DE19900492A1 - Production of silane-based hydrophilic coatings on polymer surfaces giving articles useful in food technology, water treatment, biotechnology, hygiene and medicine - Google Patents

Abstract

Production of a hydrophilic coating on a polymeric substrate involves treating with a specified silane derivative and then with a hydrophilic (or latently hydrophilic) compound, the substrate being surface-structured after treatment with the silane derivative. The silane derivative is of formula (I). (Y(R<1>Z)mR<2>)nSiR<3>X4-n-0 (I) o = 0-2; n = 0-(3-0); m = 0-5; R<1> - R<3> = 1-12C alkyl, 2-12C alkenyl, phenyl or phenylalkyl with R<2> and R<3> same as or different to R<1>; Y = HS-, H2N-, HR<1>N-, (R<1>)2N-, Cl-, Br-, I-, -CN, R<1>S-, -SO2Cl, -NCO, -CO2R<1>, -SCN or an epoxy group of formula (II); Z = -S-, -O-, -R<1>N- or -HN-; X = F-, Cl-, Br-, I-, R<4>O-, HO-, H- or -N(R<1>)2; and R<4> = 1-6C alkyl, 2-8C alkoxy, 5-7C cycloaliphatic group, -C(O)R<1>, -Si(CH3)3, phenyl or phenylalkyl.

Description

The invention relates to a method for permanently hydrophilic coating of polymeric substrates, the use of the coated polymeric substrates and Products made from the coated polymeric substrates.

Polymers used in physiologically sensitive areas such as the eyes different properties have to be combined. So z. B. Contact lenses in addition to good optical properties such. B. high transparency and high refractive index have a number of other properties to make it Support the eye permanently and not damage it. The lenses should look preferably adapt to the eye as flexibly as possible, be chemically inert and be one have a high wearing comfort, so that irritation of the eye even with long No wearing times.

Irritation of the eye is usually caused by insufficient oxygen supply to the Cornea (cornea) or by mechanical stress on the cornea what e.g. B. can occur in hard contact lenses. A bad one too Wettability of the lens material by the tear fluid leads to intolerances in the eye. The lack of hydrophilicity means that the surface of the lens is not is wetted and leads to tearing of the tear film. For undistorted vision To ensure the film must remain intact. The tear film on the cornea of the human eye also acts as a protection against one by the Contact lenses caused friction. Tearing the film therefore leads to Irritation and a reduction in the wear time of the contact lens.

Among the various materials for contact lenses that required them Polysiloxanes in particular have largely combined properties exposed.

Contact lenses made of polysiloxanes are flexible, have good optical properties, are chemically and biologically inert and show an excellent  Oxygen permeability. The pronounced hydrophobicity of this is disadvantageous Materials. The hydrophobic character and mobility of the polysiloxane chains cause a quick and strong interaction with ingredients of the Tear fluid. Untreated hydrophobic polysiloxane lenses are therefore quickly especially of lipids from the tear, shows what they become cloudy and opaque leaves. In addition, dehydration occurs, which leads to very firm adhesion of the Lens on the cornea of the eye. This phenomenon is under that The term suction cup effect is known. It in turn leads to eye irritation to damage to the cornea and thus worse Comfort or even uselessness or incompatibility of the lens. Therefore Such contact lenses must be treated in the eye before application, so that permanent wetting with the tear fluid is guaranteed.

To avoid these disadvantages, various methods are available to improve the hydrophilic properties of polysiloxane lenses have been developed.

For example, Robert et al. in EP 0 643 083 a method for forming a hydrophilic IPN (interpenetrating network) on a contact lens, one Silicon lens in a solution of acrylic acid, an unsaturated crosslinker and a photoinitiator in a suitable solvent such as. B. swelled hexane and is polymerized by means of UV radiation.

Furthermore, Merril et al. in U.S. 3,916,033 and U.S. 4,099,859 Process described in which by means of high-energy ionizing radiation a hydrophilic coating on silicone elastomer contact lenses by grafting be applied.

A disadvantage of these methods is, in addition to the expenditure on equipment, that Contact lenses undergo discoloration and deformation due to the radiation can.

