Silicone hydrogel contact lens capable of being mechanically demoulded and preparation method thereof

Abstract

The invention belongs to the technical field of contact lenses, and particularly discloses a silicone hydrogel contact lens capable of being mechanically demoulded. The silicone hydrogel contact lens capable of being mechanically demoulded is prepared by heating and reacting 5-20 parts of dimethylaminoethyl methacrylate, 20-60 parts of hydrophilic monomer, 1.5-3 parts of polyethylene glycol monomethyl ether, 10-20 parts of siloxane monomer, 0.5-2 parts of cross-linking agent and 0.5-2 parts of polymerization initiator, and then performing mechanical demoulding. The proportion of the added siloxane monomer is moderate, so that the oxygen permeability of the lens is ensured, and the wearing comfort of the lens is not influenced; the polyethylene glycol monomethyl ether is added to form crosslinking with other components, so that the toughness of the silicone hydrogel contact lens is remarkably improved, the damage of mechanical demolding to the lens is reduced, and the success rate of mechanical demolding is increased.

Description

Technical Field

[0001] The invention relates to the technical field of contact lenses, and in particular to a mechanically demouldable silicone hydrogel contact lens and a preparation method thereof. Background Art

[0002] Silicone hydrogel contact lenses have won wide market recognition and consumer favor with their unique material advantages and good wearing experience. This type of contact lens combines the high oxygen permeability of silicone materials with the hydrophilicity of hydrogels, bringing a comfortable wearing experience and good visual health protection to the wearer.

[0003] At present, the molding method of silicone hydrogel contact lenses mainly relies on advanced manufacturing processes, among which the most common and mature molding methods are injection molding and lathe cutting. The lathe cutting method has problems such as low production efficiency, high cost, difficulty in precision control and limited scope of application; while the injection molding method has problems such as difficult demolding and complex post-processing. Silicone hydrogel contact lenses are soft after curing, not easy to demold mechanically, and have a low demolding yield, and have high requirements for demolding equipment or demolding processes; at the same time, there is also the problem of complex post-processing. The produced lenses need to go through multiple post-processing steps, such as alcohol washing, water washing, soaking, etc., to remove residues and sterilize. These processes require strict control of conditions and time to ensure the quality and safety of the lenses.

[0004] In response to the above problems, existing research usually adopts the method of increasing the hardness of silicone hydrogel contact lenses to achieve mechanical demolding of contact lenses, but this method often requires increasing the addition of silicon-containing components. At the same time, increasing the hardness will also reduce the wearing comfort of the contact lenses, diluting the comfort characteristics of silicone hydrogel contact lenses.

[0005] Therefore, how to provide a silicone hydrogel contact lens that can be mechanically demolded and a preparation method thereof, while ensuring a high mechanical demolding yield rate and maintaining the softness and good wearing comfort of the silicone hydrogel contact lens is a difficult problem that needs to be solved urgently in the art. Summary of the invention

[0006] In view of this, the present invention provides a mechanically demoldable silicone hydrogel contact lens and a preparation method thereof, so as to solve the problem that silicone hydrogel contact lenses are not suitable for mechanical demolding and the existing silicone hydrogel contact lenses that can support mechanical demolding have too high hardness.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A mechanically demouldable silicone hydrogel contact lens is prepared from raw materials comprising the following parts by mass:

[0009] 5 to 20 parts of dimethylaminoethyl methacrylate, 20 to 60 parts of hydrophilic monomer, 1.5 to 3 parts of polyethylene glycol monomethyl ether, 10 to 20 parts of siloxane monomer, 0.5 to 2 parts of crosslinking agent, and 0.5 to 2 parts of polymerization initiator.

[0010] Preferably, the siloxane monomer includes one or more of divinyl-terminated polydimethylsiloxane, γ-methacryloxypropyltrimethoxysilane and methacryloxypropyltris(trimethylsiloxy)silane.

[0011] Preferably, the molecular weight of the polyethylene glycol monomethyl ether is 3000-5000 Da.

[0012] Preferably, the hydrophilic monomer includes one or more of 2-hydroxyethyl methacrylate, N-vinyl pyrrolidone, butyl methacrylate and N,N-dimethylacrylamide.

[0013] Preferably, the crosslinking agent includes one or more of ethylene glycol dimethacrylate, triallyl 1,3,5-cyanurate, divinylbenzene, triethylene glycol dimethacrylate, triethylene glycol divinyl ester, divinyl glycol ester, polyethylene glycol dimethacrylate, divinyl polyethylene glycol ester and polyethylene glycol vinyl methacrylate.

