JP2876013B2 - Oxygen permeable molding - Google Patents

Description

The present invention relates to a molded article that is transparent and has excellent oxygen permeability.

[Conventional technology]

In recent years, contact lenses have become widespread as a means of correcting visual acuity. However, if the oxygen permeability of the contact lens is low, it causes an oxygen deficiency disorder of the cornea. Therefore, a transparent material excellent in oxygen permeability is required.

In response to such a demand, a molded product of a dimethylsiloxane oligomer having a polymerizable group at a terminal or a random copolymer containing siloxanyl methacrylate and methyl methacrylate as main components is used for a hard contact lens.

[Problems to be solved by the invention]

However, with this random copolymer, it is necessary to considerably increase the content of the silicon-containing component in order to have a sufficient oxygen permeability, so that it becomes difficult to form a film, a lens, and the like, and furthermore, the tear strength and The surface hardness had to be relatively low, making it impractical. Therefore, since the content of the silicon-containing component is actually reduced in consideration of the moldability, there is a problem that a material having sufficient oxygen permeability cannot be obtained.

An object of the present invention is to have oxygen permeability high enough to be used as an oxygen permeable film in at least one direction, and to have strength, hardness and transparency to such an extent that it does not hinder molding and use as a contact lens or the like. An object of the present invention is to provide an oxygen-permeable molded article having excellent properties.

[Means for solving the problem]

That is, the present invention comprises a block or graft copolymer comprising polydimethylsiloxane as one component and a copolymer of methyl methacrylate and a functional monomer represented by the following formula (I) as the other component. The fiber bundle is obtained by impregnating the fiber bundle with a monomer composition containing methyl methacrylate, a silicon-containing methacrylate ester and a functional monomer represented by the following formula (I) as main components, and polymerizing the fiber bundle. It is an oxygen-permeable molded article excellent in strength and hardness.

[In the formula (I), R represents -H or -CH _3, X is -
H, CH _{2 n} OH, Or _{-.. (CH 2 n NR} 2 '( where R' is the CH ₂ showing the _m CH ₃₎ indicates, n and m in the present invention represents an integer of 0 to 5, one component polydimethylsiloxane And a block or graft copolymer (hereinafter, referred to as a copolymer (a)) having a copolymer of methyl methacrylate and a functional monomer represented by the formula (I) as the other component, has a number average molecular weight of: If the number average molecular weight of the copolymer (a) is less than 10,000, shaping into fibers tends to be difficult. When the copolymer (a) is a graft copolymer, polydimethylsiloxane may be a main chain component or a side chain component.

The content of polydimethylsiloxane, which is one component of the copolymer (a), is preferably 15% by weight or more and less than 85% by weight. If it is less than 15% by weight, the oxygen permeability tends to be insufficient, and if it is more than 85% by weight, the surface hardness and the tear strength tend to decrease. The number average molecular weight of the polydimethylsiloxane in the copolymer (a) is 700 to 300,0.
It is preferably 00. If it is less than 700, the resulting molded article tends to have insufficient oxygen permeability, and if it exceeds 300,000, the transparency tends to decrease.

The functional monomer represented by the formula (I) used for the other component of the copolymer (a) may be appropriately selected in consideration of the interaction with the functional monomer used for the monomer composition for impregnation polymerization. This point will be described in detail later. As the functional monomer of formula (I) used herein, (meth) acrylic acid is most preferred. These may be used in combination of two or more. In the copolymer of methyl methacrylate and the functional monomer of (I), the content of the functional monomer is preferably less than 50% by weight. And 0.
1 to 25% by weight is more preferred. If the content is 50% by weight or more, it tends to be difficult to form fibers.

The fiber mainly composed of the copolymer (a) may be composed of only the copolymer (a) or may be a mixture with another polymer. When it is a mixture with another polymer, it is preferable that this polymer has excellent compatibility with the copolymer (a). Such other polymer is preferably methyl methacrylate or a homopolymer of the functional monomer of the formula (I) or a copolymer containing these monomers as a main component. The content of the copolymer (a) in this mixture is preferably at least 20% by weight. If this is less than 20% by weight, the oxygen permeability tends to decrease.

