Silicone hydrogel mixture and wettable silicone hydrogel lenses formed therefrom

Abstract

A silicone hydrogel mixture and a wettable silicone hydrogel lens formed therefrom are provided. [Solution] The silicone hydrogel mixture comprises a polysiloxane polymer, a hydrophilic polymer, and a hydrophilic non-polysiloxane crosslinking agent, wherein the hydrophilic non-polysiloxane crosslinking agent is polyethylene glycol dimethacrylate (PEGDMA) having a structural formula represented by the following formula (A). JPEG2026105801000009.jpg24170 In the formula, R1 and R2 are CH3, or R1 and R2 are H, and n is an integer from 4 to 42.

Description

Technical Field

[0001] The present invention relates to silicone hydrogel lenses, and particularly to a silicone hydrogel mixture and a wettable silicone hydrogel lens having wettability without a surface modification process.

Background Art

[0002] Contact lenses are directly worn on the cornea of the eye during wear, and sufficient oxygen supply is required to maintain the health of the cornea. Since the cornea itself has no blood vessels, it is necessary to obtain oxygen from the dissolved oxygen in the tear layer on the corneal surface. Contact lenses block the contact between tears and air, so the amount of dissolved oxygen in tears may be reduced. In addition, when contact lenses are worn for a long time, tear secretion may decrease and the eyes may become dry, causing eye problems such as dry eye syndrome and keratitis. Therefore, the oxygen permeability and wetness of contact lenses are very important for eye health.

[0003] Conventional hydrogel contact lenses are mainly made of poly-hydroxyethyl methacrylate (poly-HEMA) with high hydrophilicity, and their oxygen permeability (Dk / t) is about 20 to 30. When worn for a long time, it is likely to cause a low oxygen state in the cornea and may cause the above-mentioned ophthalmic diseases. In order to improve the oxygen permeability of contact lenses, contact lenses made of silicone hydrogel have been developed. Silicone hydrogel is obtained by adding silicone to hydrogel. Since silicone molecules can form pores for oxygen to pass through in the material, it has a high oxygen permeability. The oxygen permeability of silicone hydrogel contact lenses reaches 100 Dk / t or more, so it is suitable for long-term wear. Due to its high oxygen permeability, the possibility of occurrence of ophthalmic diseases such as keratitis is reduced.

[0004] However, since silicone hydrogel itself is a hydrophobic material, its surface is not easily wettable. Direct contact lens wear made of hydrophobic material can cause eye discomfort, lead to increased lipid adsorption, and cause protein deposition. To solve this problem, many methods have been developed to modify the surface of silicone hydrogel lenses. For example, hydrophilic components are adsorbed onto the surface of silicone hydrogel lenses using surface coating, chemical adsorption, or plasma technology to improve wettability.

[0005] However, these surface modification methods are too complex and costly. To simplify the process and reduce costs, the industry has developed a method that adds hydrophilic components to the lens material manufacturing process, resulting in a wettable lens material itself that does not require additional surface modification processes.

[0006] However, the surface hydrophilicity of conventional wettable silicone hydrogel lenses still has room for improvement. To provide users with a more comfortable wearing experience and extend wearing time, there is still a need in the field for technical means to improve the surface hydrophilicity of silicone hydrogel lenses. [Overview of the Initiative]

[0007] Therefore, improving the hydrophilicity of the surface of silicone hydrogel lenses in order to provide a more comfortable wearing experience and extend wearing time has become an important issue in the related industry. From these perspectives, the inventors have conducted numerous studies and experiments to solve the above problems and achieve the objective of providing silicone hydrogel lenses with higher surface hydrophilicity.

[0008] The object of the present invention is to provide a mixture for forming a wettable silicone hydrogel lens and a wettable silicone hydrogel lens made from this mixture. The formed lens surface has excellent hydrophilicity, can effectively improve the wettability of the lens surface, and can provide the user with a more comfortable wearing experience and extend the wearing time.