[0014] Preferably, the polymerization initiator includes one or more of azobisisobutyronitrile, benzoyl oxide, azobisisoheptanenitrile and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0015] Another object of the present invention is to provide a method for preparing a mechanically demouldable silicone hydrogel contact lens, comprising the following steps:

[0016] Dimethylaminoethyl methacrylate, hydrophilic monomer, polyethylene glycol monomethyl ether, siloxane monomer, crosslinking agent and polymerization initiator are mixed, reacted in a mold, and then mechanically demolded to obtain a silicone hydrogel contact lens.

[0017] Preferably, the reaction includes a first heating reaction and a second heating reaction;

[0018] The temperature of the first heating reaction is 50-60°C, and the time of the first heating reaction is 20-30 minutes;

[0019] The temperature of the second heating reaction is 80-120° C., and the time of the second heating reaction is 1.5-2 hours.

[0020] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The main component in silicone hydrogel contact lenses that increases the hardness of the lenses is silicon. By adding silicon, natural pores are created between the silicone hydrogel materials. These pores allow oxygen to pass freely, thereby significantly improving the oxygen permeability of the lenses, which is beneficial to contact lenses. However, silicon molecules themselves have a certain hardness. Therefore, as the oxygen permeability value increases, the material hardness of silicone hydrogel lenses will also increase accordingly. If the hardness is too high, the comfort of the contact lenses will decrease. The present invention limits the amount of each component added and discloses the specific number of siloxane monomers added. The proportion of siloxane monomers in the silicone hydrogel contact lenses disclosed in the present invention is moderate, and no excessive amount of siloxane monomers is added. While ensuring the oxygen permeability of the lenses, it will not affect the wearing comfort of the lenses.

[0022] 2. The present invention also discloses the addition of polyethylene glycol monomethyl ether. The macromolecular polyethylene glycol monomethyl ether can form cross-links with other components, which significantly improves the toughness of the silicone hydrogel contact lens and reduces the damage to the lens caused by mechanical demoulding;

[0023] 3. The contact lens prepared by the present invention can support mechanical demoulding, and due to its high toughness, the success rate of mechanical demoulding is improved. DETAILED DESCRIPTION

[0024] The present invention provides a mechanically demouldable silicone hydrogel contact lens, which is prepared from raw materials containing the following mass parts:

[0025] 5 to 20 parts of dimethylaminoethyl methacrylate, 20 to 60 parts of hydrophilic monomer, 1.5 to 3 parts of polyethylene glycol monomethyl ether, 10 to 20 parts of siloxane monomer, 0.5 to 2 parts of cross-linking agent, 0.5 to 2 parts of polymerization initiator; preferably, 8 to 15 parts of dimethylaminoethyl methacrylate, 30 to 50 parts of hydrophilic monomer, 1.8 to 2.5 parts of polyethylene glycol monomethyl ether, 12 to 18 parts of siloxane monomer, 0.8 to 1.5 parts of cross-linking agent, 0.8 to 1.5 parts of polymerization initiator; further preferably, 10 parts of dimethylaminoethyl methacrylate, 40 parts of hydrophilic monomer, 2 parts of polyethylene glycol monomethyl ether, 15 parts of siloxane monomer, 1 part of cross-linking agent, 1 part of polymerization initiator.

[0026] In the present invention, the siloxane monomer includes one or more of divinyl-terminated polydimethylsiloxane, γ-methacryloxypropyltrimethoxysilane and methacryloxypropyltris(trimethylsiloxy)silane.

[0027] In the present invention, the molecular weight of the polyethylene glycol monomethyl ether is 3000-5000 Da, specifically 3200 Da, 3400 Da, 3500 Da, 3600 Da, 3800 Da, 4000 Da, 4200 Da, 4500 Da, 4600 Da, and 4800 Da.

[0028] In the present invention, the hydrophilic monomer includes one or more of 2-hydroxyethyl methacrylate, N-vinyl pyrrolidone, butyl methacrylate and N,N-dimethylacrylamide.

[0029] In the present invention, the crosslinking agent includes one or more of ethylene glycol dimethacrylate, triallyl 1,3,5-cyanurate, divinylbenzene, triethylene glycol dimethacrylate, triethylene glycol divinyl ester, divinyl glycol ester, polyethylene glycol dimethacrylate, divinyl polyethylene glycol ester and polyethylene glycol vinyl methacrylate.

[0030] In the present invention, the polymerization initiator includes one or more of azobisisobutyronitrile, benzoyl oxide, azobisisoheptanenitrile and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0031] The present invention also provides a method for preparing a mechanically demouldable silicone hydrogel contact lens, comprising the following steps:

[0032] Dimethylaminoethyl methacrylate, hydrophilic monomer, polyethylene glycol monomethyl ether, siloxane monomer, crosslinking agent and polymerization initiator are mixed, reacted in a mold, and then mechanically demolded to obtain a silicone hydrogel contact lens.