The molded article of the present invention is obtained by forming a fiber using the copolymer (a) containing polydimethylsiloxane having one of the above-mentioned excellent oxygen permeability as a component, and integrating the fibers in a bundle. Excellent oxygen permeability in the axial direction. As the thickness of the fibers, those having the dimensions of ordinary fibers can be used, but the diameter is preferably about 200 μm or less. Further, as described above, the fiber may be a fiber of a homogeneous mixture of the copolymer (a) and another copolymer. Further, a core-sheath conjugate fiber in which the copolymer (a) or a component containing the copolymer as a main component is used as a core and another polymer is used as a sheath may be used. A sea-island fiber may be used, in which the above-mentioned components are made into islands and the other polymer is made into sea. Each of these fibers can be obtained by a usual method.

The size of the fiber bundle when bundling the fibers is appropriately selected depending on the application. For example, when the fibers are used for applications such as contact lenses and intraocular lenses, it is preferable to bundle the fibers so as to have a diameter of about 5 to 15 mm.

Next, the fiber bundle is impregnated with a monomer composition containing methyl methacrylate, a silicon-containing methacrylate ester and a functional monomer represented by the formula (I) as main components, and polymerized.

As the silicon-containing methacrylate used in the monomer composition for impregnation polymerization, any may be used, but it is preferable to use a compound represented by the following formula (II).

(Wherein, m is an integer of 2 to 5, X is each independently a methyl group or Wherein n represents an integer of 0 to 30. It is desirable that the functional monomer of the formula (I) used in the monomer composition for impregnation polymerization has a large interaction with the functional monomer of the formula (I) used in the copolymer (a). The interaction referred to here is a dipole of polar functional groups.
It means physical interaction such as intermolecular force and hydrogen bond caused by dipole effect and chemical interaction accompanied by reaction between functional groups, and the functionality of the formula (I) capable of exhibiting such an action Any monomer is effective.

Illustrating the relationship between the monomer of the formula (I) of the copolymer (a) and the monomer of the formula (I) for impregnation polymerization, Are preferred.

Among these, particularly when (meth) acrylic acid is used as the monomer of the formula (I) for forming the copolymer (a), the monomer of the formula (I) for the impregnation polymerization includes:
Most preferably, it is glycidyl methacrylate.

In the molded article of the present invention, particularly, such a functional monomer is used for both the fiber and the monomer for impregnation polymerization. can get.

The composition ratio of methyl methacrylate, silicon-containing methacrylate ester and the functional monomer of the formula (I), which are the main components of the monomer composition for impregnation polymerization, may be set arbitrarily so that the molded product exhibits desired properties. Although it is good, it is particularly preferable to set the same refractive index as that of the fiber.

Along with the above-mentioned monomer composition, a polyfunctional methacrylate such as ethylene glycol dimethacrylate or allyl methacrylate as a crosslinkable component can be contained for the purpose of improving mechanical strength and surface hardness. Further, for the purpose of adjusting the refractive index, a fluoromethacrylate (low refractive index) such as 1,1,1-trifluoroethyl methacrylate, phenyl methacrylate (high refractive index) and the like can be contained.

By performing bulk polymerization or the like in a state where the fiber bundle is impregnated with the above monomer mixture or the like, a rod-shaped molded product can be obtained. It is desirable that the fiber bundle in the molded product is 65% by weight or more from the viewpoint of obtaining a molded product having high oxygen permeability.

The rod-shaped molded product is cut perpendicular to the fiber axis direction to obtain a button-shaped or film-shaped molded product, and the molded product is subjected to desired processing such as cutting or compression or vacuum forming, polishing, or the like to obtain a contact lens. , An intraocular lens can be formed.

