JPS61166516A - Contact lens having high moisture content - Google Patents

Abstract

PURPOSE:To obtain the title lens having a high moisture content and a large tensile strength by incorporating a copolymer composed of dimethyl acrylamide, a hydrophobic monomethacrylate and a specific cross-linking agent to the title lens. CONSTITUTION:The contact lens having >=60% moisture content comprises copolymer of 50-85wt% dimethyl acrylamide, 15-50wt% at least one of the hydrophobic monomethacrylate and 0.3-3.0wt% cross-linking agnt. The cross linking agent is preferably dimethacrylate having a some extent of a molecular length. If the ordinary cross-linking agent such as ethylene glycol dimethacrylate and divinylbenzene having a short molecular length is used, said cross-linking agent does not contribute to the improvement of the tensile strength of the polymer contg. the high moisture. While, the cross-linking agent having a very long molecular chain such as polyethylene glycol dimethacrylate, for example, ethylene oxide 14mol adduct, does not remarkably improve the strength of the polymer contg. a high moisture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel high water content contact lens, and more particularly, to a high water content contact lens that has a high water content, high mechanical strength, and is colorless and transparent. .

Conventionally, soft contact lens materials have mainly been O.
Homopolymers or copolymers of acrylic derivatives with H groups have been used. These materials have the property of absorbing water and swelling, have good transparency, and have excellent machinability, making soft contact lenses that are comfortable to wear. It is suitable for

Furthermore, in recent years, high water-containing soft contact lenses have appeared that are intended to be worn continuously for long periods of time by further increasing the water content of lens materials. This high water content soft contact lens is made of a material whose main component is N-vinylpyrrolidone and can absorb a large amount of water.
It maintains the metabolic function of the cornea and contributes to the physiological safety of the eye.

However, when the water content of this material increases, its strength rapidly decreases, which causes problems in durability, such as damage to the lens or scratches on the lens surface. In addition, because the water retention properties of the material itself are insufficient, the lenses tend to dry out easily.
It has the disadvantage that the shape is unstable.

As a result of intensive research aimed at improving the drawbacks of such high water content soft contact lenses, the present inventors found that by copolymerizing dimethyl acrylamide, hydrophobic monomethacrylate, and a specific crosslinking agent in a certain ratio, high water content and high strength are achieved. They discovered that it is possible to obtain a lens material that can simultaneously express the following, and have completed the present invention.

An object of the present invention is to provide a contact lens that has both a high water content of 60% or more and high tensile strength.

Another object of the present invention is to provide a high water content contact lens that has high oxygen permeability and can be worn continuously for a long period of time.

The present invention comprises 50 to 85% by weight of dimethylacrylamide,
At least one hydrophobic monomethacrylate 15-50
A high water content contact lens with a water content of 60% or more consisting of a copolymer containing 0.3 to 3.0% by weight of at least one crosslinking agent selected from Group A below. is a constituent element of the invention.

<Group A) XX CH2=CCoo (C1h (J(20), QC-
C=C)-12 (X is H or CH3, a is an integer from 2 to 4)
×CH2=C-Coo (CH2CH2CH20)
bQCC=CH2 (X is I-1 or CH3, b is 2
Integer up to 4)X CH3X l 1 1 CH2=C-Coo (CH2CH20) cQC-C
=CH2 (X is H or CH3, C is an integer from 2 to 4) × × CH2=C-Coo (CH2), QC-C=CH2
(X is H or CH3, !2 is an integer from 2 to 4)
CH3Xl
1 1EH
2=CCOO(CH2CH20) lφCφ(OCH2
CH2). 0OCC=CH2OH3 (X is H or CH3, m and n are integers from 0 to 2, φ
(benzene ring) Hydrophobic monomethacrylates in the above requirements include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, 1so-butyl methacrylate, n-butyl methacrylate, 5ec-
Butyl methacrylate, n-pentyl methacrylate,
Furkyl methacrylates such as 2-ethylhexyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate: phenyl methacrylate, p-methylphenyl methacrylate, p-methoxyphenyl methacrylate, p-ethoxyphenyl methacrylate,
Phenyl methacrylates such as biphenyl methacrylate and p-henzylnoenyl methacrylate: and benzyl methacrylate, methylbenzyl methacrylate, p-
- Benzyl methacrylates such as methylbenzyl methacrylate, 0-methoxybenzyl methacrylate, p-methoxybenzyl methacrylate, p-ethoxybenzyl methacrylate, p-n-butylbenzyl methacrylate, phenoxybenzyl methacrylate, and p-phenylbenzyl methacrylate-1. can be mentioned. The use of these hydrophobic monomethacrylates is effective for controlling water content and imparting tensile strength, among others:
Cyclohexyl methacrylate exhibits a particularly remarkable effect on imparting tensile strength.

As the crosslinking agent used in the present invention, dimethacrylates having a certain molecular length as shown in Group A above are preferred. Even if commonly used short-chain crosslinking agents such as ethylene glycol dimethacrylate and divinylbenzene are used, they do not significantly contribute to improving the tensile strength of highly hydrated borine. Also, extremely long chain crosslinking agents such as polyethylene glycol dimethacrylate (eg, 14 moles of ethylene oxide added) cannot significantly improve the strength of highly water-containing polymers.

