JP2539384B2 - Materials for soft contact lenses - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a contact lens material, and more particularly to a soft and substantially non-hydrated contact lens material.

[Conventional technology]

Conventionally, various polymers have been proposed as materials for contact lenses, and they are roughly classified into soft materials and hard materials, but it is well known that soft materials are preferable in order to obtain contact lenses with a good wearing feeling. .

As such a soft material, there is a hydrous contact lens material that absorbs water, swells, and is softened. Particularly, a high hydrous contact lens that absorbs a large amount of water has high oxygen permeability, and thus is actively studied. Has been done.

However, water-containing contact lenses have the drawbacks that complicated operations such as disinfection are required because bacteria and mold may propagate, and water-containing contact lenses have poor mechanical strength.

On the other hand, contact lenses made of silicone rubber have very high oxygen permeability and do not contain water, so they do not have the drawbacks of water-containing contact lenses, but they have the drawback that the surface of the contact lens is extremely water-repellent, which is a serious problem. It has also been reported to cause various obstacles.

Further, a contact lens composed of a copolymer of alkyl methacrylate and alkyl acrylate has also been proposed, and in particular, a contact lens mainly containing butyl methacrylate and butyl acrylate has been put into practical use,
This was not preferable because the oxygen permeability was not so high.

[Problems to be solved by the invention]

INDUSTRIAL APPLICABILITY The present invention does not have the drawbacks of the soft contact lens as described above, that is, since it is substantially water-free, it does not require disinfection operation, is excellent in hydrophilicity, and has high oxygen permeability. Is provided.

[Means for solving problems]

That is, the present invention provides (a) 10 to 30 parts by weight of tris (trimethylsiloxy) represented by the formula (I) per 100 parts by weight of the total amount of (a), (b) and (c) below. Silylpropyl methacrylate (hereinafter referred to as "A component"), (B) 5 to 20 parts by weight of a (meth) acrylic acid ester of a fluoroalkyl alcohol having 2 to 8 carbon atoms (hereinafter referred to as "B
Component)) and (c) 40 to 80 parts by weight of an acrylate ester of a linear alkanol having 4 to 8 carbon atoms (hereinafter referred to as “component C”), The present invention relates to a material for soft contact lenses which is substantially free of water.

[Structure of Invention]

The component A used in the present invention is a kind of siloxanylalkyl methacrylate, but among them, the component A is easy to synthesize and is suitable for obtaining a contact lens having high oxygen permeability. It is a well-matched monomer.

On the other hand, the component B of the present invention is a monomer exhibiting extremely high oxygen permeability due to its synergistic effect when it is copolymerized with the component A. Examples thereof include 2,2,2-trifluoroethyl methacrylate, 1,1-dimethyl-2,2,3,3-tetrafluoropropyl methacrylate, 1,1-dimethyl-2,2,3,
4,4,4-hexafluorobutyl methacrylate, 2,2,3,
4,4,4-hexafluorobutyl methacrylate, 2,2,3,3
-Tetrafluoropropyl methacrylate, hexafluoroisopropyl methacrylate and the like,
Among them, 2,2,2-trifluoroethyl methacrylate is preferable in that a material having high resilience can be obtained.

In the present invention, the C component is further used,
Component C is a monomer for obtaining a material which is non-hydrous, flexible and elastic. In addition to this, the component C is preferably used because it does not impair the oxygen permeability of the components A and B. Examples of the C component include n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, and n-octyl acrylate. Among them, n is a point that gives a polymer having excellent elasticity. -Butyl acrylate is most preferred.

The copolymerization ratio of A component, B component and C component is 10 to 30 parts by weight with respect to 100 parts by weight of the total amount of the three components,
The B component is preferably 5 to 20 parts by weight, and the C component is preferably 40 to 80 parts by weight. This is because if the amounts of the A component and the B component are too large, the contact lens material becomes hard and loses elasticity, whereas if it is too small, the oxygen permeability becomes low. Furthermore, the ratio of the A component and the B component is approximately the same in order to obtain the above synergistic effect.
It is preferably 4: 1 to 1: 2.