The molded article of the present invention has a feature that oxygen permeability in the thickness direction, that is, the fiber axis direction is high. This is because the copolymer (a) was phase-separated into a domain composed of polydimethylsiloxane and a domain composed of other components in the molded article, and these domains were oriented in the fiber axis direction by fiberization and were narrowly connected. This is because it has a structure. Therefore, when a film-shaped or button-shaped molded product is obtained as described above, a structure in which domains of polydimethylsiloxane are communicated substantially from one surface to the other surface is provided, and oxygen permeability in the thickness direction is increased. It is. The size of the microdomain is several nm to several tens of nm, which is smaller than the wavelength of visible light, so that it becomes transparent.

Further, in the molded article of the present invention, since the functional monomer of the formula (I) is used, the molded article itself is more excellent in strength and hardness.

As described above, the molded product of the present invention is suitable as a material for contact lenses and intraocular lenses because of its high oxygen permeability, but the size of the fiber bundle is further appropriately selected. When a large bundle is formed by adhering a large number of fiber bundles or by making a large number of the bundles, and sliced, it is very useful for use as a membrane or container having excellent strength, hardness and oxygen permeability.

〔Example〕

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

Example 1 100 g of polydimethylsiloxane having a methacryloyloxy group at one end (molecular weight: 3,000), 99 g of methyl methacrylate, and 1 g of methacrylic acid were dissolved in 400 ml of toluene, and 1.0 g of benzoyl peroxide was added. 6 at ℃
Allowed to react for hours. The liquid after the reaction was dropped into a mixed solvent of methanol / hexane (2/1) to obtain a white graft copolymer (80% yield). GPC measurement of this copolymer showed M _n = 53,000 and M _w = 191,000.

Using a nozzle having a diameter of 0.3 mm, the graft copolymer was spun at a spinning temperature of 220 ° C., a discharge linear speed of 120 cm / min, and a winding speed of 60 mm.
The fiber was spun at 00 cm / min to obtain a fiber having a fiber diameter of about 50 μm.

About 60,000 of these fibers were bundled and packed in a tetrafluoroethylene tube having a length of 5 cm and a diameter of 1.5 cm with both ends opened. Separately, a monomer mixture of methyl methacrylate, tris (trimethylsiloxy) -γ-methacryloyloxypropylsilane, glycidyl methacrylate, 1,1,1-trifluoroethyl methacrylate, and ethylene glycol dimethacrylate ( 36/40/3/20 by mixing ratio weight
/ 1) with azobisisobutyronitrile per monomer 0.2
A test tube containing the weight percent was prepared, and after repeated degassing, the fiber bundle was put therein and impregnated with the monomer mixture. 6 hours at 40 ° C, 6 hours at 50 ° C
Polymerization was conducted at 60, 70, 80, 90 and 100 ° C. for 2 hours each to obtain a rod-shaped molded product. The polydimethylsiloxane content of this molded product was 35% by weight.

This rod-shaped product is sliced in the direction perpendicular to the fiber axis, and both sides are polished to obtain a transparent film with a thickness of 0.2 mm, and the oxygen transmission coefficient in the thickness direction (fiber axis direction) of this film is measured. 180 × 10 ^-10 cm ³ (STP) cm / cm ²
・ Sec ・ cmHg

On the other hand, the rod-shaped molded product is cut in a direction parallel to the fiber axis and polished on both sides to obtain a film having a thickness of 0.2 mm. The oxygen transmission coefficient in the thickness direction of the film (direction perpendicular to the fiber axis) When measured, 10 × 10 ⁻¹⁰ cm ³ (STP) · cm / cm ²
・ Sec ・ cmHg

That is, the oxygen transmission coefficient in the fiber axis direction was very high. Further, the Shore D hardness was 72, and the strength was high enough to withstand cutting.

