KR100976713B1 - Self-cleaning synthetic body and method for producing the same - Google Patents

Abstract

The present invention provides a coating comprising siloxane coating (a) on a synthetic substrate and curing, increasing the surface energy of the polar fraction of the cured siloxane coating on the substrate to a value of at least 10 mN / m and comprising photocatalytically active TiO ₂ particles ( A self-cleaning composite obtained by applying and curing b) to a synthetic substrate.

Midnight, Plastic Products, Siloxanes, Surface Energy, Polar Components, Photocatalysts, TiO2

Description

Self-cleaning synthetic body and method for producing the same             

The present invention relates to a self-cleaning plastic product having a TiO ₂ particle containing siloxane coating.

Midnight products become super-hydrophilic through irradiation with UV light in the presence of water and can break down organic contaminants to provide carbon dioxide and water. This surface property is generally achieved through the photocatalytic action of titanium dioxide, which can be fixed to a solid support, for example, firmly bonded to the substrate by stoving at high temperatures. One example is silicate glass for midnight windows, as described in Rhodia Chemie, EP 850 203 B1.

Plastic substrates, such as acrylic sheets or polycarbonates, widely used as windowpane materials or transparent soundproof walls, are intended to have maximum transparency and cleanliness for aesthetic reasons, in order to allow rail passengers or motorists to see the surrounding landscape clearly. do. They are especially used in bridges, but they are also used to alleviate the monotony of concrete soundproof walls, and contribute to reducing the fatigue of motorists.

Automobile exhaust, worn tire materials, dust and organic contaminants cause a sharp deterioration of the attractive and aesthetic properties of transparent sound barriers. Thus, numerous attempts have been made to provide a self-cleaning coating to a transparent plastic. The object of the present application is to use the photocatalytic activity of titanium dioxide to decompose contaminants attached to the surface of the substrate, while the organic substrate itself is protected from degradation by titanium dioxide.

Plastic products provided with a midnight siloxane coating are likewise known. These substrates generally have a double layer of siloxanes having different compositions, and only the outer layer contains a photocatalyst additive such as TiO _{2 in the} form of anatase or brookite.

For example, EP 1 022 318 describes a coated sheet of plastic having a photocatalyst layer. However, the examples only provide sheets or films with a total of 1.2 μm thin films, which only have very low scratch resistance.

While it is described in the specification that it is also possible to obtain a thicker layer, the only technique is that a thicker layer can be obtained through repeated coating of the siloxane coating composition. However, the TiO ₂ -containing siloxane layer, if no additives are used, has poor adhesion to the initially applied siloxane layer which serves as the primer for protecting the underlying plastic product.

In order to solve the problem of insufficient adhesion of the substrate, an inorganic-organic layer made of siloxane network may be used as the separating layer of the plastic substrate. When provided with a suitable composition, the layer is significantly superior in adhesion to pure inorganic materials, and due to its hybrid properties, the titanium dioxide becomes more resistant to photocatalytic activity than pure organic layers.

However, it has been found in the experiment that, due to weather resistance, in particular UV irradiation, the scratch resistance of a plastic article provided with an inorganic-organic layer decreases over time, at which time the transparency of the plastic article decreases. In addition, scratch resistance immediately after production is also unsatisfactory.

Thus, a problem with these plastic articles of the prior art is their low scratch resistance or low weather resistance. As a result, due to environmental influences, the coatings peel off over time, and their self-cleaning ability is lost.

Thus, in view of the prior art mentioned and discussed herein, it was an object of the present invention to provide a self-cleaning plastic product having a particularly high scratch resistance.

Another object of the present invention is a plastic product having high durability, in particular high weather resistance or resistance to UV radiation.

Another object based on the present invention was to provide a scratch resistant self-cleaning plastic product which can be produced particularly simply. For example, substrates that can be used to make plastic products can be those obtainable, in particular, through extrusion or injection molding, or through casting processes.

It was furthermore an object of the present invention to provide a plastic product which can be manufactured at low cost.

It is yet another object of the present invention to provide a scratch resistant self-cleaning plastic product having excellent mechanical properties. This property is particularly important for applications where plastic products have high impact resistance.

In addition, plastic products should have particularly good optical properties.

Another object of the present invention is to provide a plastic product in which the size and shape can be easily adapted to the requirements.

The plastic product described in claim 1 achieves these objects and, although not specifically mentioned, achieves other objects which are obvious or essential consequences of the situations discussed herein. Useful modifications of the plastic article of the invention can be protected by the dependent claims of claim 1.

Claim 22 achieves the basic objectives with respect to the manufacturing process.

In particular, self-cleaning plastic products having high scratch resistance prepare a plastic substrate, apply and cure the siloxane coating (a), increase the polar component of the surface energy of the cured siloxane coating to a value of 10 mN / m or more, and photocatalyst The coating (b) comprising TiO ₂ particles is applied and cured, which is obtained successfully.

In particular, certain advantages achieved by the measurement of the present invention are as follows.

The plastic article of the invention has a high resistance to surface scratches.

The plastic article of the invention has a high resistance to UV radiation.             

Plastic products also exhibit high levels of midnight, especially at very low UV irradiation levels.

In addition, the plastic products of the invention can be produced at a particularly low cost without the need for expensive additives.

The present invention also allows the production of a self-cleaning coating on a plastic substrate already coated with siloxane. This particular advantage is that it is possible to obtain sheets from the manufacture of a plastic product provided with a scratch resistant coating and then to provide these sheets with another coating having self-cleaning properties.

The scratch resistant plastic articles of the invention can be adapted to specific requirements. In particular, the size and shape of a plastic product can vary widely without the damage created as a result of its scratch resistance or self-cleaning properties. Moreover, the present invention also provides a plastic article having excellent optical properties.

The scratch resistant plastic article of the invention has excellent mechanical properties.