In the present invention, the components A, B and C are the main components, but it is of course possible to copolymerize various monomers other than the above. Examples include hydroxyl group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, and N-vinylpyrrolidone for the purpose of imparting hydrophilicity. In order to copolymerize hydrophilic monomers such as various N-vinyl lactams or stabilize the shape of contact lenses, for example, ethylene glycol di (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, diethylene glycol. So-called "crosslinking agents" such as di (meth) acrylate, triethyleneglycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, etc. To It is also possible to polymerize. Further, silicon-containing (meth) acrylates other than the A component such as trimethylsilylpropyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, nonyl. An alkyl (meth) acrylate other than the C component such as (meth) acrylate, dodecyl (meth) acrylate, cyclohexyl (meth) acrylate may be copolymerized. Further, if necessary, a polymerizable dye, a reactive dye, a vat dye,
It is also possible to blend or add a dye such as a diazo dye and copolymerize.

In the present invention, various optional components can be blended as described above, but in order to obtain a contact lens which can omit operations such as disinfection when it is used as a contact lens, it must be substantially free of water. In particular, the water content is preferably 3% or less, more preferably 1.5% or less. Also, because it can be worn on the eye for a long time, the oxygen permeability coefficient is The above is preferable, and in order to maintain a suitable wearing state as a soft contact lens, it is preferable that the elongation rate is 100% or more at a thickness of 0.3 mm or less, and the strength index is sufficient to withstand harsh handling. Is preferably 30 or more.

Next, the method for measuring the punch-out strength, elongation and strength index in the present invention will be described.

FIG. 1 is a sectional view showing a state in which a sample film is mounted on a sample stand of a measuring instrument. The sample film 1 is fixed by two rubber-shaped O-rings 2 and 3, and a spherical indenter 5 fixed to the tip of a push rod 4 having a tapered lower portion above the center of the O-ring. The push rod 4 is attached to the tip of a load cell (not shown), and the load cell is connected to a power source, an amplifier, a recorder (neither is shown), etc. That is, the force received by the film 1) and the time (since the moving speed of the indenter 5 is constant, it can be easily converted to the moving speed of the indenter 5) can be recorded. When the measurement is started, the push rod 4 moves downward at a constant speed,
Press the sample film 1. The sample film gradually expands, but eventually breaks without being able to withstand the force of the indenter 5. Second
The drawing is a cross-sectional view showing the state of the sample film immediately before breaking, and FIG. 3 shows an example of the chart of the recorder after the measurement. In FIG. 3, the vertical axis represents intensity, the horizontal axis represents time, and one scale on the horizontal axis is 10 seconds. The force applied to the film 1 at the moment the film breaks is the puncture strength, which can be read directly from the chart. On the other hand, the elongation is calculated from the inner diameter of the O-ring before the measurement, that is, 1 in FIG. 1 and the distance between the films immediately before breaking, that is, l2 in FIG.

It should be noted that l2 is the distance l3 moved from the contact of the indenter 5 to the film 1 until the film 1 is broken (this is shown in FIG. 3).
It is a value obtained by multiplying the moving speed of the load cell by the time of l4)
From 1, it can be calculated by the following formula.

(L2 / 2) ² = (1/2) ² + (l3) ² Further, the strength index E is calculated from the punch-out strength G, the elongation S and the film thickness T by the following formula (each unit is in parentheses). Shown).

In obtaining the copolymer of the present invention, a known polymerization method, preferably a bulk polymerization method, is used, and a method of polymerizing with a UV ray or heat is preferable. Further, a polymerization initiator can also be used, and as such a polymerization initiator, for example, azobis compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile, and peroxides such as benzoyl peroxide are preferably used. . And at that time, the polymerization is generally carried out at a temperature of about 10 ° C. to about 90 ° C., but after the polymerization is started at such a temperature, the temperature is raised stepwise or continuously to complete the polymerization. In this case, the final temperature is preferably 90 ° C to 150 ° C.

In producing the copolymer used in the present invention, a well-known method such as a method of polymerizing in a molding die, a method of spin casting polymerization, a method of molding after polymerization and the like can be used. Above all, since the contact lens material of the present invention is soft, a method of polymerizing in the mold or a method of spin casting polymerization is preferable.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Examples 1 to 8) Various formulations as shown in Table 1 were performed. That is, a fluororesin gasket is sandwiched with polyester films from both sides, and the monomer and polymerization initiator are mixed and dissolved in a mold in which the outside is sandwiched with glass plates (monomer mixed solution), and hot air circulation drying is performed. 24 hours at 50 ℃ in the vessel, then 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃ and 110 ℃
Were sequentially polymerized for 2 hours to obtain a sample film.

