JPH0551417A - Fluorine-containing copolymer - Google Patents

Abstract

PURPOSE:The subject copolymer containing two kinds of specific structural units in a specified solar ratio, having excellent transparency, oxygen permeability and stain resistance and useful as a highly oxygen-permeable material. CONSTITUTION:The objective copolymer constituted from one kind or more of structural units of formula II derived from an itaconic acid diester monomer of formula I (R<1>, R<2> are hydrocarbon group) and from one kind or more of structural units of formula IV derived from a fluorine-containing itaconic acid diester monomer of formula III (R<3>, R<4> are hydrocarbon which may be substituted with a fluorine atom, at least one of R<3> and R<4> being a hydrocarbon substituted with three or more fluorine atoms; X is H, trifluoromethyl) in a molar ratio of 10/90 to 90/10 (preferably 30/70 to 70/30).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel fluorine-containing copolymer. The fluorine-containing copolymer provided by the present invention has excellent transparency, oxygen permeability, and stain resistance,
It is useful as a high oxygen permeable material.

[0002]

2. Description of the Related Art Conventionally, contact lenses made of a composition containing polymethacrylate as a main component have been put into practical use. Although this polymethacrylate has great advantages such as excellent transparency, optical performance, and mechanical properties,
There is a problem with oxygen permeability. Wearing such a contact lens made of a material having poor oxygen permeability is likely to impair oxygen supply to the eyeball, and long-term wearing often causes hyperemia, edema and other corneal disorders.

In order to improve the oxygen permeability of the methacrylic acid ester-based polymer, it has been attempted to introduce a large amount of fluorine atom or silicon atom into the monomer molecule. For example, fluorine atom or itaconic acid diester molecule may be incorporated into the molecule. A contact lens comprising a fluoroalkyl itaconate-based monomer having an oligosiloxane bond introduced therein or a copolymer of an oligosiloxanyl itaconate-based monomer and a methacrylic acid ester-based monomer has been proposed (JP 60-320
No. 22, JP-A-62-92914 and JP-A-63-210115).

However, the copolymer containing the oligosiloxanyl itaconate-based monomer has improved oxygen permeability as compared with conventional polymethacrylates such as polymethylmethacrylate (PMMA), but it is not sufficient. Furthermore, improvement of oxygen permeability is required. Further, the copolymer containing the oligosiloxanyl itaconate-based monomer is not satisfactory in stain resistance.

In order to improve the oxygen permeability and the stain resistance of the above-mentioned copolymer, methacrylic acid substituted with a fluorine atom, which is a polymer containing no silicon atom, which is considered to be the cause of contamination, is used. A contact lens made of a copolymer composed of an ester and an itaconic acid ester substituted with a fluorine atom has been proposed (JP-A-63-210).
115). However, although this copolymer has improved oxygen permeability and stain resistance, it is not yet sufficient in terms of oxygen permeability, and since both raw material compounds use fluorine atom-substituted monomers. The cost is not satisfactory either.

[0006]

The present inventors have recognized that conventional oxygen permeable materials, especially materials for contact lenses, are in the above-mentioned situation, and are excellent in oxygen permeability and expensive fluorine-containing monomer. As a result of earnest studies on oxygen-permeable materials with a low content, a molded product obtained by combining an itaconic acid ester derivative substituted with a fluorine atom and an itaconic acid ester derivative not substituted with a fluorine atom in an appropriate ratio was contacted. They have found that they have mechanical properties and thermal properties that can be practically used as a lens, and they also have excellent oxygen permeability.

The object of the present invention is to provide a novel fluorine-containing itaconic acid diester-based copolymer which has mechanical properties and thermal properties at a level practical for use as a highly oxygen permeable material, especially as a contact lens, and which has excellent oxygen permeability. To provide a coalesce.

