DE4302327A1 - Radiation-curable oligomers as well as liquid, radiation-curable coating mass for the coating of glass surfaces - Google Patents

Description

The present invention relates to rays curable oligomers with several ethylenically unsaturated end groups as well as several urea and possibly Urethane groups per molecule that can be produced from

• a) at least one hydroxy and / or amino function len connection with a functionality between 3 and 4th
• b) at least one compound with 2 hydroxyl and / or Amino groups per molecule,
• c) at least one monoethylenically unsaturated Ver bond with a group with an active water atom of matter per molecule and with a number average Molecular weight between 116 and 1000 and
• d) at least one aliphatic and / or cycloalipha table diisocyanate,

with components a to d incorporated in such quantities be put that

• 1.) the molar ratio of component a to the compo  component b is between 0.1: 1 and 1.1: 1,
• 2.) the molar ratio of component c to the compo nente a is between 2: 1 and 10: 1 and
• 3.) the equivalent ratio of the isocyanate groups Component d to the amino and optionally hydroxyl groups the sum of components a to c between 0.9 and 1.0 is.

The present invention also provides radiation-curable coating compositions that radiate them contain curable oligomers and methods for loading layers of glass surfaces, especially optical ones Glass fibers in which these coating compositions are used become.

Optical glass fibers are of ever increasing importance device in the field of communication as light waves conductor fibers obtained. For this purpose it is absolutely necessary, the glass surface from damp to protect activity and wear and tear. The Glass fibers are therefore directly following their manufacture position with at least one protective lacquer layer Mistake.

For example, it is known from EP-B-114 982 Glass fibers initially with an elastic, but little hard and less tough buffer layer (primer) the base of linear urethane acrylates and then also a radiation-curable topcoat to apply the basis of linear urethane acrylates, which is extremely hard and tough. The two layered structure is said to provide good protection for the glass fa with mechanical stress even at deep Ensure temperatures. Coatings on the The basis of linear urethane acrylates, however, show that  Disadvantage that the mechanical properties of the Coatings, especially the elasticity, still ver are in need of improvement.

Furthermore, EP-A-223 086 has also hardened radiation bare coating agent for the coating of optical Glass fibers known. These coating agents contain as Binder radiation-curable oligomers that can be produced are made of polyether triols or triamines with a average molecular weight from 300 to 4000, polyether diols or diamines with an average molecular weight important from 200 to 4000, OH-functional acrylate monomers ren and diisocyanates, which for the preparation of Molar ratio of triol or oligomers used Triamine to diol or diamine between 2.5: 1 and 20: 1 lies.

This radiation-curable described in EP-A-223 086 Ren coating agents are either as topcoat or used as a one-coat finish. As a primer on the other hand, they are due to a too high modulus of elasticity the hardened coatings are not suitable.

Radiation-curable coating compositions for the coating of optical glass fibers are also in EP-A-209 641 described. These coverings contain a bandage medium a polyurethane oligomer with acrylate end groups, which is based on a polyfunctional core. This Coating compounds can be used as a primer as well can be used as a top coat. Also a single layer Processing is possible.

From the international patent application with the publisher Publication number WO 92/04391 are radiation-curable Coating agent for the coating of optical glass known fibers that are radiation-curable as binders Contain oligomers according to the preamble of the main claim  These coating agents are due to the low modulus of elasticity especially as primers used for glass fibers. On the part of the manufacturers of However, there is a requirement for optical glass fibers that mechanical properties of the coatings further improve. In particular, the buffering effect of the Coatings are further optimized, and the buffers properties should over a wide temperature range stay rich if possible. The Reak activity of the coating compositions not deteriorated and easy assembly of the coated glass fibers are guaranteed.