The plastic article of the invention is obtainable through the coating of a plastic substrate. Plastic substrates suitable for the purposes of the present invention are known per se. These substrates include in particular polycarbonates, polystyrenes, polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), cycloolefin polymers (COC) and / or poly (meth) acrylates. do. Preferred herein are polycarbonates, cycloolefin polymers and poly (meth) acrylates, with poly (meth) acrylates being particularly preferred.             

Polycarbonates are known to those skilled in the art. Polycarbonates can be considered as polyesters which consist of carbonic acid and aliphatic or aromatic dihydroxy compounds in form. These can be easily obtained by reacting diglycol or bisphenol with phosgene or carbon diester in a polycondensation or transesterification reaction.

Preference is given here to polycarbonates derived from bisphenols. Specific bisphenols of these are 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis- (4-hydroxyphenyl) butane (bisphenol B), 1,1-bis- (4 -Hydroxyphenyl) cyclohexane (bisphenol C), 2,2-methylenediphenol (bisphenol F), 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane (tetrabromobisphenol A) and 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (tetramethylbisphenol A).

These aromatic polycarbonates are generally prepared by interfacial polycondensation or transesterification. Encycl. Polym. Sci. Engng. 11, 648-718.

In interfacial polycondensation, bisphenols in the form of alkaline aqueous solutions are emulsified in an inert organic solvent such as methylene chloride, chlorobenzene or tetrahydrofuran and react with phosgene in a reaction comprising the steps. Amines are used as catalysts and phase transfer catalysts are used in the case of sterically hindered bisphenols. The resulting polymer is soluble in the organic solvent used.

The nature of the polymer can vary widely through the choice of bisphenols. When different bisphenols are used together, block polymers may also be constructed in multistage polycondensation.

Cycloolefin polymers can be obtained using cyclic olefins, in particular using polycyclic olefins.

Cyclic olefins are, for example, monocyclic olefins such as cyclopentene, cyclopentadiene, cyclohexene, cycloheptene, cyclooctene, and also alkyl derivatives of these monocyclic olefins having 1 to 3 carbon atoms, For example, methyl, ethyl or propyl such as methylcyclohexene or dimethylcyclohexene and also acrylates and / or methacrylate derivatives of these monocyclic compounds. Moreover, cycloalkanes having olefinic side chains may also be used as cyclic olefins, for example cyclopentyl methacrylate.

Crosslinked polycyclic olefin compounds are preferred. These polycyclic olefin compounds may have double bonds in the ring or in the side chain when they are crosslinked polycyclic cycloalkenes. In this case, they are vinyl derivatives, allyloxycarboxy derivatives or (meth) acryloxy derivatives of the polycyclic cycloalkane compounds. These compounds may also be alkyl, aryl or aralkyl substituents.

Without any intended limitation, examples of polycyclic compounds include bicyclo [2.2.1] hept-2-ene (norbornene), bicyclo [2.2.1] hept-2,5-diene (2,5- Norbornadiene), ethylbicyclo [2.2.1] hept-2-ene (ethylnorbornene), ethylidenebicyclo [2.2.1] hept-2-ene (ethylidene-2-norbornene), phenyl Bicyclo [2.2.1] hept-2-ene, bicyclo [4.3.0] nona-3,8-diene, tricyclo [4.3.0.1 ^2,5 ] -3-decene, tricyclo [4.3.0.1 ^{2 , 5} ] -3,8-decene- (3,8-dihydrodicyclopentadiene), tricyclo [4.4.0.1 ^2,5 ] -3-undecene, tetracyclo [4.4.0.1 ^2,5 , 1 ^7,10 ] -3-dodecene, ethylidene tetracyclo [4.4.0.1 ^2,5 , 1 ^7,10 ] -3-dodecene, methyloxycarbonyl-tetracyclo [4.4.0.1 ^2,5 , 1 ^{7 , 10} ] -3-dodecene, ethylidene-9-ethyltetracyclo [4.4.0.1 ^2,5 , 1 ^7,10 ] 3-dodecene, pentacyclo [4.7.0.1 ^2,5 , 0, 0 ^{3, 13,} 1 ^9,12] -3-penta-decene, penta-bicyclo [6.1.1 ^3,6 0 ^2,7 .0 ^9,13] -4 Other decene, hexafluoro bicyclo ^{[6.6.1.1 3,6 .1 10,13 .0 2,7 .0} 9,14] -4- hepta-decene, hexadecyl dimethyl bicyclo [6.6.1.1 ^3,6 .1 ^10,13. 0 ^2,7 .0 ^9,14 ] -4-heptadecene, bis (allyloxycarboxy) tricyclo [4.3.0.1 ^2,5 ] decane, bis (methacryloxy) tricyclo [4.3.0.1 ^2,5 ] Decane, bis (acryloxy) tricyclo [4.3.0.1 ^2,5 ] decane.

Cycloolefin polymers are prepared using one or more cycloolefin compounds described above, in particular polycyclic hydrocarbon compounds. Moreover, the preparation of cycloolefin polymers may employ other olefins that may be copolymerized with the cycloolefin monomers described above. Examples thereof include ethylene, propylene, isoprene, butadiene, methylpentene, styrene and vinyltoluene.

Most of the olefins mentioned above, in particular cycloolefins and polycycloolefins, may be commercially available. In addition, many cyclic and polycyclic olefins can be obtained by Diels-Alder addition.

Cycloolefin polymers are, in particular, Japanese Patent Publication No. 1118/1972, Japanese Patent Publication No. 43412/1983, Japanese Patent Publication No. 1442/1986, Japanese Patent Publication No. 1991/1987, and Japanese Patent Application No. 75700/1975. Japanese Patent Application No. 129434/1980, Japanese Patent Application No. 127728/1983, Japanese Patent Application No. 168708/1985, Japanese Patent Application No. 271308/1986, Japanese Patent Application No. 221118/1988, Japanese Patent Application No. 180976/1990, European Patent Publication No. 0 6 610 851, European Patent Publication No. 0 6 485 893, European Patent Publication No. 0 6 407 870 and European Patent Publication No. 0 6 688 801 As one can, it may be prepared in a known manner.