Furthermore, it has been proposed to be hydrophilic by treatment in gas plasma To spray monomers onto the lens surface. Such a process that too  under the term plasma grafting, Chen et al. in U.S. 4,143,949 have been described. In addition to the cost-intensive high expenditure on equipment, the It is difficult to control the coating thickness. In addition, not implemented Monomers in the coating to irritate the eye. The durability too such coatings are not always given.

Methods for hydrophilizing contact lenses have also been developed at which a hydrophilizing agent only adsorptively on or in the Contact lens material is brought. For example, EP 0 713 106 describes a method for Hydrophilization of contact lenses, with the side facing away from the eye a hydrophilic polysilicon oil, a polysaccharide or denatured collagen is coated. A disadvantage of such coatings is that the resistance in Solution is limited. Especially with a mechanical lens cleaning with the Fingers quickly lose the surface's hydrophilicity.

EP 0 599 150 teaches a method in which a substrate is first treated with chlorosilanes is treated. The chlorosilanes are adsorbed and subsequently hydrolyzed. On this layer can be another layer, e.g. B. saccharins, polyethers or Polyvinylamines are chemically bound. The procedure is particularly based on Glass is used as a substrate because the chlorosilanes are attached to the Bind substrate.

If substrates without functional groups are coated, then the Coating an activation of the substrate z. B. performed with UV radiation become.

US 5 736 251 describes a method for improving the lubricity of Polymers described. The polymers are, optionally after a additional, activation, treated with crosslinkable silanes and then in Cured presence of water and optionally a catalyst. Thereby a thick cross-linked siloxane layer forms, which under certain conditions can also have island-shaped elevations. The lubricity of the like modified polymers is of the type and length of the substituents of the silane  dependent, whereby substituents with more than 10 C atoms are less effective than short chain substituents. In addition, coated polymers do not show any Hydrophilization of the surface.

The object of the present invention was therefore to provide a method for permanent To provide hydrophilic coating of polymers that is easy to perform and supplies coatings that are also suitable for physiologically sensitive areas (e.g. Eyes) can be used.

Surprisingly, it was found that polymer substrates by successive Implement with functionalized silane derivatives and a hydrophilic or latent hydrophilic compound can be coated hydrophilic in a simple manner.

Are latently hydrophilic compounds for the purposes of the present invention Compounds that are only hydrophilic in character through a chemical reaction receive. Examples of such latently hydrophilic compounds are Carboxylic acid esters by saponification in the hydrophilic carboxylic acids can be converted. Another example of latently hydrophilic Compounds are epoxides, because of the reaction with the functionalized Silane derivative of the epoxy ring opened and a hydrophilic hydroxyl group as End group becomes free.

The present invention therefore relates to a process for the production of hydrophilic coatings on polymeric substrates, the polymeric substrates first being treated with a silane derivative of the formula (I)

[Y (R ¹ Z) _m R ² ] _n SiR ³ _o X _4-no (I)

With
o = 0 to 2,
n = 0 to (3-o),
m = 0 to 5
R ¹ , R ² , R ³ = C ₁ -C ₁₂ -alkyl radical, C ₂ -C ₁₂ -alkylene radical, phenyl radical or phenylalkyl radical, where R ² and R ^{3 are} each identical or different to R ¹ ,

and then with a hydrophilic or latently hydrophilic compound be implemented, the surface of the polymeric substrate after the Implementation with the silane derivative has a structure.

Are latently hydrophilic compounds for the purposes of the present invention Compounds that have little or no hydrophilic properties and by the coating reaction according to the invention or a subsequent reaction Preserve hydrophilic character. An example of latently hydrophilic compounds are Epoxies.

The following silane derivatives are particularly suitable for carrying out the process according to the invention:

The present invention furthermore relates to the use of polymeric substrates which have been coated in accordance with claims 1 to 6 Manufacture of articles for use in the fields of food and Luxury equipment technology, water technology, biotechnology, hygiene provision and especially medical technology.

In addition, products that are wholly or partly according to claims 1 to 6 were coated and in the fields of food and beverage technology, Water technology, biotechnology, hygiene prevention and especially the.