The present invention is based on the object radiation-curable coating compositions for the coating of glass surfaces, in particular of optical glass fa to provide the compared to the known coating compositions for coatings with verbes lead properties. In particular, the cured coatings provide an improved buffer effect through lower modulus of elasticity with higher tear show elongation values, with the buffer properties approximately over the largest possible temperature range should stay the same. This means that the mechanical properties of the coating with sink deteriorate the temperature as little as possible should. In particular, the modulus of elasticity should be sin rising temperature only as little as possible. The coating masses should be removed as quickly as possible harden. In addition, the coating agent should ver better assembly of the coated glass fibers possible chen. Different in particular at the connection points whose glass fibers it is therefore necessary that the loading layers a reduced adhesion on the glass fiber so as to be easily ent in the connection area to be distant. On the other hand, the Haf  coating on the glass fiber in case of moisture Do not worsen the strain too much to ensure that when the optical fiber ages, none Delamination from moisture exposure occurs.

Surprisingly, the task will shine through curable oligomers with several ethylenically unsaturated end groups as well as several urea and possibly Dissolved urethane groups per molecule that can be produced out

• a) at least one hydroxy and / or amino function len connection with a functionality between 3 and 4th
• b) at least one compound with 2 hydroxyl and / or Amino groups per molecule,
• c) at least one monoethylenically unsaturated Ver bond with a group with an active water atom of matter per molecule with a number average Molecular weight between 116 and 1000 and
• d) at least one aliphatic and / or cycloalipha table diisocyanate,

with components a to d incorporated in such quantities be put that

• 1. the molar ratio of component a to the component b between 0.1: 1 and 1.1: 1, preferably between 0.1 and 0.8,
• 2. the molar ratio of component c to the component a between 2.0: 1 and 10: 1, preferably between 2.5 and 10 lies and  
• 3. the equivalent ratio of the isocyanate groups Component d to the amino and optionally hydroxyl groups the sum of components a to c between 0.9 and 1.0 is.

The radiation-curable oligomers are therefore known records that

• 1. as component a at least one amino group-containing compound a ₁ with a number average molecular weight of more than 4000 to 10,000 and / or at least one amino and / or hydroxyl group-containing compound a ₂ with a number average molecular weight of 400 to 4000 has been used ,
• 2. as component b at least one amino group-containing compound b ₁ with a number average molecular weight of more than 4000 to 10,000 and / or at least one amino and / or hydroxyl group-containing compound b ₂ with a number average molecular weight of 200 to 4000 has been used ,
• 3. the oligomer double bond contents from 0.25 to 0.44 mol / kg and
• 4. at least one amino group-containing compound a ₁ and / or b _{1 has} been used to prepare the oligomers.

The present invention also relates to radiation curable coating compositions which these radiation-curable Contain oligomers, and methods of coating of glass surfaces, in particular of optical glass fa  with which these coating compositions are used.

It is surprising and unpredictable that radiation-curable coating compositions based on the Oligomers according to the invention for coatings with a improved compared to conventional coatings Buffer effect, d. H. lower modulus of elasticity higher elongation at break values at the same time. Before the good buffering effect of the Be is also a part of it layers even at low temperatures, because that Problem of the so-called micro-bends is solved. The coating according to the invention is also distinguished tion by good mechanical properties, such as. B. tensile strength and elongation adapted to the application as well as a reduced adhesion of the coatings on the fiber, which is an improved assembly of the be layered glass fibers. The liability of Coating deteriorates after moisture keitslastung not too strong, so that guaranteed is that with the aging of the optical fiber no release due to exposure to moisture. After all the coating compositions according to the invention cure rapidly.

The following are first the inventive radiation-curable oligomers explained in more detail:

It is essential to the invention that for the preparation of the oligomers compounds a ₁ containing amino groups with a functionality of 3 to 4 and with a number average molecular weight of more than 4000 to 10,000, preferably of more than 4000 to 6000, and / or difunctional, amino group-containing Compounds b ₁ with a number average molecular weight of more than 4000 to 10,000, preferably from more than 4000 to 6000, are used. Compounds having secondary amino groups, in particular polyethers having terminal secondary amino groups, are preferably used as component a ₁ and / or component b ₁ . Especially before given as component a ₁ polyalkoxylated triols with terminal secondary amino groups are used. Examples of compounds having primary amino groups suitable as component a ₁ are the amino-functional compounds derived from polyalkoxylated triols, for example the products commercially available under the name JEFFAMIN® from Texaco, such as, for. B. JEFFAMIN® T 5000.