Cycloolefin polymers can be polymerized using, for example, aluminum compounds, vanadium compounds, tungsten compounds or boron compounds as catalysts in a solvent.

Depending on the state, in particular the catalyst used, it is assumed that the polymerization can proceed with ring opening or ring opening.

It is also possible to obtain cycloolefin polymers by free radical polymerization using initiators or light as free radical generators. This applies in particular to acryloyl derivatives of cycloolefins and / or cycloalkanes. This type of polymerization can occur in solution or in bulk.

Another preferred plastic substrate includes poly (meth) acrylates. These polymers are generally obtained by free-radical polymerization of mixtures comprising (meth) acrylates. The term (meth) acrylate includes methacrylate and acrylate and mixtures of both.

These monomers are well known. Among them, in particular, (meth) acrylates derived from saturated alcohols such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, 3 Tert-butyl (meth) acrylate, pentyl (meth) acrylate and 2-ethylhexyl (meth) acrylate; (Meth) acrylates derived from unsaturated alcohols such as oleyl (meth) acrylate, 2-propynyl (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate; Allyl (meth) acrylates such as benzyl (meth) acrylate or phenyl (meth) acrylate (each aryl radical may be unsubstituted or substituted with up to 4 substituents); Cycloalkyl (meth) acrylates such as 3-vinylcyclohexyl (meth) acrylate, bornyl (meth) acrylate; Hydroxyalkyl (meth) acrylates such as 3-hydroxypropyl (meth) acrylate, 3,4-dihydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2 -Hydroxypropyl (meth) acrylate; Glycol di (meth) acrylates such as 1,4-butanediol di (meth) acrylate; (Meth) acrylates of other alcohols such as tetrahydrofurfuryl (meth) acrylate, vinyloxyethoxyethyl (meth) acrylate; Amides and nitriles of (meth) acrylic acid, for example N- (3-dimethylaminopropyl) (meth) acrylamide, N- (diethylphosphono) (meth) acrylamide, 1-methacryloyl amido -2-methyl-2-propanol; Sulfur-containing methacrylates such as ethylsulfinylethyl (meth) acrylate, 4-thiocyanatobutyl (meth) acrylate, ethylsulfonylethyl (meth) acrylate, thiocyanatomethyl (meth ) Acrylate, methylsulfinylmethyl (meth) acrylate, bis ((meth) acryloyloxyethyl) sulfide; Polyfunctional (meth) acrylates such as trimethylloylpropane tri (meth) acrylate, pentaerythritol terra (meth) acrylate and pentaerythritol tri (meth) acrylate.

In one preferred embodiment of the invention these mixtures comprise at least 40% by weight, preferably at least 60% by weight and particularly preferably at least 80% by weight of methyl methacrylate, based on the weight of the monomers.

In addition to the (meth) acrylates mentioned above, the composition to be polymerized may also comprise methyl methacrylate and other unsaturated monomers copolymerizable with the aforementioned (meth) acrylates.

These examples include 1-alkenes such as 1-hexene, 1-heptene; Branched alkenes such as vinylcyclohexane, 3,3-dimethyl-1-propene, 3-methyl-1-diisobutylene, 4-methyl-1-pentene; Acrylonitrile; Vinyl esters such as vinyl acetate; Styrene, substituted styrene with one alkyl substituent in the side chain, for example α-methylstyrene and α-ethylstyrene, substituted styrene with one alkyl substituent on the ring, for example vinyltoluene and p-methyl Styrene, halogenated styrenes such as monochlorostyrene, dichlorostyrene, tribromostyrene and tetrabromostyrene; Heterocyclic vinyl compounds such as 2-vinylpyridine, 3-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinyl Pyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylpyrrolidone , 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidin, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxolane, vinylfuran, vinylthiophene, vinylthiolane, vinyl Thiazoles and hydrogenated vinylthiazoles, vinyloxazoles and hydrogenated vinyloxazoles; Vinyl and isoprenyl ethers; Maleic acid derivatives such as maleic anhydride, methylmaleic anhydride, maleimide, methylmaleimide; And dienes such as divinylbenzene.

The amount of these comonomers generally used is 0 to 60% by weight, preferably 0 to 40% by weight, particularly preferably 0 to 20% by weight, based on the weight of the monomers, wherein the compounds herein are Can be used or used as a mixture.

The polymerization is generally initiated by known free radical initiators. Examples of preferred initiators are azo initiators well known to those skilled in the art, such as AIBN and 1,1-azobiscyclo-hexanecarbonitrile, and also peroxy compounds such as methyl ethyl ketone Peroxite, acetylacetone peroxide, dilauryl peroxide, tert-butyl per-2-ethylhexanoate, ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, tertiary -Butyl peroxybenzoate, tert-butylperoxy isopropyl carbonate, 2,5-bis (2-ethylhexanoylperoxy) -2,5-dimethylhexane, tert-butylperoxy 2-ethylhexano Et, tert-butylperoxy 3,5,5-trimethylhexanoate, dicumyl peroxide, 1,1-bis (tert-butylperoxy) cyclohexane, 1,1-bis (tert-butyl Peroxy) -3,3,5-trimethylcyclohexane, cumyl hydroperoxide, tert-butyl hydro Oxides, bis (4-tert-butyl-cyclohexyl) peroxydicarbonate, mixtures of two or more of the aforementioned compounds, and also mixtures of the aforementioned compounds with compounds not mentioned which may also form free radicals .

Often used amounts of these compounds are from 0.01 to 10% by weight, preferably from 0.5 to 3% by weight, based on the weight of the monomers.