Medical technology are used, object of the present invention. The method according to the invention offers decisive advantages over the conventional methods:
The silane derivatives used do not form a continuous film on the substrate surface, but rather isolated drops. These drops can have a diameter of approximately 0.1-30 µm, have a narrow distribution and are firmly, partly covalently, connected to the substrate surface. The average drop diameter can be adjusted by varying the coating parameters. The functional groups (Y in formula I) of the silane derivative used are located on the surface of the drops and are accessible there for further chemical conversion. If these groups are then reacted with a monomeric or polymeric hydrophilic or latently hydrophilic compound, this compound is chemically or physically bound to the substrate via the silane derivative.

The formation of the drops causes a microstructuring of the substrate surface and associated with a macroscopic superficial hydrophilization. It but remain enough untreated areas on the surface, so that the physiological or mechanical properties of the polymer substrate are not be changed significantly.  

The silane derivative is preferably used on the substrate surface in Solution. The solvent can also act as an additional swelling agent. Solutions in the range of 0.1-5.0 vol% silane derivative, preferably in hexane Solvents have proven themselves in practice. But also others, the substrate swelling solvents such as. B. tetrahydrofuran, cyclohexane or toluene are in The inventive method can be used.

The substrate to be treated is immersed in such a solution of the silane derivative approx. 1 s to 10 min or until the substrate swells completely, preferably 1-150 s at room temperature and then dries.

No specific temperature has to be maintained during the drying process become; Room temperature (20-25 ° C) is sufficient in most cases. However, thermostatting is advantageous depending on the vapor pressure of the Solvent in the range of 0 to 40 ° C during drying. The Drying process can be carried out under protective gas or in air, a dust-free atmosphere is recommended.

In certain cases where only desired areas are to be treated, the immersion can also take place partially. As an alternative to immersion, the The silane derivative can also be applied by spraying or brushing on.

However, the silane derivative can also be solvent-free from the gas phase on the Substrate surface to be deposited. Here are possibly longer reaction or Adherence to swelling times, the drying step can be omitted here.

After reacting the polymeric substrate with the silane derivative according to formula I can the drop layer thus obtained is hydrolyzed. This hydrolysis can take place during or after drying. The hydrolysis is expediently carried out during of drying in air, since the water content in the air is usually extensive Hydrolysis enables. Another option is to look after Drying a gentle steam treatment of the coated subrate perform. The hydrolysis should be as complete as possible. There too  extremely hydrophobic polymeric substrates by means of the inventive Process can also be coated with an incomplete one Expect hydrolysis. Hydrolysis times in air of 4 hours have changed in the Proven in practice. With a steam treatment is about 2 hours Treatment time. The hydrolysis of the coated substrates can followed by drying at 40-150 ° C, preferably at 70-130 ° C.

After the reaction of the polymeric substrate with the silane derivative, the hydrolysis and possibly final drying at an elevated temperature Treatment with the hydrophilic or latently hydrophilic compound.

In the process according to the invention, all can be hydrophilic or latently hydrophilic Compounds are used, which after treatment with the silane derivative enter ionic, adsorptive and or covalent bond and directly or after a additional chemical conversion, adequate wetting with water guarantee. In the case of epoxides, especially ethylene oxide, the Ring opening of the epoxide polymerizes the epoxide onto the functional one Group Y of the silane derivative initiated. The result is a polyether chain with a Hydroxyl group as end group.

Among others, they have proven themselves to be hydrohilic or latently hydrophilic compounds Ethylene oxide, propylene oxide, polyethylene oxide, polypropylene oxide, polyacrylic acid, Polyacrylic acid esters, polyvinyl alcohol, polyvinylamines, polymethacrylic acid esters, Polymethacrylic acid, polyether, polyvinyl lactams, polymethacrylamines, saccharides, Polyacrylamides, polymethacrylamides, maleic anhydride copolymers or Mixtures of these compounds.

Treatment with polymeric or monomeric compounds as hydrophilic or latent hydrophilic compound is a reaction with acid chlorides, inorganic or equate with organic acids. When treated with acids form corresponding ionic compounds. When implementing z. B. one The amino function of the silane derivative with acetic acid forms the corresponding one Ammonium acetate the hydrophilic surface.  

The hydrophilic or latently hydrophilic compounds are conveniently in Solution, e.g. B. applied from an aqueous or alcoholic solution. The Treatment times are 1 to 60 minutes. the temperatures are between 20 and 90 ° C.