[0033] In the present invention, the reaction includes a first heating reaction and a second heating reaction.

[0034] In the present invention, the temperature of the first heating reaction is 50-60°C, specifically 52°C, 54°C, 55°C, 56°C, 58°C; the time of the first heating reaction is 20-30min, specifically 22min, 24min, 25min, 26min, 28min.

[0035] The temperature of the second heating reaction is 80-120°C, specifically 82°C, 85°C, 88°C, 100°C, 102°C, 105°C, 108°C, 110°C, 112°C, 115°C, 118°C; the time of the second heating reaction is 1.5-2h, specifically 1.6h, 1.7h, 1.8h, 1.9h.

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] 10 parts of dimethylaminoethyl methacrylate, 40 parts of 2-hydroxyethyl methacrylate, 2 parts of polyethylene glycol monomethyl ether (3000-4000Da), 6 parts of divinyl-terminated polydimethylsiloxane, 6 parts of γ-methacryloxypropyl trimethoxysilane, 1 part of ethylene glycol dimethacrylate and 1 part of azobisisobutyronitrile were fully mixed, and after mixing, the mixture was injected into the contact lens mold and molded. Then, the nitrogen atmosphere was adjusted, and the temperature was heated at 60°C for 25 minutes, and then the temperature was adjusted to 100°C and heated for 2 hours to obtain a silicone hydrogel contact lens. The silicone hydrogel contact lens was separated from the mold by traditional mechanical demolding to obtain a dry lens.

[0039] The dry lenses were soaked in water for 12 hours, and then placed in a standard saline solution with a pH value of 7 and hydrated at 60° C. for 12 hours to obtain silicone hydrogel contact lenses.

[0040] Example 2

[0041] 20 parts of dimethylaminoethyl methacrylate, 20 parts of N-vinyl pyrrolidone, 1.5 parts of polyethylene glycol monomethyl ether (3500-4000Da), 10 parts of divinyl-terminated polydimethylsiloxane, 2 parts of triethylene glycol dimethacrylate and 1.5 parts of azobisisobutyronitrile were fully mixed, and after mixing, the mixture was injected into the contact lens mold and molded. Then, the nitrogen atmosphere was adjusted, and the temperature was heated at 50°C for 25 minutes, and then the temperature was adjusted to 100°C and heated for 1.5 hours to obtain a silicone hydrogel contact lens. The silicone hydrogel contact lens was separated from the mold by traditional mechanical demolding to obtain a dry lens.

[0042] The dry lenses were soaked in water for 12 hours, and then placed in a standard saline solution with a pH value of 7 and hydrated at 60° C. for 12 hours to obtain silicone hydrogel contact lenses.

[0043] Example 3

[0044] 8 parts of dimethylaminoethyl methacrylate, 60 parts of 2-hydroxyethyl methacrylate, 2.5 parts of polyethylene glycol monomethyl ether (4000-5000Da), 10 parts of divinyl-terminated polydimethylsiloxane, 5 parts of methacryloyloxypropyl tris(trimethylsiloxy)silane, 0.5 parts of ethylene glycol dimethacrylate and 2 parts of azobisisobutyronitrile were fully mixed, and after mixing, the mixture was injected into the contact lens mold and molded. Then, the nitrogen atmosphere was adjusted, and the temperature was heated at 55°C for 30 minutes, and then the temperature was adjusted to 120°C and heated for 1.5 hours to obtain a silicone hydrogel contact lens, and the silicone hydrogel contact lens was separated from the mold by traditional mechanical demolding to obtain a dry lens.

[0045] The dry lenses were soaked in water for 12 hours, and then placed in a standard saline solution with a pH value of 7 and hydrated at 60° C. for 12 hours to obtain silicone hydrogel contact lenses.

[0046] Comparative Example 1

[0047] The difference between this comparative example and Example 1 is that the addition amount of polyethylene glycol monomethyl ether is adjusted to 1 / 2 of the original amount.

[0048] Comparative Example 2

[0049] The only difference between this comparative example and Example 1 is that the addition amount of the two siloxane monomers is doubled.

[0050] Experimental Example 1

[0051] The appearance, hardness, oxygen permeability, elongation and tensile strength of the silicone hydrogel contact lenses prepared in Examples 1 to 3 and Comparative Examples 1 to 2 were tested respectively.

[0052] Hardness: D-type Shore durometer; oxygen permeability: GB / T11417.7-2012, 201T oxygen permeability tester, Dk unit: 42×10 -11 (cm 2 / s)[mLO2 / (mL.hPa)]; Elongation and tensile strength: ANSI Z80.20-2016, Instron 3342, contact lenses are tested by cutting into rectangular samples symmetrically with respect to the center of the mold.