[0008]

According to the present invention, the above object is achieved by the following general formula (I):

[0009]

[Chemical 3]

One or more structural units (A) represented by the formula (wherein R ¹ and R ² each represent a hydrocarbon group), and the following general formula (II)

[0011]

[Chemical 4]

(In the formula, R ³ and R ⁴ each represent a hydrocarbon group which may be substituted with a fluorine atom, and R ³
And at least one of R ⁴ represents a hydrocarbon group substituted with at least 3 fluorine atoms, and X represents a hydrogen atom or a trifluoromethyl group), and one or more kinds of structural units (B) Consisting of a structural unit (A)
/ Molar ratio of structural unit (B) is 10/90 to 90/1
This is accomplished by providing a fluorine containing copolymer in the range of 0.

The structural unit (A) corresponds to the corresponding general formula (I ')

[0014]

[Chemical 5]

It is derived from the itaconic acid diester monomer represented by the formula (wherein R ¹ and R ² are as defined above).

The hydrocarbon groups represented by R ¹ and R ² in the above general formulas (I) and (I ′) may have a branched chain, and those having 1 to 20 carbon atoms are preferable, and Those having 1 to 10 atoms are more preferable. Examples of such a hydrocarbon group include the following groups.

[0017]

[Chemical 6]

Of these hydrocarbon groups, an isopropyl group, a tert-butyl group, a neopentyl group and a cyclohexyl group (which are represented by C ₆ H ₁₁ in the present specification) are particularly preferable.

Among the itaconic acid diester monomers represented by the general formula (I '), preferable monomers are shown below.

[0020]

[Chemical 7]

Among these itaconic acid diester monomers, particularly preferred monomers are shown below.

[0022]

[Chemical 8]

Further, the structural unit (B) corresponds to the corresponding general formula (II ')

[0024]

[Chemical 9]

It is derived from a fluorine-containing itaconic acid diester monomer represented by the formula (wherein R ³ , R ⁴ and X are as defined above).

In the above general formulas (II) and (II '), a hydrocarbon group which may be substituted by a fluorine atom represented by R ³ and R ⁴ and a hydrocarbon group which is substituted by at least 3 fluorine atoms. Is preferably one having 1 to 20 carbon atoms, and 1 to 10 carbon atoms.
It is more preferable to have Examples of the hydrocarbon group not substituted by a fluorine atom include the hydrocarbon groups represented by R ¹ and R ² in the above general formulas (I) and (I ′), and the hydrocarbon group substituted by a fluorine atom. As the group, a hydrocarbon group substituted with at least 3 fluorine atoms is preferable.

Examples of such a hydrocarbon group substituted with at least 3 fluorine atoms include the following groups. _{-CF 3, -CF 2 CF 3,} -CF 2 CF 2 H, -CH 2 CF
_{2 CF 3, - (CF 2} ) 3 CF 2 H, -CH 2 (CF 2) 3 CF
_{3, -CH 2 (CF 2)} 5 CF 3, -CH 2 (CF 2) 7 C
_{F 3, -CH 2 (CF 2} ) 9 CF 3,

[0028] Of these fluorine-substituted hydrocarbon group, in particular _{- (CF 2) 3 CF 2} H, -CH 2 (CF 2) 3 CF 3, -
_{CH 2 (CF 2) 5 CF} 3, -CH 2 (CF 2) 7 CF 3 and _{-CH 2 (CF 2) 9 CF} 3 are preferred.

Among the fluorine-containing itaconic acid diester monomers represented by the general formula (II '), preferable monomers are shown below.

[0030]

[Chemical 10]

Of these fluorine-containing itaconic acid diester-based monomers, particularly preferable monomers are shown below.

[0032]

[Chemical 11]

The fluorine-containing copolymer of the present invention comprises the structural unit (A) and the structural unit (B) in a molar ratio of the former / the latter of 10:
It is included in the range of / 90 to 90/10. Structural unit (A)
The molar ratio of the structural unit (B) and the structural unit (B) is preferably in the range of 20/80 to 80/20, and more preferably in the range of 30/70 to 70/30.

When the proportion of the structural unit (A) is less than 10 mol%, a molded product having mechanical properties practical for a contact lens cannot be obtained, and when it exceeds 90 mol%, the oxygen permeation of the copolymer is increased. It is not preferable because it is inferior in properties.

