulose gel, protein gels such as gelatin and collagen, nucleic acid gels such as DNA and RNA, Polymer gels such as polyvinyl alcohol, polyglutamic acid, polyethyleneimine, and freeze-thaw gels can also be used.

The content of the linear polymer relative to the total weight of the low friction hydrogel is preferably 2 to 300% by weight, particularly preferably 5 to 100% by weight from the viewpoint of the effect of reducing the frictional force.

The low-friction hydrogel of the present invention includes (1) a low-friction hydrogel in which a linear polymer is mixed with a polymer gel, or (2) a linear polymer in a polymer gel. There is a polymerized low friction hydrogel.

The method for producing a hydrogel according to the above (1), that is, a linear polymer is added to the polymer gel. Any method can be used to produce a hydrogel in which the polymer is mixed, as long as the method can mix a linear polymer with the polymer gel. Typically, the following method is used. No.

a. Physically mix the linear polymer with the polymer gel.

b. After the formation of the polymer gel, the polymer gel is sufficiently immersed in a monomer solution that forms a linear polymer, and the monomers are diffused in the gel, and then the monomers are polymerized.

c When a polymer gel is formed, a linear polymer is mixed with monomers and other materials and polymerized to form a gel.

On the other hand, the method for producing a hydrogel according to the above (2), that is, a method for producing a hydrogel in which a linear polymer is graft-polymerized to a polymer gel, includes grafting a linear polymer to a polymer gel. Any method may be used as long as it is a polymerization method, but typically the following method is used.

d. Mix the formed polymer gel with the linear polymer and post-polymerize the graft.

e. One or more of the monomers that form the polymer gel and one or more of the monomers that form the linear polymer are mixed and polymerized to form a polymer gel. Graft the chain polymer.

f. Polymerization of polymer gel sandwiched between hydrophobic substrates.

In particular, the above method f. Is a novel gel synthesis method developed by the present inventors independently (J. Phys. ChemB, 103, 6069-6074 (1999), Biomacromolecules, 1, 162-167 (2000), Proceedings of the Society of Polymer Science, Japan, Vol. 48, No. 2, 2603-2604 (1999), Proceedings of the Society of Polymer Science, Japan, Vol. 49, No. 3, 3689-3692 (2000)). Instead of the conventional polymerization of gel on a hydrophilic substrate such as a glass substrate, a hydrophobic substrate such as Teflon plate, polypropylene, polyethylene, or polystyrene is used. As a result, a concentration gradient of the hydrophilic monomer solution is generated, the cross-linking density of the gel becomes low, and as a result, a gel having a graft chain on the surface is formed. This method is particularly suitable because a desired gel can be easily formed only with a hydrophobic substrate without using another reagent or the like in one step.

Since the polymer gel having a linear polymer obtained by each of the above methods contains a hydrophilic polymer chain in the gel or on the surface, the water content of the gel is further increased, The hydrous gel or the polymer chain hydrous on the surface acts as a lubricating layer at the interface with the solid, so that a low-friction polymer hydrogel can be obtained. Furthermore, when the low-friction hydrogel is an ionic gel, and a low-friction hide-mouth gel using an ionic linear polymer chain is applied to the solid surface, an electrostatic A repulsive force is generated, and a thicker water layer is formed at the friction interface as compared with the neutral gel, so that the best friction effect can be obtained.

In order to obtain a sufficient low friction effect, the hydrogel according to the present invention preferably contains a large amount of water, and the water content is preferably 50% by weight or more, particularly preferably 100% by weight or more. is there.

Further, the friction coefficient of the obtained gel at the mouth is preferably 0.01 or less, particularly preferably 0.005 or less.

The form of the hydrogel according to the present invention may be any form as long as it includes a linear polymer chain in the polymer gel or on the surface of the polymer gel. Preferably, the polymer has a linear polymer on the surface of the gel, and more preferably has a polymer chain graft-polymerized on the surface.

Example

Hereinafter, the low friction hydrogel of the present invention will be described in more detail with reference to Examples, Comparative Examples, and Test Examples, but these do not limit the present invention at all. (Example 1)

2-Acrylamido acid A solution containing 20 g of 2-methylpropanesulfonic acid (A MPS) in 100 ml of methylene bisacrylamide 8% as a cross-linking agent, 0.1% hyketoglutaric acid as a photosensitizer, and a pre-synthesized molecular weight of 250,000 An AMPS gel containing linear polymers was prepared on a glass plate, containing 4 g of poly (AMPS) and irradiating with 400 W ultraviolet light.