[0053] Table 1 Related performance test results

[0054]

[0055] It can be seen from Table 1 that the silicone hydrogel contact lenses obtained by the present invention have moderate hardness, transparent appearance, good oxygen permeability, and good wearing comfort. The present invention also tests the elongation and tensile strength of the silicone hydrogel contact lenses, which have relatively excellent elongation and high tensile strength, reflecting the characteristics of high toughness, and can ensure that the contact lenses are not damaged during the mechanical demolding process. Comparison between Example 1 and Comparative Example 1 shows that the addition of polyethylene glycol monomethyl ether can effectively improve the tensile strength and toughness of the contact lenses, and also has a certain effect on the hardness; subsequent tests also show that the addition of polyethylene glycol monomethyl ether can also help improve the hydrophilicity of the contact lenses, which is beneficial to eye health and wearing comfort. Compared with Comparative Example 2, it can be found that excessive addition of siloxane monomers will cause the hardness of the lenses to increase and reduce oxygen permeability.

[0056] Experimental Example 2

[0057] The steps for preparing the silicone hydrogel contact lenses of Examples 1 to 3 and Comparative Example 1 were repeated (500 times), and the qualified rate of the silicone hydrogel contact lenses after demolding was recorded.

[0058] Table 2 Mechanical demoulding qualification rate

[0059] Example 1 Example 2 Example 3 Comparative Example 1 Number of qualified 488 480 490 347 Pass rate / % 97.6 96 98 69.4

[0060] It can be seen from Table 2 that the invention significantly improves the mechanical demoulding qualified rate of silicone hydrogel contact lenses by adding polyethylene glycol monomethyl ether in a reasonable ratio, and successfully prepares silicone hydrogel contact lenses that can be mechanically demoulded.

[0061] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0062] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A mechanically demouldable silicone hydrogel contact lens, characterized in that: Prepared from the following raw materials in parts by weight: 5 to 20 parts of dimethylaminoethyl methacrylate, 20 to 60 parts of hydrophilic monomer, 1.5 to 3 parts of polyethylene glycol monomethyl ether, 10 to 20 parts of siloxane monomer, 0.5 to 2 parts of crosslinking agent, and 0.5 to 2 parts of polymerization initiator.

2. A mechanically demouldable silicone hydrogel contact lens according to claim 1, characterized in that: The siloxane monomer includes one or more of divinyl-terminated polydimethylsiloxane, γ-methacryloxypropyltrimethoxysilane and methacryloxypropyltri(trimethylsiloxy)silane.

3. A mechanically demouldable silicone hydrogel contact lens according to claim 2, characterized in that: The molecular weight of the polyethylene glycol monomethyl ether is 3000-5000 Da.

4. A mechanically demouldable silicone hydrogel contact lens according to any one of claims 1 to 3, characterized in that: The hydrophilic monomer includes one or more of 2-hydroxyethyl methacrylate, N-vinyl pyrrolidone, butyl methacrylate and N,N-dimethylacrylamide.

5. A mechanically demouldable silicone hydrogel contact lens according to claim 4, characterized in that: The crosslinking agent includes one or more of ethylene glycol dimethacrylate, triallyl 1,3,5-cyanurate, divinylbenzene, triethylene glycol dimethacrylate, triethylene glycol divinyl ester, divinyl glycol ester, polyethylene glycol dimethacrylate, divinyl polyethylene glycol ester and polyethylene glycol vinyl methacrylate.

6. The mechanically demouldable silicone hydrogel contact lens according to claim 5, characterized in that: The polymerization initiator includes one or more of azobisisobutyronitrile, benzoyl oxide, azobisisoheptanenitrile and 2-hydroxy-2-methyl-1-phenyl-1-propanone.

7. The method for preparing a mechanically demouldable silicone hydrogel contact lens according to any one of claims 1 to 6, characterized in that: The steps include: Dimethylaminoethyl methacrylate, hydrophilic monomer, polyethylene glycol monomethyl ether, siloxane monomer, crosslinking agent and polymerization initiator are mixed, reacted in a mold, and then mechanically demolded to obtain a silicone hydrogel contact lens.

8. The method for preparing a mechanically demouldable silicone hydrogel contact lens according to claim 7, characterized in that: The reaction includes a first heating reaction and a second heating reaction; The temperature of the first heating reaction is 50-60°C, and the time of the first heating reaction is 20-30 minutes; The temperature of the second heating reaction is 80-120° C., and the time of the second heating reaction is 1.5-2 hours.

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