[0009] To achieve the above objective, the present invention provides a silicone hydrogel mixture for forming a wettable silicone hydrogel lens. This mixture comprises a polysiloxane polymer, a hydrophilic polymer, and a hydrophilic non-polysiloxane crosslinking agent. The hydrophilic non-polysiloxane crosslinking agent is polyethylene glycol dimethacrylate (PEGDMA) having the structural formula represented by the following formula (A). In formula JPEG2026105801000001.jpg27170, R1 and R2 are CH3, or R1 and R2 are H, and n is preferably an integer from 4 to 42.

[0010] Furthermore, the present invention provides a wettable silicone hydrogel lens formed from the above-mentioned silicone hydrogel mixture.

[0011] In practice, the polyethylene glycol dimethacrylate (PEGDMA) content is 2 to 15% by weight of the silicone hydrogel mixture.

[0012] In practice, the wettable silicone hydrogel lens preferably has a dynamic contact angle of 50° or less.

[0013] Compared to conventional technologies, wettable silicone hydrogel lenses made from the silicone hydrogel mixture provided in the present invention have a smaller droplet contact angle and can reliably improve the surface hydrophilicity of the lens. [Modes for carrying out the invention]

[0014] The present invention relates to a silicone hydrogel mixture for forming a wettable silicone hydrogel lens. The silicone hydrogel mixture of the present invention comprises a polysiloxane polymer, a hydrophilic polymer, and a hydrophilic non-polysiloxane crosslinking agent. The hydrophilic non-polysiloxane crosslinking agent is polyethylene glycol dimethacrylate (PEGDMA) having a structural formula represented by the following formula (A). In formula JPEG2026105801000002.jpg27170, R1 and R2 are CH3, or R1 and R2 are H, and n is preferably an integer from 4 to 42.

[0015] Furthermore, the present invention provides a wettable silicone hydrogel lens formed from the above-mentioned silicone hydrogel mixture.

[0016] In some embodiments, the polyethylene glycol dimethacrylate (PEGDMA) content is 2 to 15% by weight of the silicone hydrogel mixture.

[0017] In some examples, the content of the polysiloxane polymer is preferably 5 to 50% by weight of the silicone hydrogel mixture, more preferably 15 to 50% by weight, and even more preferably 25 to 50% by weight.

[0018] In some embodiments, the polysiloxane polymer comprises (3-Methacryloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (SiGMA). It has a structural formula represented by the following formula (B). JPEG2026105801000003.jpg34170 The content of (3-methacryloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (SiGMA) is preferably 5 to 40% by weight of the silicone hydrogel mixture.

[0019] In some embodiments, the hydrophilic polymer may be polyvinylpyrrolidone (PVP). The PVP content is preferably 0.1 to 10% by weight of the silicone hydrogel mixture.

[0020] The average molecular weight of polyvinylpyrrolidone (PVP) was measured by gel permeation chromatography (GPC). The measured average molecular weight is usually expressed as a K value. The K value of the PVP used in this invention is 90.

[0021] In the silicone hydrogel mixture described above, the molecular chains of polyvinylpyrrolidone (PVP) and the three-dimensional network formed of polysiloxane polymers can form an interpenetrating polymer network (IPN) structure and / or a semi-interpenetrating polymer network (semi-IPN) structure. An interpenetrating polymer network (IPN) refers to a structure formed by the interpenetration of two or more reticular structures made of polymers at least partially on a polymer scale. The polymer reticular structure is formed by covalently bonded polymers. There are no covalent bonds between the polymers within the interpenetrating network. Nevertheless, the IPN structure is difficult to separate unless the chemical bonds in the reticular structure are broken. There is also a so-called semi-interpenetrating polymer network (semi-IPN) structure. Its characteristics include a structure formed by the interpenetration of one or more networks and one or more linear or branched polymers at a polymer scale, and there are no covalent bonds between the interpenetrating polymers.

[0022] In some embodiments, the silicone hydrogel mixture may contain other hydrophilic polymers. This other hydrophilic polymer can form polymer entanglements in the IPN structure or semi-IPN structure with polyvinylpyrrolidone (PVP), whereby PVP becomes more stable and less likely to fall off in the IPN structure or semi-IPN structure. Polymer entanglement refers to a network or spherical structure formed by cross-linking points within or between polymer chains. Polymer entanglement prevents the polymer chains from moving normally, thereby affecting the properties of the polymer.