When the proportion of the structural unit (B) is less than 10 mol%, the oxygen permeability of the copolymer is lowered, and it is 90 mol%.
If it exceeds, it is not preferable because a molded product having mechanical properties practically usable as a contact lens cannot be obtained.

The above-mentioned fluorine-containing copolymer comprises one or more structural units (A) and one structural unit (B).
It may be composed of one or more kinds, and in addition to these structural units, other copolymerization components such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, etc. within a range that does not impair the performance as an oxygen permeation body. A structural unit derived from a polyfunctional monomer such as triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, allyl methacrylate, or trimethylolpropane trimethacrylate may be contained at any ratio.

The fluorine-containing copolymer of the present invention requires an itaconic acid diester monomer represented by the general formula (I ') and a fluorine-containing itaconic acid diester monomer represented by the general formula (II'). According to the above, it can be produced by polymerizing a monomer mixture containing other copolymerization components in the presence of a polymerization initiator. Among the polymerization initiators, as a radical initiator for thermal polymerization, azobisisobutyronitrile, azobiscyclohexanecarbonitrile,
Dimethylazobisisobutyrate, azobisdimethylvaleronitrile, benzoyl peroxide, di-t-butyl peroxide, etc. can be used.

The temperature during the thermal polymerization is preferably in the range of 40 to 100 ° C, more preferably 50 to 80 ° C. The time required for the polymerization is preferably 1 to 100 hours, more preferably 2 to 40 hours.

The molecular weight of the fluorine-containing copolymer of the present invention is
When a high oxygen permeable material is intended, the number average molecular weight (in terms of polystyrene) determined by gel permeation chromatography is usually 10,000 to 30,000.
It is preferably in the range of 0, 100,000 to 250
The range of 000 is more preferable.

Depending on the polymerization conditions, a copolymer which is insoluble in a solvent for measuring the molecular weight and whose molecular weight cannot be measured may be obtained. Such a copolymer is also included in the present invention.

The glass transition temperature (T) of the fluorine-containing copolymer of the present invention measured by a differential scanning calorimeter (DSC).
g) is preferably in the range of 40 to 200 ° C.

The molded product obtained from the fluorine-containing copolymer of the present invention has excellent oxygen permeability, and has an oxygen permeability coefficient (DK value: unit: 10 ⁻¹⁰ cc (STP) cm / cm ^{2 at} 35 ° C.
・ Sec · cmHg) is usually 30 or more. The oxygen permeability coefficient of the one having more excellent oxygen permeability is 50 or more, and the oxygen permeability coefficient of the one having particularly excellent oxygen permeability is 70 or more. Here, the oxygen permeation coefficient was measured on a homogeneous thin film sample (thickness: 200 to 400 μm) by using a film oxygen permeability meter of Seikaken type. This technique is to measure the amount of oxygen that has permeated a film fixed in front of an oxygen electrode in pure water saturated with oxygen at 35 ° C. as the amount of change in reduction current.

The molded product obtained from the fluorine-containing copolymer provided by the present invention has mechanical properties and thermal properties that can be practically used as a contact lens, has excellent oxygen permeability despite being low in fluorine content, and is transparent. Excellent in wearability, wearability and stain resistance.

[0044]

EXAMPLES The present invention will be specifically described below with reference to examples.

Reference Example 1 Itaconic acid CH ₂ = C (COOH) CH ₂ COOH130
g (1.0 mol), 1H, 1H, 2H, 2H- perfluorooctanol _{[CF 3 (CF 2) 5} CH 2 CH 2 OH]
250 g (0.69 mol), 5.0 g of p-toluenesulfonic acid monohydrate, 0.1 g of p-methoxyphenol were added to 5 g.
The mixture was mixed with 00 ml of toluene and reacted at 110 ° C. for 8 hours. During this time, water generated by using the Dean Stark trap was removed to the outside of the system to promote the reaction. After the reaction, toluene was distilled off from the reaction solution, the residue was dissolved in methylene chloride, sodium sulfate was added to the obtained solution and the mixture was filtered, and the filtrate was evaporated. The viscous liquid obtained was purified by distillation to obtain a colorless and transparent viscous liquid. It was confirmed by ¹ H-NMR analysis that the liquid had the following structural formula.

