Silicone hydrogel mixture and wettable silicone hydrogel lens formed therefrom

Abstract

The present invention provides a silicone hydrogel mixture and a wettable silicone hydrogel lens formed therefrom. The silicone hydrogel mixture comprises a polysiloxane macromolecule, a hydrophilic polymer, and a hydrophilic non-polysiloxane cross-linking agent, wherein the hydrophilic non-polysiloxane cross-linking agent is polyethylene glycol dimethacrylate (PEGDMA) having the following structural formula represented by formula (A): wherein R1 and R2 are CH3, or R1 and R2 are H, and n is an integer from 4 to 42.

Description

Silicone hydrogel mixtures and the resulting wettable silicone hydrogel lenses Technical Field

[0001] This invention relates to a silicone hydrogel lens, and more particularly to a silicone hydrogel mixture and a wettable silicone hydrogel lens that is wettable without the need for a surface modification process. Background Technology

[0002] Contact lenses adhere directly to the cornea of ​​the eye, which requires a sufficient supply of oxygen to maintain its health. The cornea itself lacks blood vessels and obtains oxygen from the dissolved oxygen in the tear film on its surface. Contact lenses can block the contact between tears and air, reducing the dissolved oxygen content of the tears. Furthermore, prolonged wear of contact lenses can affect tear secretion, causing dry eyes and even leading to eye problems such as dry eye syndrome and keratitis. Therefore, the oxygen permeability and moisture content of contact lenses are crucial for eye health.

[0003] Traditional hydrogel contact lenses are primarily made of poly(hydroxyethyl methacrylate) (poly-HEMA), which has a high hydrophilicity. Their oxygen permeability (Dk / t) is approximately 20-30, which can easily cause corneal hypoxia with prolonged wear, leading to the aforementioned eye problems. To improve the oxygen permeability of contact lenses, silicone hydrogel lenses have been developed. Silicone hydrogels incorporate silicone into the hydrogel material. Silicone molecules create pores within the material, allowing oxygen to pass through, thus resulting in high oxygen permeability. Silicone hydrogel contact lenses can achieve oxygen permeability exceeding 100 Dk / t, making them more suitable for extended wear. Their high oxygen permeability can reduce the likelihood of eye problems such as keratitis.

[0004] However, silicone hydrogel itself is a hydrophobic material, and its surface is not easily wetted. Wearing contact lenses made of hydrophobic materials directly can cause eye discomfort and has problems such as easy absorption of lipids and protein deposition. To solve this problem, various methods have been developed to modify the surface of silicone hydrogel lenses, such as surface coating, chemical adsorption, or plasma technology, to adsorb hydrophilic components onto the surface of the silicone hydrogel lens, making the surface of the silicone hydrogel lens wettable.

[0005] However, these surface modification methods are too complex and costly. To simplify the process and reduce costs, the industry has developed a method of adding hydrophilic components during the lens material manufacturing process, making the resulting lens material itself wettable and eliminating the need for additional surface modification processes.

[0006] However, the surface hydrophilicity of existing wettable silicone hydrogel lenses still needs improvement. In order to provide users with a more comfortable wearing experience and extend the wearing time, the industry still needs a technical solution that can improve the surface hydrophilicity of silicone hydrogel lenses. Summary of the Invention

[0007] Therefore, improving the hydrophilicity of silicone hydrogel lens surfaces to provide users with a more comfortable wearing experience and extend wearing time is an important issue for the industry. In view of this, to address the aforementioned issues, the inventors of this project conducted extensive research and experiments to achieve the goal of providing silicone hydrogel lenses with higher surface hydrophilicity.

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

[0009] To achieve the above objectives, the present invention provides a silicone hydrogel mixture for forming wettable silicone hydrogel lenses, comprising a polysiloxane macromolecule, a hydrophilic polymer, and a hydrophilic non-polysiloxane crosslinking agent, wherein the hydrophilic non-polysiloxane crosslinking agent is polyethylene glycol dimethacrylate (PEGDMA), which has the following structural formula represented by formula (A):

[0010] Wherein, R1 and R2 are CH3 or H, and n is preferably an integer from 4 to 42.

[0011] Furthermore, the present invention provides a wettable silicone hydrogel lens, which is formed from the aforementioned silicone hydrogel mixture.

[0012] In practice, the content of polyethylene glycol dimethacrylate (PEGDMA) is 2-15% by weight of the silicone hydrogel mixture.

[0013] In practice, the wettable silicone hydrogel lens preferably has a dynamic contact angle of less than or equal to 50°.

[0014] Compared to existing technologies, the wettable silicone hydrogel lens made from the silicone hydrogel mixture provided in this case has a smaller droplet contact angle, which does improve the surface hydrophilicity of the lens. Detailed Implementation

[0015] This invention relates to a silicone hydrogel mixture for forming wettable silicone hydrogel lenses. The silicone hydrogel mixture of this invention comprises: a polysiloxane macromolecule, a hydrophilic polymer, and a hydrophilic non-polysiloxane crosslinking agent, wherein the hydrophilic non-polysiloxane crosslinking agent is polyethylene glycol dimethacrylate (PEGDMA), having the following structural formula represented by formula (A):

[0016] Where R1 and R2 are CH3 or H, and n is preferably an integer from 4 to 42.