Then, the obtained film was punched into a punch having a diameter of about 14 mm and each physical property was measured. The measuring methods and units of each physical property in Table 1 are as follows.

Moisture content ・ Measurement temperature: 20 ℃ ・ Unit: 0% ・ Calculation formula Equilibrium water content film weight = W1 Dry film weight = W2 Oxygen permeability coefficient ・ Measurement temperature: 35 ℃ ・ Measuring instrument: A Kaken film oxygen permeability meter (Rika Seiki Co., Ltd.) is used.

Punching strength-Measuring temperature: Room temperature-Unit: g-Measuring method Using an Instron type compression tester, a 1/16 inch diameter pressing needle (indenter) was applied to the center of the film, and the load at break was measured. .

Elongation rate ・ Measurement temperature: Room temperature ・ Unit:% ・ Measurement device Same as punching load (simultaneous measurement). The amount of elongation up to break is calculated as a percentage.

(Comparative Example 1) A thickness of 229 was obtained in the same manner as in Example 1 except that t-butyl acrylate was used instead of n-butyl acrylate.
A sample film having a diameter of 14 μm and a diameter of 14 mm was prepared. Next,
Although it was attempted to measure the elongation of the sample film in the same manner as in Example 1, the sample film was hard and cracked, and the elongation could not be measured.

From this fact, t-
It can be seen that the soft contact lens intended by the present invention cannot be obtained by using -butyl acrylate.

(Comparative Example 2) A thickness of 194 was obtained in the same manner as in Example 3 except that t-butyl acrylate was used instead of n-butyl acrylate.
A sample film having a diameter of 14 μm and a diameter of 14 mm was prepared. Next,
Although it was attempted to measure the elongation of the sample film in the same manner as in Example 3, the sample film was hard and cracked, and the elongation could not be measured.

From this fact, t-
It can be seen that the soft contact lens intended by the present invention cannot be obtained by using -butyl acrylate.

(Comparative Example 3) Soft contact lens containing butyl methacrylate and butyl acrylate as main components (trade name "Sofina")
Ricky Contact Lens Laboratories) was measured in the same manner as in the example. Appearance: transparent, water content: 0.28, oxygen permeability coefficient: 30.0 (thickness: 220 μm), punch-through strength: 232, elongation: 37, strength The index was 20.

It can be seen that the contact lens material of the present invention has a very high strength index.

〔The invention's effect〕

The soft contact lens using the contact lens material of the present invention has the following features.

(1) Due to its high oxygen permeability, the burden on the cornea of the eye is small and it can be worn for a long time.

(2) Because it is flexible, it feels good to wear.

(3) Since it is substantially non-hydrated, there is no concern that it will be contaminated with bacteria or mold.

(4) Since the strength index is larger than that of the conventional non-hydrated soft contact lens material, the risk of breakage is small in handling.

[Brief description of drawings]

The drawing is a principle view of the method for measuring the punch-out strength and the elongation, FIG. 1 is a cross-sectional view showing a state in which the sample film is mounted on the sample stand of the measuring instrument, and FIG. It is sectional drawing which shows a state. FIG. 3 is an example of a chart obtained as a result of measurement.

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-58-194014 (JP, A) JP-A-59-28127 (JP, A) JP-A-62-38418 (JP, A) JP-A-62- 38419 (JP, A) JP 62-127824 (JP, A) JP 50-87184 (JP, A) JP 58-132725 (JP, A)

Claims (3)

(57) [Claims] 1. A total of 100 parts by weight of the following (a), (b) and (c): 10 to 30 parts by weight of (a), 5 to 20 parts by weight.
A substantially non-hydrated soft contact lens material, characterized in that (b) parts by weight and (c) 40 to 80 parts by weight are used. (A) Tris (trimethylsiloxy) silylpropyl methacrylate represented by the formula (I) (B) (Meth) acrylic acid ester of fluoroalkyl alcohol having 2 to 8 carbon atoms (c) Acrylic ester of linear alkanol having 4 to 8 carbon atoms. 2. The soft contact lens material according to claim 1, wherein the acrylic acid ester of a linear alkanol having 4 to 8 carbon atoms is n-butyl acrylate. 3. A water content of 3% or less and an oxygen permeability coefficient The soft contact lens according to any one of claims 1 and 2, wherein the elongation is 100% or more and the strength index is 30 or more at a thickness of 0.3 mm or less. Materials.