The polymers described above can be used individually or as mixtures. Here, for example, various polycarbonates, poly (meth) acrylates or cycloolefin polymers having different molecular weights or monomer compositions can also be used.

The plastic substrate of the present invention can be produced, for example, from the molding compositions of the polymers described above. To this end, generally thermoplastic molding processes, for example extrusion or injection molding, can be used.

The weight average molecular weight (M _w ) of the homopolymers and / or copolymers to be used according to the invention as molding compositions for producing plastic substrates can vary widely and the molar mass is generally used to process molding compositions. Conform to the application and method. However, without limitation, it is generally in the range of 20,000 to 1,000,000 g / mol, preferably 50,000 to 500,000 g / mol, particularly preferably 80,000 to 300,000 g / mol.

Plastic substrates can also be produced by cell casting processes. In these, by the examples, a suitable (meth) acrylic mixture is filled into the mold and polymerized. These (meth) acrylic mixtures generally comprise the above-mentioned (meth) acrylates, in particular methyl methacrylate. In addition, the (meth) acrylic mixtures comprise the copolymers mentioned above and may also comprise polymers, in particular poly (meth) acrylates, in particular for viscosity control.

The molding composition used to make the plastic substrate, and also the acrylic resin, may also include any type of conventional additives. Examples thereof include antistatic agents, antioxidants, mold release agents, flame retardants, lubricants, dyes, flow improvers, fillers, light stabilizers and organophosphorus compounds such as phosphites, phosphorinanes, phospholanes or phosphonates, Pigments, climate stabilizers and plasticizers. However, the amount of additives is limited in relation to the application.

)라는 상품명으로 시판중이다. 사이클로올레핀 중합체를 포함하는 바람직한 성형 조성물은 티코나(Ticona)로부터 토파스(

Topas)라는 상품명 및 니폰 제온(Nippon Zeon)으로부터 제오넥스(

Zeonex)라는 상품명으로 구입가능하다. 폴리카보네이트 성형 조성물은, 실시예에 의해, 바이엘(Bayer)로부터 마크롤론(

Makrolon)이라는 상품명 또는 제네럴 일렉트릭(General Electric)으로부터 렉산(

Lexan)이라는 상품명으로 수득가능하다.Particularly preferred molding compositions comprising poly (meth) acrylates are PLEXIGLAS from Degussa AG.

It is commercially available under the brand name). Preferred molding compositions comprising cycloolefin polymers are prepared from Topona (Ticona).

Topas) and Nippon Zeon from Xeonex (

Zeonex) is available under the trade name. Polycarbonate molding composition, according to the embodiment, from macro (Bayer)

From the trade name Makrolon or General Electric.

Lexan).

The plastic substrate particularly preferably comprises at least 80% by weight, in particular at least 90% by weight, of poly (meth) acrylate, polycarbonate and / or cycloolefin polymer, based on the total weight of the substrate. The plastic substrate is particularly preferably made of polymethyl methacrylate, which polymethyl methacrylate may comprise conventional additives.

In one preferred embodiment, the plastic substrate has an impact strength of at least 10 kJ / m 2, preferably at least 15 kJ / m 2 in accordance with ISO 179/1.

The shape and also the size of the plastic substrate is not critical to the invention. In general, often used substrates have a sheet or panel form and have a thickness of 1 to 200 mm, in particular 5 to 30 mm.

The plastic article of the present invention is first provided with a siloxane coating which protects the plastic substrate from photocatalytic degradation due to the photocatalytically acting coating layer.

Scratch resistant siloxane lacquers that can be used to produce the coating (a) are known per se and are used on polymeric varnishes. Their inorganic nature allows them to have good resistance to UV radiation and climate. By way of example, the preparation of these lacquers is described in EP 0 073911. Conventional lacquers are in particular those which comprise water and / or alcohol as solvent, in addition to siloxane condensation products.

These siloxane lacquers can be obtained in particular through condensation or hydrolysis of the organosilicon compounds of formula (I).

R ¹ _n SiX _4-n

In Formula I above,

R ¹ is a group having 1 to 20 carbon atoms,

X is an alkoxy radical or halogen having 1 to 20 carbon atoms,

n is an integer from 0 to 3,

The various radicals X or R ¹ may in each case be the same or different.

The expression "group of 1 to 20 carbon atoms" is characterized by radicals of organic compounds having 1 to 20 carbon atoms. It is a hetero group containing an alkyl group, a cycloalkyl group, an aromatic group, an alkenyl group and an alkynyl group having 1 to 20 carbon atoms, and also oxygen atoms, nitrogen atoms, sulfur atoms and phosphorus atoms, in addition to carbon atoms and hydrogen atoms, in particular Aliphatic and heteroaromatic groups. These groups mentioned may be branched or straight chain, wherein the radical R ¹ may be unsubstituted or substituted. Among the substituents, in particular, halogen, groups having 1 to 20 carbon atoms, nitro groups, sulfonic acid groups, alkoxy groups, cycloalkoxy groups, alkanoyl groups, alkoxycarbonyl groups, sulfone ester groups, sulfinic acid groups, sulfin ester groups, thiol groups , Cyanide groups, epoxy groups, (meth) acryloyl groups, amino groups and hydroxy groups. For the purposes of the present invention, the term "halogen" means fluorine atom, chlorine atom, bromine atom or iodine atom.

Among the preferred alkyl groups are methyl, ethyl, propyl, isopropyl, 1-butyl, 2-butyl, 2-methylpropyl, tert-butyl, pentyl, 2-methylbutyl, 1,1-dimethylpropyl, hexyl, heptyl, Octyl, 1,1,3,3-tetramethylbutyl, nonyl, 1-decyl, 2-decyl, undecyl, dodecyl, pentadecyl group and eicosyl group.

Examples of preferred cycloalkyl groups are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl group and cyclooctyl group, which are optionally substituted by branched or straight chain alkyl groups.