The secondary amines used as component a ₁ can be prepared, for example, by reacting the corresponding polyamines containing primary amino groups with aliphatic ketones, such as, in particular, methyl isobutyl ketone and subsequent hydrogenation of the resulting ketimine. Polyethers suitable for this reaction and containing primary amino groups are, for example, the products available under the name JEFFAMIN® from Texaco, such as JEFFAMIN® T 5000.

Also suitable as component a ₁ are the products commercially available under the name NOVAMIN® from CONDEA Chemie GmbH, such as. B. NOVAMIN® N 60.

As component b ₁ , for example, the amino-functional compounds available under the name JEFFAMIN® from Texaco, derived from polyalkoxylated diols, such as. B. JEFFAMIN® D 4000, is used. The secondary amines used as component b ₁ can be prepared analogously to the compounds a ₁ by reacting the corresponding polyether containing primary amino groups with aliphatic ketones, such as, in particular, methyl isobutyl ketone, and subsequent hydrogenation of the resulting ketimine. Suitable for this implementation, primary amino groups containing polyethers such. B. the JEFFAMIN® types listed under b ₁ .

Also suitable as component b ₁ are the products commercially available under the name NOVAMIN® from CONDEA Chemie GmbH, such as. B. NOVAMIN® N 50.

As component b ₁ poly alkoxylated diols with terminal secondary amino groups are particularly preferably used.

Furthermore, amino and / or hydroxyl group-containing compounds a ₂ with a functionality of 3 to 4, preferably 3, and with a number-average molecular weight of 400 to 4000, preferably 750 to 2000, can also be used to prepare the oligomers according to the invention.

Examples of suitable amino and / or hydroxyl group-containing compounds a ₂ are polyoxyalkylated triols, such as. B. ethoxylated and propoxylated triols, preferably ethoxylated triols, particularly preferably with a number average molecular weight greater than or equal to 1000. As triols, for example, glycerol or trimethylolpropane are used.

Suitable as component a _{2 are} also the corresponding amino-functional compounds, such as. B. derived from poly alkoxylated triols amino functional compounds. Examples are the products available under the name JEFFAMIN® from Texaco, e.g. B. JEFFAMIN® T 403 and T 3000 and the products available under the name NOVAMIN® from CONDEA Chemie GmbH, e.g. B. NOVAMIN® N 30.

The amino-functional compounds a ₂ can contain both primary and secondary amino groups. In addition, compounds are also suitable which contain both amino and hydroxyl groups.

For the production of the oligomers according to the invention, amino and / or hydroxyl-containing compounds b ₂ , which contain two hydroxyl and / or amino groups per molecule, can also be used.

These compounds b ₂ have number average molecular weights of 200 to 4000, preferably 600 to 2000.

Examples of suitable amino and / or hydroxyl group-containing compounds b ₂ are polyoxyalkylene glycols and polyoxalkylenediamines, alkylene groups having 1 to 6 carbon atoms being preferred. For example, polyoxethylene glycols with a number average molecular weight of 1000, 1500, 2000 or 2500 and polyoxypropylene glycols with the corresponding molecular weights and polytetramethylene glycols are suitable. Polyethoxylated and polypropoxylated diols can also be used, such as. B. the ethoxylated or propoxylated derivatives of butanediol, hexanediol, etc. Also usable are polyester diols which, for. B. can be produced by reaction of the glycols already mentioned with dicarboxylic acids, preferably aliphatic and / or cycloaliphatic dicarboxylic acids, such as. B. hexahydrophthalic acid, adipic acid, azelaic, sebacic and glutaric acid and / or their alkyl-substituted derivatives. Instead of these acids, their anhydrides, if they exist, can also be used.

Polycaprolactone diols can also be used. This pro Products are included, for example, by implementing a ε-caprolactone with a diol. Such products are in U.S. Patent 3,169,945.

The polylactone diols obtained by this implementation  holds, are characterized by the presence of a terminal due hydroxyl group and by recurring poly portions of ester derived from the lactone. These recurring molecular parts can be of the formula

correspond in which n is preferably 4 to 6 and Substituent hydrogen, an alkyl radical, a cycloalkyl radical or an alkoxy radical, with no substituent contains more than 12 carbon atoms and the whole Number of carbon atoms of the substituents in the Lactone ring does not exceed 12.