The reactions of the polymeric substrate with the silane derivative according to formula I. and the hydrophilic or latently hydrophilic compounds can dry out at 20 to 150 ° C, preferably at 50 to 130 ° C, particularly preferably at 80 to Connect 120 ° C. In some cases, this drying can result in hydrolysis or other chemical reaction, e.g. B. saponification to improve the Connect hydrophilic properties.

During the implementation of the hydrophilic or latently hydrophilic compound with the already coated substrate or also during the subsequent drying this compound is linked to the polymer via the silane derivative Substrate. This can be done chemically or purely physically. In case of Treatment of e.g. B. amino groups of the silane derivative with carboxylic anhydrides or carboxylic acids are not only ionic but also chemical assume amide functions.

By means of the method according to the invention, all polymeric substrates can coated, which are compatible with the silane derivative or its solution. In the process according to the invention, the polymer substrate in particular can be Polysiloxanes such as polydimethylsiloxane, polyurethanes, polyamides, polyesters, Polyethylene, polypropylene, polystyrene, polyvinyl chloride, synthetic and Natural rubber, polycarbonates or polymethyl methacrylate can be used. The Substrates can be coated as granules, semi-finished or finished products. in the The case of the granulate or semi-finished product is in the further processing on mechanical properties of the coating. Become finished products coated like contact lenses, can be dipped, sprayed, Brushing or steaming selected parts of the product can be coated.  

As products wholly or partly using the method according to the invention coated, come z. B. textiles, furniture and appliances, pipes and Hoses, plastic-coated cables, floors, wall and ceiling surfaces, Storage containers, packaging, window frames, telephone receivers, toilet seats, Door handles, handles and seat belts in public transport and medical articles in question.

Medical articles are e.g. B. drainage, guidewires, cannulas, Intraocular lenses, stents, vascular prostheses, joint prostheses, bone replacements materials, ligament prostheses, dentures, blood bags, sutures, bandages fabrics, fleece products, surgical instruments, skin implants, breast implants, medical African tubes catheters or contact lenses.

The following examples are intended to explain the present invention in more detail, without however, limit their scope.

Examples Preparation of the coating solution version 1

In air, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane becomes at room temperature mixed in various concentrations with anhydrous n-hexane. The so prepared solution can only be used for a short time, because after about 30 minutes Humidity, hydrolysis and crosslinking of the silane occurs, which is reflected in the Appearance of a cloudiness.

Variant 2

Under an argon protective gas atmosphere, N- (2-aminoethyl) -3- aminopropyltrimethoxysilane in various concentrations with anhydrous mixed n-hexane. The solution thus prepared is for a long time usable.  

Variant 3

Under an argon protective gas atmosphere, N- (2-aminoethyl) -3- aminopropyltrimethoxysilane in various concentrations with anhydrous Cyclohexane mixed. The solution thus prepared is for a long time usable.

Variant 4

Under an argon protective gas atmosphere, 3- Aminopropyltriethoxysilane in various concentrations with anhydrous mixed n-hexane. The solution thus prepared is for a long time usable.

Variant 5

Under an argon protective gas atmosphere, 3-trimethoxy silylpropyl-diethylenetriamine in various concentrations with anhydrous mixed n-hexane. The solution thus prepared is for a long time usable.

example 1 Coating of polysiloxane films

Perthese® polysiloxane films (Laboratoire Perouse Implant, France) cleaned thoroughly with water and isopropanol and at room temperature dried. The foils pretreated in this way are placed in the same way as in 2) 1.0 vol% coating solution described immersed. It will be at Room temperature in air to constant weight, then at 110 ° C for 1 h dried.

After the first coating, the film is immersed in a 2.5% solution of polyacrylic acid (M _W ≈ 2000) in pure ethanol for 20 min, dried at room temperature and then dried again at 110 ° C. for 1 h. The coated films are extracted in water for about 4 hours at room temperature. The finished coated films are completely wetted by water (contact angle 0 °) and the optical transparency of the films is not influenced by the coating in the hydrated state.