Example 2 A molded product was obtained in the same manner as in Example 1 except that the fiber obtained in Example 1 was replaced with dimethylaminoethyl methacrylate instead of glycidyl methacrylate of the monomer mixture to be impregnated into the fiber bundle. The oxygen permeability coefficient of this molded product in the fiber axis direction is 190 × 10 ⁻¹⁰ cm ³ (STP) · cm / cm ² · sec · cmH
g, the oxygen permeability coefficient in the direction perpendicular to the fiber axis is 15 × 10
^{It was -10} cm ³ (STP) · cm / cm ² · sec · cmHg. Shore D
The hardness was 71, and cutting was sufficiently possible.

Comparative Example 1 In graft copolymerization, polydimethylsiloxane having a methacryloyloxy group at one end (molecular weight: 3,000) 1
A graft copolymer was obtained in the same manner as in Example 1 except that only 100 g of methyl methacrylate and 100 g of methyl methacrylate were used (yield: 85
%, _Mn = 65,000, _Mw = 195,000).

The graft copolymer was made into a fiber bundle in the same manner as in Example 1, and methyl methacrylate, tris (trimethylsiloxy) -γ-methacryloyloxypropylsilane,
Uses a monomer mixture of 1,1-trifluoroethyl methacrylate and ethylene glycol dimethacrylate (mixing ratio by weight of 40/40/20/1) with azobisisobutyronitrile added at 0.2% by weight based on the monomer In the same manner as in Example 1, a rod-shaped molded product was obtained. The polydimethylsiloxane content of this molded product was 36% by weight.

The oxygen permeability coefficient of this molded product was almost the same as that of Example 1, but the Shore D hardness was 67, indicating that the hardness was lower than that of the molded products of Examples 1 and 2 using the functional monomer. .

Example 3 20 mmol of a polydimethylsiloxane-based diol compound having a hydroxyl group at both terminals and having the following structural formula (molecular weight: 10,000): 65 mmol of isobutyric acid and 0.15 mmol of p-toluenesulfonic acid were dissolved in about 400 ml of benzene, and the resulting water was refluxed for 6 hours while being adsorbed and removed by a molecular sheep placed in a cooling tube to obtain both ends. Synthesized a silicon compound isobutyric acid ester.

The solvent was distilled off from the reaction product, washed with a saturated aqueous solution of sodium hydrogencarbonate and then with distilled water, and the oil layer was dried over magnesium sulfate to obtain a colorless, transparent, oily silicon compound having both ends isobutyric acid esterified. Released.

Next, 200 ml of dehydrated and purified tetrahydrofuran (THF) and 30 mmol of diisopropylamine were placed in another reaction vessel, the temperature of the reaction system was cooled to 0 ° C., and 40 ml of a 1.6 M hexane solution of n-butyllithium was added thereto. A solution was prepared. To this solution, 10 mmol of the above-mentioned silicon-based compound in which both terminals were isobutyric acid ester was slowly added over 30 minutes, and the reaction was further continued for 1 hour with stirring. Then, 40 mmol of trimethylsilyl chloride was added to this solution,
After reacting for 8 hours, low-boiling substances such as a solvent were distilled off under reduced pressure to synthesize a polydimethylsiloxane compound having a ketene silyl acetal at the end. The number average molecular weight of this compound was 11,000.

Further, a reaction vessel equipped with an argon inlet tube, a stirrer, an exhaust pipe, etc. was sufficiently purged with argon, and then 300 ml of sufficiently dehydrated and purified THF and 0.2 ml of trisdimethylaminosulfonium bifluoride (CH ₂ A 0.04 mol solution of CN) and 5 mmol of a polydimethylsiloxane compound having a ketene silyl acetal terminal as an initiator were charged, and the temperature of the reaction system was set to 0 ° C. with stirring. Then
1.0 mol of a mixture (weight ratio: 9/1) of methyl methacrylate (MMA) and glycidyl methacrylate (GMA) was added dropwise over 20 minutes while being careful that the temperature of the reaction system did not exceed 50 ° C. The reaction was carried out for 1 hour to complete the polymerization reaction. Next, 10 ml of methanol containing 0.1 mol of hydrochloric acid was added, and the mixture was stirred for 10 minutes to inactivate the growth terminal of the polymer,
The reaction was stopped.