The lactone used as the starting material can be a sweet lactone or any combination of Lactones, this lactone being at least 6 carbons should contain atoms in the ring, for example 6 up to 8 carbon atoms and at least 2 water Substituents present on the carbon atom should be. The one used as the starting material Lactone can be represented by the following general formula are:

in which n and R have the meaning already given. The invention for the production of the poly preferred lactone ester diols are the caprolactones,  where n is 4. The most preferred Lactone is the substituted ε-caprolactone, in which n has the value 4 and all R substituents are hydrogen are. This lactone is particularly preferred because it is in large quantities are available and covers with drawn properties. In addition, ver other lactones individually or in combination to be used. Examples of implementation with the Aliphatic diols suitable for lactone are already the listed above for the reaction with the carboxylic acids ten diols.

Of course, the corresponding diamines and compounds with one OH and one amino group can also be used as component b ₂ . Examples of suitable compounds are the products available under the name JEFFAMIN® D 230, D 400, D 2000, ED 600, ED 900, ED 2001, ED 4000, BUD 2000 and C 346 from Texaco as well as those under the name NOVAMIN® products available from CONDEA Chemie GmbH, such as B. NOVAMIN® N 10, N 20 and N 40.

A mixture of is preferred as component b ₂

• b ₂₁ ) 0 to 90 mol% of at least one polyether diol and
• b ₂₂ ) 10 to 100 mol% of at least one modified polyether diol
  α) at least one polyether diol
  β) at least one aliphatic and / or cycloaliphatic dicarboxylic acid and
  γ) at least one aliphatic, saturated compound with an epoxy group and with 8 to 21 C atoms per molecule,

used, the sum of the proportions of components b ₂₁ and b ₂₂ and the sum of the proportions of components α to γ each being 100 mol%.

To produce the modified polyether diols after The usual methods are the components α to γ in such amounts that the equivalent ratio the OH groups of component α to the carboxyl groups component β between 0.45 and 0.55, preferably 0.5, lies and that the equivalent ratio of the epoxy group pen of component γ to the carboxyl groups of the compo nente β is between 0.45 and 0.55, preferably 0.5.

Examples of suitable polyether diols b ₂₁ and α are the polyoxyalkylene glycols already listed, the alkylene groups having 1 to 6 carbon atoms. Component b _{21 is} preferably polyoxypropylene glycols with a number average molecular weight between 600 and 2000. Polyoxybutylene glycols (poly-THF) with a number-average molecular weight of <1000 are preferably used as component α.

As component β are preferably aliphatic and cycloaliphatic dicarboxylic acids with 8 to 36 carbon atoms used per molecule, such as. B. hexahydrophthalic acid. Epoxy, for example, is suitable as component γ dated, monoolefinically unsaturated fatty acids and / or Polybutadienes.

Preferred components γ are glycidyl ester branched monocarboxylic acids, such as. B. the glycidyl ester of versatic acid.

The compounds a ₁ , a ₂ , b ₁ and b ₂ are preferably used in amounts such that the molar ratio of the hydroxyl and / or amino groups of components a ₂ and b ₂ to the amino groups of components a ₁ and b _{1 is} between 0 and 10, preferably between 0.1 and 3.

To introduce the ethylenically unsaturated groups in the polyurethane oligomer become monoethylenic saturated compounds with a group with an acti ven hydrogen atom used, which is a number average Molecular weight of 116 to 1000, preferably 116 to 400. As examples of suitable components c be z. B. Hydroxyalkyl esters ethylenically unsaturated ter carboxylic acids, such as. B. Hydroxyethyl acrylate, Hy hydroxypropyl acrylate, hydroxyutylacrylate, hydroxyamyl acrylate, hydroxyhexyl acrylate, hydroxyoctyl acrylate, and the corresponding hydroxyalkyl esters of meth acrylic, fumar, maleic, itacone, croton and isocroton called acid, but the hydroxyalkyl esters acrylic acid are preferred.