[0023] In some embodiments, the other hydrophilic polymer can be formed by polymerizing N-vinyl-2-pyrrolidinone (NVP) monomer. Its content is preferably 5 to 40% by weight of the silicone hydrogel mixture.

[0024] The wettability (hydrophilicity) of the material surface is usually determined by the angle of the liquid / gas interface of the droplet on the material surface. This angle is generally called the dynamic contact angle (DCA). The smaller the dynamic contact angle, the higher the hydrophilicity of the material surface. The dynamic contact angle of a hydrophobic material surface is greater than 90°.

[0025] The wettable silicone hydrogel lens formed of the above silicone hydrogel mixture preferably has a dynamic contact angle of 70° or less, more preferably 60° or less, and even more preferably 50° or less.

[0026] Hereinafter, the composition and effects of the mixture of the present invention will be described with reference to some examples. However, these examples do not limit the present invention. The abbreviations of the compounds used in the examples are shown in Table 1.

[0027] JPEG2026105801000004.jpg89170

[0028] Tables 2 and 3 show the reaction components and results of the silicone hydrogel mixtures of Examples 1 to 11. Here, Examples 1 to 7 are comparative examples, and Examples 8 to 11 are examples of the present invention. The unit of the content of each reaction component shown in the table is weight percentage.

[0029] JPEG2026105801000005.jpg75170

[0030] JPEG2026105801000006.jpg98170

[0031] The examples of the silicone hydrogel lenses shown in Tables 2 and 3 were prepared as follows. The reaction components and the diluent (TAA) were mixed for at least 12 hours while stirring or rotating at a temperature of about 23°C until all the components were dissolved. Here, the content of the reaction components is expressed as the weight percentage of the mixture of all the reaction components except the diluent (TAA) and the dye (RB246), and the contents of the diluent (TAA) and the dye (RB246) are expressed as the weight percentage of the final reaction mixture. After the mixing was completed, the reaction mixture was put into a thermoplastic contact lens mold, and then a curing process was carried out. The curing process includes the following steps. First, it was flushed in nitrogen for 1 hour, then heated to 90°C at a rate of 45°C / min, and then cured at a temperature of 90°C for 24 hours. The oxygen concentration in the curing furnace is preferably less than 500 ppm, and more preferably less than 100 ppm. After the curing process was completed, the mold was opened, the cured lens was taken out, put into a borate buffer solution, and immersed in the borate buffer solution at 80°C for 3 hours to remove the residual monomers and diluent. The properties of the obtained lenses are shown in Tables 2 and 3.

[0032] Tables 2 and 3 show three properties tested for the completed lenses: dynamic contact angle (DCA), oxygen permeability (Dk), and visible light transmittance (VLT).

[0033] Dynamic contact angle (DCA) was measured using a droplet shape analyzer DSA25 (KRUSS Optronic) and a contact lens adapter. Lenses were stored and tested in borate buffer. Oxygen permeability was measured using a Rhder O2 Permeometer model 201T (Rhder O2 Permeometer model 201T) according to the method described in the international standard ISO 9913-1. Visible light transmittance (VLT) was measured using a spectrophotometer.

[0034] Examples 1-6 (comparative examples) differ in the amounts of DMA, HEMA, and PVP in the reaction components. Table 2 shows the test results for the lenses of Examples 1-6. As can be seen from the results, increasing the HEMA content can improve the visible light transmittance of the lens.

[0035] Table 3 shows Examples 8-11. For convenience of comparison, Examples 6-7 (Comparative Examples) are also shown in Table 3. The mixture formulations of Examples 6-11 differ in that they use non-polysiloxane crosslinking agents with different degrees of polymerization n. The crosslinking agent used in Example 6 (Comparative Example) was EGDMA (n=1), the crosslinking agent used in Example 7 (Comparative Example) was TEGDMA (n=3), and the crosslinking agents used in Examples 8-11 were PEGDMA330 (n=4), PEGDMA550 (n=9), PEGDMA750 (n=14), and PEGDMA2000 (n=42), respectively. As can be seen from the test results shown in Table 3, the silicone hydrogel lenses provided in Examples 8-11 all exhibit good properties (including good contact angle, appropriate oxygen permeability, and transparency) in each property test. In particular, regarding the dynamic contact angle test results, the dynamic contact angles of Examples 8 to 11 were all less than 50° compared to Examples 1 to 7, which is significantly smaller than the dynamic contact angles measured in Examples 1 to 7, indicating that the silicone hydrogel mixture of the present invention can improve the hydrophilicity of lenses.