Example 2 Coating of polysiloxane contact lenses

Polysiloxane contact lenses made from the material according to EP 0 374 659 are cleaned thoroughly with water and isopropanol and at room temperature dried. The lenses pretreated in this way are placed in the same way as in 2) 1.0 vol% coating solution described immersed. It will be at Room temperature in air to constant weight, then at 110 ° C for 1 h dried.

After the first coating, the contact lenses are immersed in a 2.5% solution of polyacrylic acid (M _W ≈ 2000) in pure ethanol for 20 min, dried at room temperature and then dried again at 110 ° C. for 1 h. The coated lenses are extracted in sterile water for about 4 hours at room temperature. The fully coated contact lenses are completely wetted by water (contact angle 0 °) and the optical transparency of the contact lenses is not affected by the coating in the hydrated state. The contact lenses are stored in sterile phosphate buffered physiological saline.

6) Abrasion test on coated polysiloxane contact lenses

A polysiloxane contact lens coated in accordance with Example 2 is used several times with a conventional contact lens cleaner between the fingertips cleaned. The treatment showed no change in the lens Wetting properties. The coating is despite mechanical stress stable against delamination.

7) Storage stability of coated polysiloxane contact lenses

A polysiloxane contact lens coated according to Example 2 is over several months in sterile phosphate buffered physiological Saline solution stored. The lens showed no delamination of the  Coating, still changed the optical properties or that Wetting behavior.

Example 3 Coating of polyethylene films

Polyethylene films are cleaned thoroughly with water and with isopropanol and at Room temperature dried. The films pretreated in this way are put into a 20 sec immersed 1.0 vol% coating solution described under 2). It is at room temperature in air to constant weight, then for 1 h dried at 100 ° C.

After the first coating, the film is immersed in a 2.5% solution of polyacrylic acid (M _W ≈ 2000) in pure ethanol for 20 min, dried at room temperature and then dried again at 100 ° C. for 1 h. The coated films are extracted in water for about 4 hours at room temperature. The finished coated films are completely wetted with water (contact angle 0 °).

Example 4 Variation of drop diameter

Perthese® polysiloxane films (Laboratoire Perouse Implant, France) cleaned thoroughly with water and isopropanol and at room temperature dried. Films pretreated in this way are individually 10 s in a as in 2) described 5.0, 2.0, 1.25, 1.0 and 0.5 vol% coating solution submerged. It is at room temperature in air to constant weight, then dried at 110 ° C for 1 h.

Films coated in this way were scanned with a scanning electron microscope (Phillips, SEM 515) examined. The samples were taken before taking Sputtered with money / palladium, the magnification was 500: 1 each.

Fig. 1-5 document the dependence of the drop size and thus the elevations on the silane concentration.

Table 1:

Example 5 Coating of polysiloxane contact lenses

Polysiloxane contact lenses made from the material according to EP 0 374 659 are cleaned thoroughly with water and isopropanol and at room temperature dried. The lenses pretreated in this way are placed in the same way as in 4) 1.0 vol% coating solution described immersed. It will be at constant 15 ° C in air to constant weight, then for 1 h at 110 ° C dried.

After the first coating, the contact lenses are immersed in a 2.5% solution of polyacrylic acid (M _W ≈ 2000) in pure ethanol for 20 min, dried at room temperature and then dried again at 110 ° C. for 1 h. The coated lenses are extracted in sterile water for about 4 hours at room temperature. The fully coated contact lenses are completely wetted by water (contact angle 0 °) and the optical transparency of the contact lenses is not affected by the coating in the hydrated state. The contact lenses are stored in sterile phosphate buffered physiological saline.

Example 6 Coating of polysiloxane contact lenses

Polysiloxane contact lenses made from the material according to EP 0 374 659 are cleaned thoroughly with water and isopropanol and at room temperature dried. The lenses pretreated in this way are placed in a 150 s as under 2)  described 5.0 vol% coating solution described immersed. It will be at constant 15 ° C in air to constant weight, then for 1 h at 110 ° C dried.

After the first coating, the contact lenses are immersed in a 1.5% solution of polyacrylic acid (M _W ≈ 2000) in pure ethanol for 20 min, dried at room temperature and then dried again at 110 ° C. for 1 h. The coated lenses are extracted in sterile water for about 4 hours at room temperature. The fully coated contact lenses are completely wetted by water (contact angle 0 °) and the optical transparency of the contact lenses is not affected by the coating in the hydrated state. The contact lenses are stored in sterile phosphate-buffered physiological saline.