[0017] Furthermore, the present invention provides a wettable silicone hydrogel lens, which is formed from the silicone hydrogel mixture described above.

[0018] In some embodiments, the content of polyethylene glycol dimethacrylate (PEGDMA) is 2 to 15% by weight of the silicone hydrogel mixture.

[0019] In some embodiments, the content of the polysiloxane macromolecules is preferably 5-50% by weight of the silicone hydrogel mixture, more preferably 15-50% by weight, or even more preferably 25-50% by weight.

[0020] In some embodiments, the polysiloxane macromolecule comprises (3-methacryloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (SiGMA), which has the following structural formula represented by formula (B):

[0021] The preferred content of (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (SiGMA) is 5-40% by weight of the silicone hydrogel mixture.

[0022] In some embodiments, the hydrophilic polymer may be polyvinylpyrrolidone (PVP), and the content of PVP is preferably 0.1 to 10% by weight of the silicone hydrogel mixture.

[0023] The average molecular weight of polyvinylpyrrolidone (PVP) is determined by gel permeation chromatography (GPC), and the measured average molecular weight is usually expressed as a K value. The K value of the PVP used in this invention is 90.

[0024] In the aforementioned silicone hydrogel mixture, the three-dimensional network formed by polyvinylpyrrolidone (PVP) molecular chains and polysiloxane macromolecules can form interpenetrating polymer network (IPN) structures and / or semi-interpenetrating polymer network (semi-IPN) structures. An interpenetrating polymer network (IPN) is a structure formed by two or more polymer network structures that are at least partially interpenetrating at the polymer scale. The polymer network structure is formed by covalently bonded polymers, while there are no covalent bonds between the polymers in the interpenetrating network. Nevertheless, IPN structures are difficult to separate unless the chemical bonds in the network structure are broken. Furthermore, there are also so-called semi-interpenetrating polymer network (semi-IPN) structures, characterized by comprising one or more networks interpenetrating with one or more linear or branched polymers at the polymer scale, with no covalent bonds between the interpenetrating polymers.

[0025] In some embodiments, the silicone hydrogel mixture may contain another hydrophilic polymer that can form polymer entanglement with polyvinylpyrrolidone (PVP) in the aforementioned IPN or semi-IPN structure, thereby making the PVP more stable and less prone to detachment from the IPN or semi-IPN structure. Polymer entanglement refers to the network or spherical structure formed by crosslinking points within or between polymer chains, which prevents the polymer chains from moving normally and thus affects the properties of the polymer.

[0026] In some embodiments, the other hydrophilic polymer may be polymerized from N-vinyl-2-pyrrolidinone (NVP) monomer, and its content is preferably 5 to 40% by weight of the silicone hydrogel mixture.

[0027] The wettability (hydrophilicity) of a material surface is usually determined by the angle formed by the liquid / gas interface of a droplet on the material surface. This angle is generally called the dynamic contact angle (DCA). The smaller the dynamic contact angle, the more hydrophilic the material surface is. The dynamic contact angle of a hydrophobic material surface is greater than 90°.

[0028] The wettable silicone hydrogel lens formed from the above-mentioned silicone hydrogel mixture preferably has a dynamic contact angle of less than or equal to 70°, more preferably a dynamic contact angle of less than or equal to 60°, or even more preferably a dynamic contact angle of less than or equal to 50°.

[0029] The following examples illustrate the composition and effects of the mixtures of the present invention, but these examples are not intended to limit the invention. The compound abbreviations used in the examples are listed in Table 1.

[0030] Table 1

[0031] Tables 2 and 3 list the reaction components and results of the silicone hydrogel mixtures in Examples 1 to 11, where Examples 1 to 7 are comparative examples, and Examples 8 to 11 are embodiments of the present invention. The units of content of each reaction component listed in the tables are weight percentages.

[0032] Table 2

[0033] Table 3

[0034] The examples of silicone hydrogel lenses listed in Tables 2 and 3 were prepared as follows: The reactive components and diluent (TAA) were mixed at approximately 23°C by stirring or rolling for at least 12 hours until all components dissolved. The content of the reactive components was expressed as a weight percentage of the mixture of all reactive components except for the diluent (TAA) and dye (RB246), while the content of the diluent (TAA) and dye (RB246) was expressed as a weight percentage of the final reaction mixture. The mixed reaction mixture was placed in a thermoplastic contact lens mold and then cured. The curing process included the following steps: first, rinsing in nitrogen for 1 hour; then, heating to 90°C at a rate of 45°C per minute; and then curing at 90°C for 24 hours. The oxygen concentration in the curing oven was preferably less than 500 ppm, more preferably less than 100 ppm. After the curing process was completed, the mold was opened, the cured lens was removed, and placed in a borate buffer solution. The lens was then immersed in the borate buffer solution at 80°C for 3 hours to remove residual monomers and diluent. The characteristics of the completed lenses are listed below in Tables 2 and 3.