(Example 2)

An AMPS gel containing a linear polymer was prepared in the same manner as in Example 1 except that 8 g of poly (AMPS) having a molecular weight of 250,000 in Example 1 was contained instead of 4 g. (Comparative Example 1)

Except for not containing poly (AMPS) with a molecular weight of 250,000, A PAMPS gel containing no linear polymer was prepared.

-The gels of Examples 1, 2 and Comparative Example 1, which were cut into a cube with sides of 2 cm, were placed on a glass plate and the stress was measured when the glass plate was rotated at various speeds. The friction force was measured in water. The results are shown in Table 1. Table 2 shows the results of the frictional force measured by placing the gels of Example 2 and Comparative Example 1 on the same gel, but not on the glass plate. Table 1 Between gel and glass

(Example 3)

Using dimethyl acrylamide (DMAA) instead of AMPS used in Example 1, and 2 g of linear poly (DMA A) having a molecular weight of 120,000 instead of poly (AMP S) having a molecular weight of 250,000, In the same manner as in Example 1, a DMAA gel containing a linear polymer was synthesized.

(Comparative Example 2)

Example 3 was repeated except that it did not contain linear poly (DMAA) having a molecular weight of 120,000. In the same manner as in Example 3, a DMAA gel containing no linear polymer was prepared.

Table 3 shows the measurement results of the frictional force between the gel and the glass in the same manner as in Example 1 using the gels of Example 3 and Comparative Example 2.

Table 3 Gel glass

(Example 4)

In the synthesis of the ordinary AMPS gel of Comparative Example 1, polymerization was performed not on a glass plate but on a resin acryl resin plate to prepare a graft gel having a free terminal poly (AMPS) chain on the gel surface. The obtained gel was swollen in water, and the frictional force between gel and glass was measured in the same manner as in Example 1. Table 4 shows the results of comparison with Comparative Example 1.

1 Gel-glass

(Example 5)

When 10 g of the PAMPS gel synthesized in Comparative Example 1 was pre-synthesized and left at room temperature for one week in 20 O ml of an aqueous solution containing 4 g of poly (D MAA) having a molecular weight of 100,000, poly (D MAA) A PAMPS gel containing 0.6 g was obtained.

After equilibrium swelling of the gel thus obtained with pure water, the frictional force was measured using a viscoelasticity tester (ARES, Rheometric Scientific, Inc.). The power had dropped to 1-2. (Example 6)

By heating 100 ml of an aqueous solution containing 3 g of poly (acrylamide) having a molecular weight of 120,000, 7 g of polyvinyl alcohol having a molecular weight of 80,000, and 2 g of ethylene glycol glycidyl ether as a crosslinking agent at 70 ° C for 24 hours, A polyvinyl alcohol gel containing poly (acrylamide) was obtained. The gel was cut into 1 cm x 1 cm x 1 cm cubes, and the friction force was measured by the method described in Example 5, where the value was 15% of that without poly (acrylamide). (Test Example 1)

0.5 g of methylene bisacrylamide as a cross-linking agent and 0.5 lg of ketoglutaric acid as a photosensitizer are added to 100 ml of an aqueous solution containing 10 g of AMP S, and 400 W UV irradiation is performed to create an AMPS gel on a glass plate. I do. The resulting gel is immersed in 100 ml of an aqueous solution containing 4 g AMPS monomer for one week, and the monomer is diffused inside.Then, the polymer is polymerized inside by irradiating with 400 W ultraviolet light, and the linear polymer chain is formed. A gel containing was prepared.

Separately, when polymerizing an AMPS gel with the same composition as the above-mentioned gel, it was polymerized on polystyrene instead of a glass plate to create a gel having poly (AMPS) graft chains on the surface.

FIG. 1 shows the results of measuring the frictional force of the gel on the glass plate by the method described in Example 5.

As shown in the figure, a normal AMPS gel made of a glass plate has a frictional force on the order of 10 ¹ to 10 ² Nm- ² , whereas a gel containing a linear polymer has a frictional force of 1.0 ° to 10 Nm- ² . - ² Nm ^2, gels having a linear graft chain to create the surface of the polystyrene as the substrate 10 - showed ¹ ~ 10- ³ Nm one ² and smaller frictional force. When calculating the friction coefficient from the values it it ^10-2 to ^10-3, ^10-3 to ^10-4, a 10 ⁴ to ^10-5. In the region where the relative velocity was low, the frictional force decreased by more than two orders of magnitude due to the presence of the linear polymer.

(Test Example 2)

Fig. 2 shows the results of measuring the load dependence of the friction force with the speed fixed at 0.01 rad / s. From the figure, it can be seen that both the gel containing a linear polymer and the gel having a graft chain on its surface have at least an order of magnitude lower frictional force than ordinary gels. It was found that the frictional force was reduced by more than an order of magnitude.