Example 7 Coating of polysiloxane contact lenses

Polysiloxane contact lenses made from the material according to EP 0 374 659 are cleaned thoroughly with water and isopropanol and at room temperature dried. The lenses pretreated in this way are placed in the same way as in 5) 1.0 vol% coating solution described immersed. It will be at constant 15 ° C in air to constant weight, then for 1 h at 110 ° C dried.

After the first coating, the contact lenses are immersed in a 1.5% solution of polyacrylic acid (M _W ≈ 2000) in pure ethanol for 20 min, dried at room temperature and then dried again at 110 ° C. for 1 h. The coated lenses are extracted in sterile water for about 4 hours at room temperature. The fully coated contact lenses are completely wetted by water (contact angle 0 °) and the optical transparency of the contact lenses is not affected by the coating in the hydrated state. The contact lenses are stored in sterile phosphate buffered physiological saline.

Claims (10)

1. A process for the preparation of hydrophilic coatings on polymeric substrates, characterized in that the polymeric substrates first with a silane derivative of the formula I.
[Y (R ¹ Z) _m R ² ] _n SiR ³ _o X _4-no (I)
With
o = 0 to 2,
n = 0 to (3-o),
m = 0 to 5
R ¹ , R ² , R ³ = C ₁ -C ₁₂ -alkyl radical, C ₂ -C ₁₂ -alkylene radical, phenyl radical or phenylalkyl radical, where R ² and R ^{3 are} each identical or different to R ¹ ,
and then reacted with a hydrophilic or latently hydrophilic compound, the surface of the polymeric substrate having a structure after the reaction with the silane derivative. 2. The method according to claim 1, characterized, that as the hydrophilic or latently hydrophilic compound, ethylene oxide, Propylene oxide, polyethylene oxide, polypropylene oxide, polyacrylic acid, Polyacrylic acid esters, polymethacrylic acid, polymethacrylic acid esters, Polyvinyl alcohol, polyvinyl amines, polyethers, polyvinyl lactams, Polymethacrylamines, saccharides, polyacrylamides, polymethacrylamides, Maleic anhydride copolymers of the mixtures of these compounds be used. 3. The method according to claim 1, characterized, that as a hydrophilic or latently hydrophilic compound, acid chlorides, inorganic acids or organic acids can be used. 4. The method according to any one of claims 1 to 3, characterized, that after reacting the polymeric substrate with the silane derivative according to the formula I the structured surface thus obtained is hydrolyzed. 5. The method according to any one of claims 1 to 4, characterized, that after reacting the polymeric substrate with the silar derivative according to the formula I and a hydrophilic or latently hydrophilic compound during drying 20-150 ° C is carried out. 6. The method according to any one of claims 1 to 5, characterized, that as the polymeric substrate polysiloxane, polydimethylsiloxane, polyethylene, Polyamides, polyurethanes, polyester, polypropylene, polystyrene, polyvinyl chloride, Synthetic and natural rubber, polycarbonates or polymethyl methacrylate be used.   7. Use of polymeric substrates according to claims 1 to 6 coated for the manufacture of articles for use on the fields of food and beverage technology, water technology, Biotechnology, hygiene prevention and medical technology. 8. Products entirely or partially coated according to claims 1 to 6 have been used in the fields of food and Luxury equipment technology, water technology, biotechnology, hygiene provision and Medical technology. 9. Products according to claim 8, characterized, that the products are textiles, furniture and appliances, pipes and hoses, plastic-coated cables, floors, wall and ceiling surfaces, Storage containers, packaging, window frames, telephone receivers, toilet seats, Door handles, handles and seat belts in public transport and medical articles are. 10. Products according to claim 9, characterized, that the medical articles drainage, guidewires, cannulas, Intraocular lenses, stents, vascular prostheses, joint prostheses, bone replacements materials, band prostheses, dentures, blood bags, sutures, Bandages, fleece products, surgical instruments, skin implants, breasts implants, medical tubes, catheters or contact lenses.