[0035] Tables 2 and 3 list the three properties of the completed lens that were tested: dynamic contact angle (DCA), oxygen permeability (Dk), and visible light transmittance (VLT).

[0036] Dynamic contact angle (DCA) is measured using the DSA25 droplet shape analyzer. Optronic measurements were taken using a contact lens adapter, with the lenses stored and tested in borate buffer. Oxygen permeability was measured using a Rhder O2 Permeometer model 201T, according to the method described in international standard ISO 9913-1. Visible light transmittance (VLT) was measured using a spectral transmittance meter.

[0037] The main difference between Examples 1 to 6 (comparative examples) lies in the different amounts of DMA, HEMA, and PVP in the reaction components. Table 2 below lists the test results for the lenses of Examples 1 to 6. The results show that increasing the HEMA content can improve the visible light transmittance of the lens.

[0038] Table 3 lists Examples 8 to 11. For ease of comparison, Examples 6 to 7 (comparative examples) are also listed in Table 3. The main difference in the formulations of the mixtures in Examples 6 to 11 is the use of non-polysiloxane crosslinking agents with different degrees of polymerization (n). The crosslinking agent used in Example 6 (Comparative Example) is EGDMA (n=1), the crosslinking agent used in Example 7 (Comparative Example) is TEGDMA (n=3), and the crosslinking agents used in Examples 8 to 11 are PEGDMA330 (n=4), PEGDMA550 (n=9), PEGDMA750 (n=14), and PEGDMA2000 (n=42), respectively. The test results listed in Table 3 show that the silicone hydrogel lenses provided in Examples 8 to 11 have good performance in various property tests, including good contact angle, appropriate oxygen permeability, and transparency. In particular, the dynamic contact angle test results show that, compared with Examples 1 to 7, the dynamic contact angles of Examples 8 to 11 are all less than 50°, which is significantly lower than the dynamic contact angles measured in Examples 1 to 7. This shows that the silicone hydrogel mixture provided in this case can obviously improve the hydrophilicity of the lens.

[0039] Therefore, the silicone hydrogel mixture and the wettable silicone hydrogel lens made from the mixture provided by the present invention can achieve the purpose of the present invention, have better hydrophilicity, effectively improve the wettability of the lens surface, thus providing users with a more comfortable wearing experience and extending the wearing time.

[0040] Furthermore, the wettable silicone hydrogel lens provided by this invention can effectively reduce the use of organic solvents in the manufacturing process and greatly simplify the recycling process of waste organic solvents. Therefore, its manufacturing process is not only more environmentally friendly, but also reduces costs.

[0041] The above detailed description represents a preferred embodiment of the present invention, and its formulation ratios and process conditions are not readily available to those skilled in the art. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described above. Therefore, those skilled in the art can make appropriate changes or improvements to the following embodiments based on their knowledge in the art, without departing from the scope of the present invention.

Claims

1. A silicone hydrogel mixture for forming wettable silicone hydrogel lenses, characterized in that, This silicone hydrogel mixture contains: Polysiloxane macromolecules; Hydrophilic polymers: and A hydrophilic non-polysiloxane crosslinking agent, wherein the hydrophilic non-polysiloxane crosslinking agent is polyethylene glycol dimethacrylate (PEGDMA), which has the following structural formula represented by formula (A): Where R1 and R2 are CH3 or H, and n is an integer from 4 to 42.

2. The silicone hydrogel mixture as described in claim 1, wherein, The content of the polysiloxane macromolecule is 5-50% by weight of the silicone hydrogel mixture.

3. The silicone hydrogel mixture as described in claim 1, wherein, The polysiloxane macromolecule comprises (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (SiGMA), which has the following structural formula represented by formula (B): Furthermore, the content of (3-methacryloyloxy-2-hydroxypropoxy)propylbis(trimethylsiloxy)methylsilane (SiGMA) is 5-40% by weight of the silicone hydrogel mixture.

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

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

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

7. The silicone hydrogel mixture of claim 6, wherein, The hydrophilic polymer further comprises a second hydrophilic polymer, which forms polymer entanglement with the first hydrophilic polymer in the interpenetrating polymer network structure and / or semi-interpenetrating polymer network structure.

8. The silicone hydrogel mixture of claim 4, wherein, The hydrophilic polymer further comprises a second hydrophilic polymer, which is polymerized from 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 of claim 1, wherein, The content of polyethylene glycol dimethacrylate (PEGDMA) is 2-15% by weight of the silicone hydrogel mixture.

10. A wettable silicone hydrogel lens, formed from a silicone hydrogel mixture as claimed in any one of claims 1 to 8.

11. The wettable silicone hydrogel lens as described in claim 10, wherein, This wettable silicone hydrogel lens has a dynamic contact angle of less than or equal to 50°.

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