Among the preferred alkenyl groups are vinyl, allyl, 2-methyl-2-propene, 2-butenyl, 2-pentenyl, 2-decenyl group and 2-eicosenyl group.

Among the preferred alkynyl groups are ethynyl, propargyl, 2-methyl-2-propine, 2-butynyl, 2-pentynyl group and 2-decynyl group.

Among the preferred alkanoyl groups are formyl, acetyl, propionyl, 2-methylpropionyl, butyryl, valeroyl, pivaloyl, hexanoyl, decanoyl group and dodecanoyl group.

Among the preferred alkoxycarbonyl groups are methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, tert-butoxycarbonyl, hexyloxycarbonyl, 2-methylhexyloxycarbonyl, decyloxy Carbonyl groups or dodecyloxycarbonyl groups.

Among the preferred alkoxy groups are methoxy, ethoxy, propoxy, butoxy, tert-butoxy, hexyloxy, 2-methylhexyloxy, decyloxy group or dodecyloxy group.

Examples of preferred cycloalkoxy groups are cycloalkoxy groups wherein the hydrocarbon radical is one of the preferred cycloalkyl groups described above.

Among the preferred heteroaliphatic groups, at least one carbon unit is substituted by O, S or NR ⁸ groups, wherein R ⁸ is hydrogen or an alkyl group of 1 to 6 carbon atoms, or alkoxy or an aryl group of 1 to 6 carbon atoms. And preferred cycloalkyl radicals described above.

According to the invention, the aromatic groups are preferably radicals of mononuclear or polynuclear aromatic compounds having 6 to 14 carbon atoms, in particular 6 to 12 carbon atoms. Heteroaromatic groups are aryl radicals in which one or more CH groups are substituted by N and / or two or more adjacent CH groups are replaced by S, NH or O. According to the invention, preferred aromatic or heteroaromatic groups are benzene, naphthalene, biphenyl, diphenyl ether, diphenylmethane, diphenyldimethylmethane, bisphenone, diphenyl sulfone, thiophene, furan, pyrrole, thiazole , Oxazole, imidazole, isothiazole, isoxazole, pyrazole, 1,3,4-oxadiazole, 2,5-diphenyl-1,3,4-oxadiazole, 1,3,4 -Thiadiazole, 1,3,4-triazole, 2,5-diphenyl-1,3,4-triazole, 1,2,5-triphenyl-1,3,4-triazole, 1, 2,4-oxadiazole, 1,2,4-thiadiazole, 1,2,4-triazole, 1,2,3-triazole, 1,2,3,4-tetazole, benzo [b ] Thiophene, benzo [b] furan, indole, benzo [c] thiophene, benzo [c] furan, isoindole, benzoxazole, benzothiazole, benzimidazole, benzisoxazole, benzisothiazole, benzo Pyrazole, benzothiadiazole, benzotriazole, dibenzofuran, dibenzothiophene, carbazole, pyridine, pyrazine, pyrimidine, pyridazine, 1,3,5-triazine, 1,2,4-tri Ajin, 1,2,4,5-triazine, quinoline, isoquinoline, quinoxaline, quinazoline, cinnoline, 1,8-naphthyridine, 1,5-naphthyridine, 1,6-naphthyridine, 1,7- Derived from naphthyridine, phthalazine, pyridopyrimidine, purine, pteridine or 4H-quinolizine, diphenyl ether, anthracene and phenanthrene.

Preferred radicals R ¹ can be represented by formulas II, III or IV.

-(CH ₂ ) _m NH-[(CH ₂ ) _n -NH] _p H

In Formulas II to IV above,

m and n are 1 to 6,

p is 0 or 1,

q is 1 to 6,

R ₂ is methyl or hydrogen,

r is 1 to 6;

The radical R ¹ is very particularly preferably a methyl or ethyl group.

Concerning the definition of the group X of formula (I) for alkoxy groups having 1 to 20 carbon atoms and also halogen, reference may be made to the above definitions wherein the alkyl radicals of the alkoxy groups are preferably also of the formulas (II), It may be represented by Formula III or Formula IV. Group X is preferably a methoxy or ethoxy radical, or a bromine or chlorine atom.

For the preparation of siloxane lacquers, these compounds can be used individually or as mixtures.

Depending on the number of halogens or the number of alkoxy groups bonded to silicon via oxygen, the hydrolysis or condensation reactions form chained or branched siloxanes from the silane compounds of formula (I). In order to have three or more alkoxy groups or halogen atoms, it is preferred to use at least 60% by weight, in particular at least 80% by weight, based on the weight of the condensable silane.

Tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane and tetra-n-butoxysilane,

The trialkoxysilane is methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyl-trimethoxysilane, n-propyltriethoxysilane, isopropyltriethoxysilane, isopropyltrimeth Methoxysilane, isopropyltripropoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3 -Chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-amino Propyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxy Ethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercapto Propyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane , 3-glycidoxypropyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3- (meth ) Acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3-ureidopropyltrimethoxysilane and 3-ureidopropyltriethoxysilane,

The dialkoxysilane is dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldimethoxysilane , Diisopropyl diethoxysilane, di-n-butyldimethoxysilane, di-n-butyldiethoxysilane, di-n-pentyldimethoxysilane, di-n-pentyl diethoxysilane, di-n-hexyldimeth Methoxysilane, di-n-hexyl diethoxysilane, di-n-peptyldimethoxysilane, di-n-peptyldiethoxysilane, di-n-octyldimethoxysilane, di-n-octyldiethoxysilane, di- n-cyclohexyldimethoxysilane, di-n-cyclohexyldiethoxysilane, diphenyldimethoxysilane and diphenyldiethoxysilane.

Methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane and ethyltriethoxysilane are particularly preferred. In one particular embodiment of the invention, the proportion of these particularly preferred alkyltrialkoxysilanes is at least 80% by weight, in particular at least 90% by weight, based on the weight of the silane compound used.