[0046]

[Chemical formula 12]

Reference Examples 2 and 3 Instead of 1H, 1H, 2H, 2H-perfluorooctanol in Reference Example 1, 1H, 1H, 2H, 2H-perfluorohexanol [CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ CH ₂
OH] or to give 1H, 1H, 2H, 2H- perfluoro octadecanol [CF ₃ and _{(CF 2) 7 CH 2 CH} 2 OH] respectively by the use of the compounds. It was confirmed by ¹ H-NMR analysis that these compounds were represented by the following structural formula.

[0048]

[Chemical 13]

[0049]

[Chemical 14]

Examples 1 to 3 The compounds obtained in Reference Examples 1 to 3 and dineopentyl itaconate were mixed at a predetermined ratio, 0.113 mol% of dimethylazobisisobutyrate was added, and the mixture was sufficiently stirred. The mixture was mixed, freeze-vacuum degassed in a polymerization tube, and sealed.
The polymerization tube was placed in a constant temperature bath and heated at 60 ° C. for 24 hours to carry out polymerization. After completion of the polymerization, the polymer was taken out by reprecipitation purification. After vacuum drying, the polymer was sandwiched between flat metal plates, heated and melted, pressurized and allowed to cool to prepare a transparent film (thickness: 200 to 400 μm), and the oxygen permeability coefficient was measured. Table 1 shows the structure, number average molecular weight (in terms of polystyrene), and oxygen permeability coefficient of the obtained polymer. In addition,
The composition ratio of the copolymer is ¹ H-NMR of a heavy chloroform solution.
It was determined by measuring the spectrum. The oxygen permeability coefficient was measured at 35 ° C. by using a film oxygen permeability meter of Seikaken type.

[0051]

[Table 1]

Comparative Example 1 50 mol% of the compound obtained in Reference Example 1 in Example 1
Polymerization was carried out in the same manner except that 50 mol% of neopentylmethacrylate was used in place of dineopentylitaconate, and the resulting polymer (film: thickness:
It was DK24 when the oxygen permeation coefficient was measured in the same manner.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 1 except that 50 mol% of 1H, 1H, 2H, 2H-perfluorooctylmethacrylate was used in place of the compound obtained in Reference Example 1 to obtain a polymer. Film from polymer (thickness: 280μ
m) was prepared and the oxygen permeation coefficient was measured in the same manner, resulting in DK29.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 using only dineopentyl itaconate, and a film (thickness: 400 μm) was prepared from the obtained polymer. This film was used as a contact lens. It did not have a practical mechanical strength.

Comparative Example 4 Di (1H, 1H, 2H, 2H-perfluorooctyl)
Polymerization was carried out in the same manner as in Example 1 using only itaconate, and a film (thickness: 300 μm) was obtained from the obtained polymer.
m) was prepared, but this film did not have mechanical strength and thermal properties that could be practically used as a contact lens.

[0056]

[Table 2]

[0057]

The novel fluorine-containing copolymer provided by the present invention has excellent oxygen permeability.

Claims (1)

[Claims] 1. The following general formula (I): (In the formula, R ¹ and R ² each represent a hydrocarbon group), one or more structural units (A) represented by the following general formula (II) (In the formula, R ³ and R ⁴ each represent a hydrocarbon group optionally substituted with a fluorine atom, and at least one of R ³ and R ⁴ represents a hydrocarbon group substituted with at least 3 fluorine atoms. , X represents a hydrogen atom or a trifluoromethyl group) and is composed of one or more structural units (B) represented by the structural unit (A) / structural unit (B).
A fluorine-containing copolymer having a molar ratio of 10/90 to 90/10.