The amount of crosslinking agent added varies depending on the type of crosslinking agent used, but is preferably in the range of 0.1 to 380% by weight. If the amount used is outside this range, the tensile strength will be extremely low and it cannot be used practically. Crosslinking agent of the present invention ・! By using an appropriate amount of □, the tensile strength can be significantly improved compared to when it is not used.

The high water content contact lens of the present invention comprises 50 to 85% by weight of dimethyl acrisifamide, 15 to 50% by weight of at least one hydrophobic monomethacrylate, 011 to 3.0% by weight of a crosslinking agent selected from Group A, and Polymerization initiator 0.01
A liquid mixed with ~0.1% heavy scratching is injected into a specified mold and sealed, heated in a constant temperature bath for a certain period of time, and the obtained bar material is cut and polished to a certain thickness. A lens can be obtained by saturated swelling in physiological saline.

The polymerization initiators used here include azobis-based initiators such as azobisisobutyronitrile and azobisvaleronitrile, and peroxide-based initiators such as benzoyl peroxide, lauroyl peroxide, and diisopropyl baroxydidicarbonate. can be mentioned.

The contact lens of the present invention obtained as described above has the following excellent properties.

(1) Since the main component is dimethylacrylamide, which is a highly water-containing material, it has a water content high enough to pass through the corneal physiologically necessary amount of oxygen.

(2) Despite its high water content, it has a tensile strength that is unimaginable for conventional contact lenses.

(3) The contact lens of the present invention is colorless and transparent, without the pale yellow coloring that conventionally commercially available polyN-vinylpyrrolidone soft contact lenses have, and has a high visible light transmittance.

(4) There is little variation in lens shape in the expanded state.

Conventionally used poly-N-vinylpyrrolidone type hydrous contact lenses do not have a strong water-retention ability due to the material itself, so when used in a dry atmosphere, the water in the lenses evaporates and the water content changes. As a result, there is a defect that the lens shape deviates from the set shape.

The high water content contact lenses of the present invention are mainly composed of dimethylacrylamide, which has strong water retention ability, and are copolymerized with a considerable amount of hydrophobic monomethacrylate, so water evaporation is suppressed and there is almost no change in shape. It has the feature that it cannot be damaged.

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 A liquid mixture consisting of 60 parts of dimethylacrylamide, 40 parts of methyl methacrylate, 0.28511 parts of triethylene glycol dimethacrylate, and 0.05 parts of azobisisobutyronitrile was poured into a mold. was sealed and then heated. Heating is in a constant temperature bath for 50℃
The temperature was increased from .degree. C. to 115.degree. C. over 24 hours. After the polymerization was completed, the copolymer was cooled to room temperature for 7J1 hours and taken out from the mold. The copolymer was a colorless and transparent hard material.

This was then cut and polished into the shape of a contact lens using normal processing techniques to produce a contact lens.

Next, it was immersed in 0.9% physiological saline to make it sufficiently swollen. The swollen soft contact lens was as clear and colorless as the dry state.The water content of this lens was 71.
．． 5%, oxygen permeability coefficient is 36X10 art (S
TP) cm/c1sec -11++aHg (30
°C), the tensile strength when hydrated was 125 (1/arm2), and the visible light transmittance was 91.5% (550 ni)-Q.

Examples 2 to 13 Contact lenses with saturated swelling were produced in the same manner as in Example 1. Table 1 shows the physical properties of the seven lenses used and the contact lenses obtained. All examples showed higher oxygen permeability than Comparative Example 1, and -C, which is a high water content contact lens, had a high tensile strength never seen before. (Left below) Table 1 (Monomer abbreviation) NVP N-vinylvinylidene DMAA Dimethylacryl 7mide MMA
Methyl methacrylate BuMA n-butyl methacrylate EHMA
2-ethylhexyl methacrylate CHMA cyclohexyl methacrylate BzMA
Benzyl methacrylate A Triethylene glycol dimethacrylate B Tripropylene glycol dimethacrylate C Hexamethylene glycol dimethacrylate D 2.2-Bis(4-methacryloxyjethoxyphenyl) 10pan E Ethylene glycol dimethacrylate (Note 1) Water content ( Weight%) = (WI W2) x 1G
For G/WIW1, the vehicle weight W2 at saturated water content is the weight when the lens is dehydrated and dried (Note 2). It was measured.

The unit is 10 ail (STP) cm/cm2-
sec -aa+lIg.

(Note 3) Tensile strength is 2 at a constant loading rate of Boo/min.
Determined by measuring the breaking strength in physiological saline at 0''C.Unit: g7112゜Applicant: Hoya Co., Ltd.

Claims (1)

[Claims] 1. 50-85% by weight of dimethylacrylamide, 15-50% by weight of at least one hydrophobic monomethacrylate.
and at least one crosslinking agent selected from Group A 0.1-
Water content: 60, consisting of a copolymer containing 3.0% by weight
% or higher water content contact lenses. (Group A) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (X is H or CH_3, a is an integer from 2 to 4) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (X is H or CH_3, b is 2 (Integer up to 4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (X is H or CH_3, c is an integer from 2 to 4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (X is H or CH_3, l is an integer from 2 to 4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (X is H or CH_3, m and n are integers from 0 to 2,
φ is a benzene ring) 2 The hydrophobic monomethacrylate is alkyl methacrylates, phenyl methacrylates,
The high water content contact lens according to claim 1, which is one or more monomers selected from the group consisting of benzyl methacrylates.