In another aspect of the invention, it is also possible to use siloxane lacquers comprising colloidal dispersed SiO ₂ particles. These solutions can be obtained by the sol-gel method, in particular by the condensation of tetraalkoxysilanes and / or tetrahalosilanes.

Aqueous coating compositions generally comprise an amount of water sufficient for the hydrolysis process of the organosilicon compound, ie more than 0.5 mol of water per mol of the group (eg alkoxy group) to be hydrolyzed, preferably with an acid catalyst By the silane compound described above. Examples of acids that may be added include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, organic acids such as carboxylic acid, organic sulfonic acid, or the like, or acidic ion exchangers, and the pH during the hydrolysis reaction is generally 2 to 4.5. , Preferably it is 3.

Once the reactants are combined, an increase in temperature is generally observed. In certain instances, it may be necessary to introduce external heat, for example, by heating the mixture to 40-50 ° C. to initiate the reaction. In general, care must be taken to prevent the reaction temperature from exceeding 55 ° C. The reaction time is generally relatively short, typically less than 1 hour, for example 45 minutes.

The silane compound may be condensed to provide a polymer having a weight average molecular weight (M _w ) of generally 100 to 20,000 g / mol, preferably 200 to 10,000 g / mol, particularly preferably 500 to 1500 g / mol. An example of a method for measuring this molar mass is NMR spectroscopy.

Examples of ways to terminate the condensation reaction include cooling the temperature below 0 ° C. or increasing the pH using a suitable base such as an alkali metal hydroxide or an alkaline earth metal hydroxide.

For further operation, part of the water / alcohol mixture, volatile acids, can be removed from the reaction mixture, for example by distillation.

Suitable organic solvents such as alcohols such as ethanol, methanol, isopropanol, butanol, ethers such as diethyl ether, dioxane, ethers and esters of polyols such as ethylene glycol, propylene glycol Or ethers and esters of these compounds, hydrocarbons such as aromatic hydrocarbons, ketones such as acetone, methyl ethyl ketone, may then contain about 15 to about 15 percent by weight of the solids, based on the total weight of the mixture. It can be used to adjust to 35% by weight. Ethanol and / or 2-propanol are particularly preferred as solvents.

It has also proved advantageous to add to the coating composition a solvent which normally solvates the plastic intended as the coating substrate. When using polymethyl methacrylate (PMMA) as the substrate, for example, adding a solvent such as toluene, acetone, tetrahydrofuran in an amount of 2 to 20% by weight based on the total weight of the composition. Valid The water content is generally set at 5 to 20% by weight, preferably 11 to 15% by weight, based on the total weight of the composition.             

To improve storage stability, the pH of the aqueous siloxane lacquer can be adjusted in the range of 3 to 6, preferably 4.5 to 5.5. For example, additives may also be added for this purpose, in particular to propionamide, which are described in EP 0 073 911.

The siloxane lacquers which can be used according to the invention are formulated with a curable catalyst, for example zinc compounds and / or other metal compounds, such as cobalt compounds, copper compounds or calcium compounds, in particular their octoates or naphthenates. It may be included in the form. The content of the curable catalyst is generally from 0.1 to 2.5% by weight, in particular from 0.2 to 2% by weight, based on the total siloxane lacquer, but not limited thereto. By way of example, zinc naphthenate, zinc octoate, zinc acetate, zinc sulfate and the like can be mentioned in particular.

Acriplex) 100 및 아크리플렉스 180 SR이라는 상품명으로 시판중이다.The siloxane lacquers described above were acriflexed from Rohm GmbH & Co. KG.

Acriplex) 100 and Acriplex 180 SR are commercially available.

The siloxane lacquers described above can be applied to the plastic substrate using any known method. Among these are immersion processes, spraying processes, doctoring, flow coating, and application by rollers or rolls.

In general, the siloxane lacquers applied in this manner are relatively short, for example within 2 to 6 hours, generally within about 3 to 5 hours, at relatively low temperatures, for example at 70 to 110 ° C, preferably Curing at about 80 ° C. can provide a coating that is excellent in scratch resistance and adhesion.

The thickness of the siloxane coating (a) layer is relatively insignificant. However, after curing, the variable is generally in the range of 1 to 50 μm, preferably 1.5 to 30 μm, particularly preferably 3 to 15 μm, but not limited thereto. The layer thickness of coating (a) and / or coating (b) can be measured via scanning electron microscopy (SEM).

In one specific aspect of the invention, the polar component of the surface energy is preferably 8 mN / m or less, particularly preferably 6 mN / m or less after curing of the first siloxane layer.

In one preferred embodiment of the present invention, the silicon content of the siloxane coating (a) after curing is 20% by weight or more, preferably 30% by weight or more, based on the total weight of the coating, but is not limited thereto. The carbon content is preferably at most 36% by weight, in particular at most 25% by weight, based on the total weight of the coating. These contents are yachts. It can be measured by elemental analysis using the J. Liebig method or atomic absorption spectroscopy (AAS).

After curing of the first siloxane coating, the surface is activated by increasing the polar component of the surface energy of the cured siloxane coating to a value of at least 10 mN / m. It is particularly desirable for the polar component of the surface energy to increase above 15 mN / m.

Surface energy is measured by the Onesses-Wendt-Rabel & Kaeble method. To this end, the test liquids used are water [ST 72.1 mN / m], formamide [ST 56.9 mN / m], diiodomethane [ST 50.0 mN / m] and α-bromonaphthalene [ST 44.4 mN / m ] A series of measurements is performed using the Busscher series of standards. The measurement is carried out at 20 ° C. The surface tension, polar component and dispersion component of these test liquids are known and they are used in the calculation of the surface energy of the substrate.