The frictional force of the gel having a graft chain on the surface was greatly reduced, especially in the low speed and low load range.

(Test Example 3)

DMAA gel was prepared on a glass plate by adding 200% UV light to 50% of an aqueous solution containing 7 g of DMAA containing 1% by weight of methylene bisacrylamide as a crosslinking agent and 0.5% by weight of ketoglutaric acid as a photosensitizer. I do. An AMPS gel was prepared in the same manner. On the other hand, 100 ml of an aqueous solution containing 2 g of ethylene glycol diglycidyl ether and 10 g of polyvinyl alcohol is reacted at 80 ° C for 24 hours to perform cross-linking to prepare a polyvinyl alcohol (PVA) gel. Each of the obtained gels is immersed in a 1.0 M DMAA monomer aqueous solution or a 1.0 M AMPS monomer aqueous solution for one week, and after the monomer is diffused inside, it is irradiated with 400 W ultraviolet light to polymerize the polymer inside. As a result, a gel containing a linear polymer chain was prepared. Figure 3 · shows the results of measuring the respective friction coefficients.

The figure shows the results of gels containing poly (DMAA) or poly (AMPS) in DMAA gel, and the figures below show poly (AMPS) in polyvinyl alcohol (PVA) gel and AMPS gel. Gel results.

DMAA gels contain linear polymer chains to reduce the coefficient of friction to less than 1 / 10th of the maximum, and those containing poly (AMPS) to AMPS gels less than 1/100 of the PVA. The gel containing poly (AMPS) reduced the coefficient of friction to less than 1 in 1000.

(Test Example 4)

When synthesizing the gels of DMA A and AMP S in Test Example 3, polymerization was performed not by using a glass plate but by a Teflon plate, and a gel having a free terminal graft chain on the gel surface was prepared. Figure 4 shows the results of measuring the respective friction coefficients.

In the same figure, DMA A is a gel polymerized between glass plates, DMAAgraft is a polymer polymerized between Teflon plates, and a gel with a graft chain on the surface, and PAMPS is a glass. An AMP S gel polymerized by sandwiching between Teflon plates and PAMPSgraft indicate an AMP S gel polymerized by sandwiching between Teflon plates and having a graft chain on the surface.

In DMAA gel by free end graft chains present on the surface, the friction coefficient is 1, AMP S gel up to 10, 1 next to the maximum 1000 minutes, resulting in far that the friction coefficient of 6 x 1 0 one ⁵ It showed an unusually low value.

Industrial applicability

ADVANTAGE OF THE INVENTION According to this invention, the material of low friction as never before can be manufactured.

Claims

Claims. A low-friction hydrogel obtained by mixing a linear polymer with a polymer gel or by graft polymerization. The low friction hydrogel according to claim 1, wherein the linear polymer is graft-polymerized on the surface of the polymer gel. 3. The gel of claim 1, wherein the monomer constituting the polymer gel and the monomer constituting the linear polymer are the same type of monomer. The low-friction hydrogel according to any one of claims 1 to 3, wherein the coefficient of friction is 0.01 or less. The low-friction hydrogel according to any one of claims 1 to 4, wherein the content of the linear polymer is 2 to 300% by weight based on the total weight of the low-friction hydrogel. The low friction hydrogel according to any one of claims 1 to 5, wherein the polymer gel is an ionic gel. Use of the low-friction hide mouth gel according to claim 6 on solid and living tissue surfaces. A method for producing a low-friction hydrogel, comprising mixing a polymer forming a polymer or a monomer forming a polymer with a linear polymer or a monomer forming a linear polymer, and / or grafting. The above method, which comprises polymerizing. 9. The method according to claim 8, wherein a linear polymer is mixed with the polymer gel, and the linear polymer chain is subjected to post-polymerization grafting. 0. The polymer gel contains one or more monomers that form a linear polymer, and is polymerized to contain the linear polymer. The method of claim 8, wherein:

1. A linear polymer is mixed with one or more kinds of monomers that form a polymer gel and polymerized so that the polymer gel contains the linear polymer. Item 9. The method according to Item 8.

2. One or more of the monomers that form the polymer gel are mixed with one or more of the monomers that form the linear polymer, and polymerized to form a polymer gel. 9. The method according to claim 8, wherein a straight-chain polymer is grafted.

3. The low friction hydrogel according to any one of claims 8 to 12, wherein the monomer forming the polymer gel and the monomer forming the linear polymer are the same type of monomer. .

4. A method for producing a low friction hydrogel, comprising polymerizing a monomer that forms a polymer gel on a hydrophobic substrate.