Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D11/00—Producing optical elements, e.g. lenses or prisms
  • B29D11/00009—Production of simple or compound lenses
  • B29D11/00038—Production of contact lenses
  • B29D11/00125—Auxiliary operations, e.g. removing oxygen from the mould, conveying moulds from a storage to the production line in an inert atmosphere
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C33/00—Moulds or cores; Details thereof or accessories therefor
  • B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
  • B29C33/60—Releasing, lubricating or separating agents
  • B29C33/62—Releasing, lubricating or separating agents based on polymers or oligomers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
  • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
  • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
  • B29C35/0888—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using transparant moulds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C37/00—Component parts, details, accessories or auxiliary operations, not covered by group B29C33/00 or B29C35/00
  • B29C37/0025—Applying surface layers, e.g. coatings, decorative layers, printed layers, to articles during shaping, e.g. in-mould printing
  • B29C37/0028—In-mould coating, e.g. by introducing the coating material into the mould after forming the article
  • B29C37/0032—In-mould coating, e.g. by introducing the coating material into the mould after forming the article the coating being applied upon the mould surface before introducing the moulding compound, e.g. applying a gelcoat
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
  • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
  • B29C35/08—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation
  • B29C35/0805—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation
  • B29C2035/0827—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould by wave energy or particle radiation using electromagnetic radiation using UV radiation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2011/00—Optical elements, e.g. lenses, prisms
  • B29L2011/0016—Lenses
  • B29L2011/0041—Contact lenses