Surface energy can be measured using a G40 contact angle measurement system from Kruss, Hamburg, which is the method described in the user guidance of the G40 contact angle measurement system 1993. As to the calculation method, see A.W. Neumann, Uber die Messmethodik zur Bestimmung grenzflachenenergetischer Grossen (Measurement methods for determining surface energy variables), Part I, Zeitschrift fur Phys. Chem., Vol. 41, pp. 339-352 (1964), and A.W. Neumann, Uber die Messmethodik zur Bestimmung grenzflachenenergetischer Grossen (Measurement methods for determining surface energy variables), Part II, Zeitschrift fur Phys. Chem., Vol. 43, pp. 71-83 (1964).

Various physical and chemical methods are suitable for activating the siloxane underlaquer. Among these are chemical methods, especially surface treatment with an aqueous solution, corona treatment, flame treatment, plasma treatment or atmospheric plasma treatment. In this context, chemical methods and corona treatments are preferred.

By treating the substrate coated with the siloxane lower lacquer, preferably with a liquid, a reagent, activation can occur by chemical means. Here, it is desirable that the initial etching process only affect the top atomic layer of the siloxane lacquer. In one particular embodiment, the surface is treated with an alkaline solution having a pH of at least 10, preferably at least 12.

For example, substrates coated with siloxane lacquers can be treated with aqueous and / or alcoholic solutions of alkali metal hydroxides. Preferred alcohols are methanol, ethanol, propanol and / or butanol. The concentration of the alkali metal hydroxide is preferably 1 to 20% by weight, in particular 2 to 10% by weight, based on the weight of the etching solution. In particular, alkali metals are lithium, sodium, potassium, rubidium and / or cesium. Of these, sodium and / or potassium are preferred.

The duration of exposure of the alkaline solution depends on the pH and therefore can be within a wide range. However, a few minutes is usually sufficient. The period of exposure to the alkaline solution is particularly preferably in the range of 30 seconds to 60 minutes, in particular 1 minute to 10 minutes. By way of example, this surface treatment may be terminated by neutral washing or addition of acid.

Any known method can be used to apply the alkaline solution to the siloxane coating. These methods have been described above.

In addition, the polar component of the surface energy can be increased by corona treatment. By way of example, this method is described in EP 1 180 426. The treatment period depends on the energy used and is preferably 1 to 20 seconds, in particular 2 to 5 seconds. By way of example, generators suitable for corona treatment can be purchased from Softal Electronic GmbH, Hamburg, and can be operated in a frequency range of 20 to 30 kHz (generator 3005).

After activation of the first siloxane layer, where no photocatalytic content is present, a second layer comprising TiO ₂ particles is applied.

The lacquer for producing the second layer may be substantially the same as the first siloxane lacquer, but it is necessary to introduce photocatalytic TiO ₂ particles.

For example, lacquers of this type can be prepared by mixing the siloxane lacquers described above with an aqueous and / or alcoholic composition comprising TiO ₂ particles.

Particularly suitable coating compositions are in particular compositions comprising colloidal dispersed SiO ₂ particles. These particles preferably have the same size as the TiO ₂ particles described below. Dispersions of this type can be prepared in particular by sol-gel processes which condense tetraalkoxysilanes and / or tetrahalosilanes.

Compositions of this type comprising TiO ₂ particles are known in particular from EP 0 826 663, EP 0 850 203 and EP 1 022 318. Compositions of this type are also, by way of example, by Showa Denko Kabushiki Kaisha, Japan, under the trade name NTB 30A, or by Todo Ltd., Japan. Commercially available.

TiO ₂ particles are photocatalytic. Thus, at least some of the TiO ₂ particles are in the form of brookite and / or anatase. Particle size is not critical, but transparency depends on particle size. The size of the particles is preferably 300 nm or less, in particular 1 to 200 nm, preferably 1 to 50 nm.

A second layer comprising TiO ₂ particles can be applied and cured by the method described above.

In one specific embodiment, the amount of TiO ₂ particles present in the second coating is from 0.01 to 90% by weight, preferably from 0.1 to 75% by weight, based on the total weight of the second coating after curing.

The thickness of the siloxane coating (b) comprising TiO ₂ particles is likewise not important. After curing, the thickness is generally in the range of 0.05 to 2 mu m, preferably 0.1 to 1 mu m.

In one particular embodiment of the plastic article, the total layer thickness of the coating (a) and the coating (b) after curing is 2 to 30 μm, in particular 3 to 15 μm.

The plastic article of the present invention, provided with a photocatalyst coating, has a high scrub resistance. Scrub resistance according to DIN 53778 is preferably at least 10,000 cycles, in particular at least 15000 cycles, particularly preferably at least 20,000 cycles.

In one particular embodiment of the invention, the plastic product is transparent and the transparency τ _{D65 / 10 according} to DIN 5033 is at least 70%, preferably at least 75%.

The plastic product preferably has an elastic modulus in accordance with ISO 527-2 of 1000 MPa or more, in particular 1500 MPa or more, but is not limited thereto.

Plastic products of the invention are generally very weather resistant. For example, weather resistance in accordance with DIN 53387 (Xenotest) is more than 5000 hours.

Even after extended UV irradiation for more than 5000 hours, the yellowing index according to DIN 6167 (D65 / 10) of the preferred plastic product is 8 or less, preferably 5 or less, but not limited thereto.

By way of example, the plastic products of the invention can be used in the construction sector, in particular for the production of greenhouses or greenhouses for houses or as sound barriers.

The present invention is explained in more detail below by Examples or Comparative Examples, but the present invention is not intended to be limited to these Examples.

Example 1

Acriplex 100 SR)를 제공하였으며, 경화 후의 락커의 층 두께는 7.5㎛이었다.Scratch-resistant lacquer on PMMA sheet of 150 × 350 × 3mm

Acriplex 100 SR), and the layer thickness of the lacquer after curing was 7.5 mu m.