[0036] Therefore, the silicone hydrogel mixture provided in the present invention and the wettable silicone hydrogel lenses made from this mixture can achieve the objectives of the present invention, possess higher hydrophilicity, and effectively improve the wettability of the lens surface, thereby providing the user with a more comfortable wearing experience and extending the wearing time.

[0037] Furthermore, the wettable silicone hydrogel lenses provided in this invention can effectively reduce the use of organic solvents in the process and significantly simplify the process of recovering waste organic solvents, thus making the process environmentally friendly and cost-effective.

[0038] The above description represents preferred embodiments of the present invention, and the formulation ratios and process conditions are not readily apparent to those skilled in the art. However, the embodiments of the present invention can be modified in various other ways, and the scope of the present invention is not limited to the above embodiments. Therefore, those skilled in the art can modify and improve the above embodiments as appropriate based on their knowledge, without departing from the spirit of the present invention.

Claims

1. A silicone hydrogel mixture for forming a wettable silicone hydrogel lens, The aforementioned silicone hydrogel mixture is Polysiloxane polymers, Hydrophilic polymers and Hydrophilic non-polysiloxane crosslinking agent, The hydrophilic non-polysiloxane crosslinking agent is polyethylene glycol dimethacrylate (PEGDMA) having a structural formula represented by the following formula (A), In the formula, R １ and R ２ CH ３ is, or R １ and R ２ A silicone hydrogel mixture in which H is and n is an integer from 4 to 42.

2. The silicone hydrogel mixture according to claim 1, wherein the content of the polysiloxane polymer is 5 to 50% by weight of the silicone hydrogel mixture.

3. The polysiloxane polymer includes (3-methacryloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (SiGMA) having a structural formula represented by the following formula (B), The silicone hydrogel mixture according to claim 1, wherein the content of (3-methacryloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (SiGMA) is 5 to 40% by weight of the silicone hydrogel mixture.

4. The silicone hydrogel mixture according to claim 1, wherein the hydrophilic polymer comprises a first hydrophilic polymer, the first hydrophilic polymer being polyvinylpyrrolidone (PVP), and the PVP content being 0.1 to 10% by weight of the silicone hydrogel mixture.

5. The silicone hydrogel mixture according to claim 4, wherein the K value of the polyvinylpyrrolidone (PVP) is 90.

6. The silicone hydrogel mixture according to claim 4, wherein the polysiloxane polymer forms a three-dimensional network, and the first hydrophilic polymer and the three-dimensional network formed by the polysiloxane polymer form an interpenetrating polymer network structure and / or a semi-interpenetrating polymer network structure.

7. The silicone hydrogel mixture according to claim 6, wherein the hydrophilic polymer further comprises a second hydrophilic polymer, and the second hydrophilic polymer and the first hydrophilic polymer form polymer entanglements in the interpenetrating polymer network structure and / or semi-interpenetrating polymer network structure.

8. The silicone hydrogel mixture according to claim 4, wherein the hydrophilic polymer further comprises a second hydrophilic polymer, the second hydrophilic polymer being obtained by polymerizing an N-vinyl-2-pyrrolidone (NVP) monomer, and the content of the second hydrophilic polymer is 5 to 40% by weight of the silicone hydrogel mixture.

9. The silicone hydrogel mixture according to claim 1, wherein the content of polyethylene glycol dimethacrylate (PEGDMA) is 2 to 15% by weight of the silicone hydrogel mixture.

10. A wettable silicone hydrogel lens formed from a silicone hydrogel mixture according to any one of claims 1 to 9.

11. The wettable silicone hydrogel lens according to claim 10, wherein the wettable silicone hydrogel lens has a dynamic contact angle of 50° or less.

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