Definitions

• the present invention relates to a process for the pretreatment of reusable UV-curable moulds, used, for example, for the production of ophthalmic mouldings such as contact lenses, by applying a solution of a particular tenside to the lens surface.
• U.S. Patent No. 5,583,163 describes the manufacture of mouldings such as in particular contact lenses by crosslinking an aqueous solution of a water-soluble polyvinyl alcohol prepolymer in a mould.
• the process according to US 5,583,163 may be performed using moulds made from polypropylene, quartz, sapphire, glass or the like. Suitable reusable moulds are, for example, quartz or glass moulds.
• Contact lenses manufactured according to the process of the prior art patent have advantageous properties, such as good compatibility with the human cornea, resulting in a high wearing comfort and the absence of irritation and allergenic effects.
• problems may sometimes show up in production.
• cracks, flaws or tears may occur in the lenses. In the worst case the contact lenses even break totally. Contact lenses having such defects have to be discarded and lower the overall production yield.
• EP 0 765 733 describes a method for the modification of the surface energy of hydrophobic contact lens moulds composed essentially of polystyrene to improve wettability and release characteristics by coating the surfaces of said moulds with a surfactant, prior to contact of said mould with the reactive monomer mixture.
• the preferred surfactant is polysorbate 20, which is basically a polyethylene oxide sorbitan mono-oleate, commercially available, e.g. under the trade name Tween 80 ® .
• the invention relates to a process for the pretreatment of contact lens moulds comprising the following steps:
• the invention relates to a process for the manufacture of a moulding comprising the following steps:
• the process is particularly useful for, but not restricted to, the manufacture of opththalmic lenses such as, for example, contact lenses and intraocular lenses. It is preferred to repeat steps (a) to (f) in a cycle.
• Preferred poly(oxyethylene)-po!y(oxypropylene) block copolymers (PEO-PPO, where "PEO” is poly(ethylene oxide) and “PPO” is poly(propyIene oxide) used in the inventive process are block copolymers which are derived from the sequential addition of propylene oxide and ethylene oxide to a difunctional alcohol or amine. More preferred tensides are block copolymers of formula
• i, j, x and y each have values from 2 to 400.
• Triblock copolymers PEO-PPO-PEO of formula (I) are called poloxamers. They are obtained by the controlled addition of propylene oxide to the two hydroxyl groups of propylene glycol followed by the addition of ethylene oxide. Poloxamers are available, for example, under the tradename PLURONIC ® or SYNPERONIC ® . A various number of poloxamers is known, differing in the molecular weight and in the PEO/PPO ratio.
• Examples are poloxamer 101 , 105, 108, 122, 123, 124, 181 , 182, 183, 184, 185, 188, 212, 215, 217, 231 , 234, 235, 237, 238, 282, 284, 288, 331 , 333, 334, 335, 338, 401 , 402, 403 and 407.
• the ratio of PEO/PPO may vary between wide limits.
• polyoxyethylene and polyoxypropylene blocks can be reversed creating block copolymers with the structure PPO-PEO-PPO (II), which are known as PLURONIC-R ® polymers.
• Tetrafunctional poly(oxyethylene)-poly(oxypropylene) block copolymers of formula (III), which are known under the trade name TETRONIC ® may be obtained by the sequential addition of propylene oxide and ethylene oxide to ethylenediamine. Again, the order of polyoxyethylene and polyoxypropylene blocks can be reversed creating block copolymers of formula (IV), commercially available, for example, as TETRONIC-R® polymers.
• Polyoxypropylene-polyoxyethylene block copolymers can also be designed with hydrophilic blocks comprising a random mix of ethylene oxide and propylene oxide repeating units. To maintain the hydrophilic character of the block, ethylene oxide will predominate. Similarly, the hydrophobic block can be a mixture of ethylene oxide and propylene oxide repeating units. Such block copolymers are available under the trade name PLURADOT ® .
• a particularly preferred group of poly(oxyethylene)-poly(oxypropylene) block copolymers used in step (a) of the present invention are poloxamers of formula (I) of any PEO/PPO ratio having a number average molecular weight of from about 3,000 to about 15,000 and tetrafunctional tensides of formula (III) having a number average molecular weight of from about 10,000 to about 30,000.
• the non-ionic tenside may be applied in step (a) of the process of the invention per se or preferably in solution.
• Preferred solvents for the preparation of the solution of the tenside according to step (a) are water, C C 4 -alkanols, C 2 -C 6 -dialkylethers, C 3 -C 5 -ketones and mixtures thereof. Water and water/C ⁇ -C -alkanol mixtures are preferred.
• the solution in step (a) comprises, based on the entire weight of the solution, 0.01 to 3 % (w/w), preferably 0.02 to 0.5 % (w/w), and more preferably 0.05 to 0.3 % (w/w) and in particular 0.1 to 0.25 % (w/w) of the non-ionic tenside.
• the solution of the non-ionic tenside may be applied to the mould surface by any known method, for example, by spraying, swabbing, dipping or stamping such that the surface is evenly coated therewith. Spraying using a spray nozzle is preferred.
• steps (a) and (b) may vary within wide limits readily discemable by a person skilled in the art. Surprisingly, we have found that even with very short processing times for step (a) and/or (b), for example, less than 10 seconds, used in today's contact lens production, particularly favourable results may be been obtained.
• the process of the present invention is especially useful in, but not restricted to, the manufacturing of ophthalmic mouldings by polymerizing a solution of a water-soluble prepolymer having crosslinkable groups.
• the water-soluble prepolymer having crosslinkable groups is a derivative of a polyvinyl alcohol (PVA) having a molecular weight of at least about 2 000 that, based on the number of hydroxy groups of the polyvinyl alcohol, comprises from about 0.5 to about 80 % of units of formula
• R is C ⁇ -C 8 -alkylene
• R 1 is hydrogen or d-C 7 -alkyl
• R 2 is an olefinically unsaturated, electron-attracting, copolymerizable radical preferably having up to 25 carbon atoms.
• Preferred PVA materials are disclosed in US 5,583,163.
• R 2 in formula (V) is -[CO-NH-(R 5 -NH-CO-O) q -R 6 -O-] p -CO-R 4 , wherein R 4 is an olefinically unsaturated copolymerizable radical having from 2 to 8 carbon atoms, and R 5 and R 6 are each independently lower alkylene having from 2 to 8 carbon atoms, arylene having from 6 to 12 carbon atoms, a saturated divalent cycloaliphatic group having from 6 to 10 carbon atoms, arylenealkylene or alkylenearylene having from 7 to 14 carbon atoms or arylenealkylenearylene having from 13 to 16 carbon atoms. Particularly preferred are units of formula (V), wherein R is methylene, R 1 is hydrogen and R 2 is acryloyl.
• the pre-treatment according to the present invention materially improves release characteristics of contact lenses from reusable quartz or glass moulds. Due to a decreased adherence of the contact lens to the mould surface, the mechanical stress on the contact lens during the mould opening is lowered. The reduced mechanical stress in turn results in a decreased rate of damaged contact lenses. Accordingly, the overall yield of contact lenses of acceptable quality in the process of the invention is considerably increased relative to the process as disclosed in U.S. Patent No. 5,583,163.
• a further benefit of the pretreatment of reusable quartz or glass lens moulds according to the present invention is that the lens moulds may be easily cleaned after removal of the mouldings from the mould, thereby making the mould with less effort ready for a next cycle comprising steps (a) to (f).
• Reusable glass lens moulds (made from glass of type BK-7) are sprayed during 4 seconds with about 40 ⁇ L of a 0.1 % (w/w) aqueous solution of the specific tenside, followed by 4 seconds of drying by an air jet.
• An aqueous prepolymer solution prepared according to US 5,583,163, Example 15 (i), is transferred to the moulds.
• the lenses are then irradiated for about 10 seconds using a 200 W Oriel UV lamp (150 mW/cm 2 ).
• the moulds are then opened and the separation forces measured with the tensile test machine. Table

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• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Toxicology (AREA)
• Physics & Mathematics (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Manufacturing & Machinery (AREA)
• Eyeglasses (AREA)
• Encapsulation Of And Coatings For Semiconductor Or Solid State Devices (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Polyethers (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)
• Manufacture Of Switches (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (7)

Cited By (5)

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Citations (7)

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• 2003
  • 2003-05-07 US US10/431,151 patent/US20030209818A1/en not_active Abandoned
  • 2003-05-12 WO PCT/EP2003/004947 patent/WO2003095171A1/en not_active Ceased
  • 2003-05-12 DE DE60307826T patent/DE60307826T2/de not_active Expired - Lifetime
  • 2003-05-12 AT AT03727470T patent/ATE337149T1/de not_active IP Right Cessation
  • 2003-05-12 JP JP2004503230A patent/JP4318636B2/ja not_active Expired - Fee Related
  • 2003-05-12 AU AU2003233321A patent/AU2003233321A1/en not_active Abandoned
  • 2003-05-12 EP EP03727470A patent/EP1507639B1/en not_active Expired - Lifetime

Patent Citations (7)

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