The polymer is then recovered by precipitation into methanol,
Dry white powder P (MMA / GMA) -PDMS-P (MMA
/ GMA) to obtain a triblock copolymer [PDMS indicates polydimethylsiloxane]. _Mn of this block copolymer is 3
1,000, _Mw was 45,000, and the dimethylsiloxane content was 35% by weight.

This block copolymer was spun in the same manner as in Example 1 to obtain a fiber. A molded product was obtained in the same manner as in Example 1 except that dimethylaminoethyl methacrylate was used instead of glycidyl methacrylate of the monomer mixture for impregnating the fibers of Example 1.

The dimethylsiloxane content of this molded product is 27% by weight, and the oxygen permeability coefficient in the fiber axis direction is 140 × 10 ⁻¹⁰ cm ³ (STP) · cm
/ cm ² · sec · cmHg, and the oxygen permeability coefficient in the direction perpendicular to the fiber axis was 10 × 10 ⁻¹⁰ cm ³ (STP) cm / cm ² · sec · cmHg. The Shore D hardness was 75, and cutting was easy.

Comparative Example 2 A PMMA-PDMS-PMMA triblock copolymer having a dimethylsiloxane content of 34% by weight was synthesized in the same manner as in Example 3 except that GMA was not used ( _Mn = 33,000, _Mw = 43,00).
0). A molded product having a dimethylsiloxane content of 27% by weight was obtained in the same manner as in Example 1 except that this block copolymer was used and no functional monomer was used. The oxygen permeability coefficient was the same as in Example 3, but the Shore hardness was 70, which is lower than that of Example 3.

〔The invention's effect〕

Since the oxygen-permeable molded article of the present invention has a specific higher-order structure, it has higher oxygen permeability in a specific direction than a simple molded article using a polymer having the same composition. Further, by using a functional monomer in the fiber and the monomer composition for impregnation polymerization, a molded article having excellent strength and hardness is obtained. In the present invention, each component exhibits a good synergistic action, and as a result, it has excellent strength, hardness, and transparency that are sufficient for molding and use as a contact lens, etc. It is an oxygen-permeable molded product.

When the molded article of the present invention is used for applications in which the oxygen permeability coefficient is equivalent to that of a general conventional article, the silicon component is reduced by that amount, and a molded article having more excellent tear strength and surface hardness can be obtained. Easy.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI B29K 33:04 105: 08 B29L 11:00 (58) Field surveyed (Int.Cl. ⁶ , DB name) C08F 285 / 00,287 / 00,291 / 00 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A block or graft copolymer comprising polydimethylsiloxane as one component and a copolymer of methyl methacrylate and a functional monomer represented by the following formula (I) as the other component: The fiber bundle is obtained by impregnating the fiber bundle with a monomer composition containing methyl methacrylate, a silicon-containing methacrylate ester and a functional monomer represented by the following formula (I) as main components, and polymerizing the fiber bundle. An oxygen-permeable molded product with excellent strength and hardness. [In the formula (I), R represents -H or -CH _3, X is -
H, CH _{2 n} OH, Or _{- (CH 2 n NR 2 '} ( where R' represents a) shows a CH _{2 m} CH _3, n and m is an integer of 0-5].. 2. A fiber bundle comprising a block or graft copolymer comprising polydimethylsiloxane as one component and a copolymer of methyl methacrylate and (meth) acrylic acid as the other component. The oxidatively permeable molded product according to claim 1, which is obtained by impregnating the fiber bundle with a monomer composition containing methyl methacrylate, silicon-containing methacrylate and glycidyl methacrylate as main components, and polymerizing the fiber bundle.