After curing of the lacquer, the polar component of the surface energy was 5.5 mN / m. Thereafter, the surface was treated with 5% KOH water / ethanol mixture (1: 3 weight ratio) for 5 minutes, followed by neutral washing. Surface energy was measured using a G40 contact angle measurement system from Cruces, Hamburg. The test liquids used were water [ST 72.1 mN / m], formamide [ST 56.9 mN / m], diiodomethane [ ST 50.0 mN / m] and alpha-bromonaphthalene [ST 44.4 mN / m]. The polar component of the surface energy was 15.3 mN / m.

After activation, the flow coating was applied to apply a colloidal solution (3: 1 mixture of NTB 30A (TiO ₂ ) and NTB 30B (SiO ₂ ) commercially available from Showa-Denko) containing TiO ₂ particles and SiO ₂ particles. Was used. The fluidity of the lacquer and the adhesive was good. The resulting coating was cured at 80 ° C. for 3 hours.

A Gardner M 105 / A wet scrub tester was used for the scratch resistance of the coating in the DIN 53778 wet scrub test. The measured value was 20,000 cycles.

Example 2

Example 1 was repeated essentially, but NaOH was used instead of KOH. The polar component of the surface energy was 12.8 mN / m.

The flowability and adhesion of the second coating were likewise good and the measured scratch resistance was 15000 cycles.

Example 3

Example 1 was repeated essentially, with the first coating activated by corona treatment. Here, the sheet was passed four times at 1 m / min through a corona system (Sophthalic Electronics GmbH, Hamburg, high frequency range from 20 to 30 kHz).

The flowability and adhesion of the second coating were likewise good and the measured scratch resistance was 12000 cycles.

Comparative Example 1

Example 1 was repeated essentially, but H ₃ PO ₄ was used instead of KOH. The polar component of the surface energy was 6.5 mN / m.

Scratch resistance could not be measured because the fluidity and adhesiveness of the second coating were too inferior.

Comparative Example 2

Example 1 was essentially repeated but no activation occurred. The polar component of the surface energy was 5.5 mN / m.

Scratch resistance could not be measured because the fluidity and adhesiveness of the second coating were too inferior.

Comparative Example 3

Example 1 was essentially repeated with the first coating incompletely cured. Curing time was 0.5-2.0 hours at 80 degreeC.

The flowability of the coating solution over the partially cured layer was unsatisfactory, and the curing of the second layer provided a mechanically unstable coating that lacked scratch resistance and could be damaged by rubbing with a cloth. The scratch resistance could not be measured.

Claims (21)

a) applying the siloxane coating (a) to a plastic substrate and then curing the coating, b) increasing the value of the polar component of the surface energy of the cured siloxane coating to at least 10 mN / m, c) coating (b) comprising photocatalyst TiO ₂ particles to the coating obtained in step b) and curing the coating (b) Self-cleaning plastic products obtainable by The plastic article of claim 1, wherein the plastic substrate comprises a cycloolefin copolymer, polyethylene terephthalate, polycarbonate, and / or poly (meth) acrylate. The plastic article of claim 2, wherein the plastic substrate consists of polymethyl methacrylate. The plastic product according to claim 1, wherein the plastic substrate has an impact strength of at least 10 kJ / m 2 in accordance with ISO 179/1. The plastic product according to claim 1, wherein the plastic substrate has a thickness in the range of 1 to 200 mm. The siloxane coating is obtainable by condensing a composition comprising at least 80% by weight of an alkyltrialkoxysilane, based on the content of the condensable silane, according to claim 1. Plastic products. The plastic article of claim 1, wherein the siloxane coating comprises condensable polysiloxane having a molar mass in the range of 500-1500 g / mol. The plastic product according to any one of claims 1 to 3, wherein the proportion of silicon in the siloxane coating (a) is at least 30% by weight, based on the total weight of the coating. The value of the polar component of the surface energy of the siloxane coating (a) according to any one of claims 1 to 3, before increasing the value of the polar component of the surface energy of the siloxane coating (a) to 10 mN / m or more. A plastic product characterized by being lowered to 6 mN / m or less by this curing. 4. The plastic product according to claim 1, wherein the value of the polar component of the surface energy of the siloxane coating (a) is increased by treatment with an alcoholic potassium hydroxide solution after curing. 5. The plastic product according to claim 1, wherein the TiO ₂ particles have a size in the range from 1 to 300 nm. The amount of TiO ₂ particles present in the second coating (b) is from 0.01 to 90 weight based on the total weight of the second coating (b) after curing. Plastic products, characterized in that the range of%. The plastic product according to any one of claims 1 to 3, wherein the layer thickness of the siloxane coating (a) after curing is in the range of 1.5 to 30 µm. The plastic product according to any one of claims 1 to 3, wherein the layer thickness of the coating (b) after curing is in the range of 0.01 to 2 µm. The plastic product according to any one of claims 1 to 3, wherein the layer thickness of the coating (a) and the coating (b) after curing is in the range of 3 to 15 µm. The plastic product according to claim 1, wherein the plastic product according to DIN 53778 has a scrub resistance of 15,000 or more. The plastic product according to claim 1, wherein the elastic modulus according to ISO 527-2 is at least 1500 MPa. Plastic product according to any one of the preceding claims, characterized in that the weather resistance according to DIN 53 387 is at least 5000 hours. Plastic product according to claim 1, characterized in that the transparency according to DIN 5033 is 70% or more. The plastic product according to claim 1, wherein the yellowness index is 5 or less after 5000 hours of UV irradiation. a) applying the siloxane coating (a) to a plastic substrate and then curing the coating, b) increasing the value of the polar component of the surface energy of the cured siloxane coating to at least 10 mN / m, c) coating (b) comprising photocatalyst TiO ₂ particles to the coating obtained in step b) and curing the coating (b) A process for producing a self-cleaning plastic product according to any one of claims 1 to 3, characterized in that