Adducts of are also suitable as component c Caprolactone and one of the above-mentioned hydroxyal alkyl esters of ethylenically unsaturated carboxylic acids. Before adducts of the hydroxyalkyl esters of acrylic are added acid with a number average molecular weight of 300 to 1000 used.

For the preparation of the oligomers according to the invention as Component d is suitable for aliphatic and / or cyclo aliphatic diisocyanates such as e.g. B. 1,3-cyclopentane, 1,4-cyclohexane, 1,2-cyclohexane diisocyanate, 4,4'-methy len-bis- (cyclohexyl isocyanate) and isophorone diisocyanate, Trimethylene, tetramethylene, pentamethylene, hexa methylene and trimethyl hexamethylene 1,6 diisocyanate and those in EP-A-204 161, column 4, lines 42 to 49 described, derived from dimer fatty acids Diisocyanates.  

Isophorone diisocyanate and Trimethylhexamethylene 1,6 diisocyanate.

Components a to d are used to produce the oli gomers are used in such amounts that

• 1. the molar ratio of component a to the component b between 0.1: 1 and 1.1: 1, preferably between 0.1 and 0.8,
• 2. the molar ratio of component c to the component a between 2.0: 1 and 10: 1, preferably between 2.5 and 10, lies and
• 3. the equivalent ratio of the isocyanate groups Component d to the active hydrogen atoms the components a plus b plus c between 0.9 and 1.0 lies.

The oligomers according to the invention can differ be manufactured in a way. For example as possible, first the diisocyanate d with the ket to implement ten extension means a and b including the remaining free isocyanate groups implement the ethylenically unsaturated compound c.

It is also possible to produce the oligomers by first part of the isocyanate groups of the compo nente d with the ethylenically unsaturated compound c is implemented and then the rest free isocyanate groups with the chain extender a and b are implemented.

It is also possible to use the polyurethane oligomers according to those described in EP-A-223 086 on page 5 Manufacturing process.  

The polyurethane oligomers are preferred by means of a two-step process made by first the stoichiometric polyaddition of the compo nenten a to d is carried out until more than 85% of the NCO groups of component d have reacted. In this first step, the components ten a to d used in such amounts that the equi valent ratio of the NCO groups of component d to the active hydrogen atoms of components a to c Is 1: 1.

In a second process step, the rest the other components (according to the desired NCO: OH ratio) added and the reaction up to continued sales of the NCO groups <99%. Before more is added in this second process step Component c added and by the addition of this Kom component c the desired NCO: OH equivalent ratio set. In this preferred two step process ren is preferably an adduct as component c Hydroxyethyl acrylate and caprolactone with one pay average molecular weight 300 used.

It is essential to the invention that the urethane oligomers Double bond levels from 0.25 to 0.44 mol / kg before trains 0.3 to 0.44 mol / kg. Furthermore, the Urethane oligomers according to the invention are usually tough lenean average molecular weights from 2000 to 20,000, be preferably 3500 to 16 000 (measured with GPC against poly styrene standard), weight average molecular weights of 8,000 to 100,000; preferably 10,000 to 40,000 (according to with GPC against polystyrene standard) and a radio tionality from 2 to 4, preferably 2.5 to 3.0, each per average statistical polymer molecule.  

The oligomers of the invention are called film-forming Component A in radiation-curable coating compositions puts. The coating compositions usually contain 10 to 78 wt .-%, preferably at least 15 wt .-% and be particularly preferably 63 to 73% by weight, in each case based on the total weight of the coating composition, this invention according oligomers.

As a further component, the coating compositions 0 to 60 wt .-%, preferably 0 to 50 wt .-%, each based to the total weight of the coating mass, at least another ethylenically unsaturated oligomer B contain. In addition to unsaturated polyesters, polyester Above all, acrylates and acrylate copolymers Urethane acrylate oligomers other than those used as components te A urethane acrylate oligomers used. Due to the type and amount of this component B, the Properties of the hardened coating targeted to be controlled. The higher the proportion of this component B is, the higher is the modulus of elasticity in general the cured coating. Component B is therefore added to the coating compositions especially when the coating compositions are used as topcoat. Of the Influence of this component B on the properties of the resulting coating is the expert but be knows. The most favorable amount can be used can be easily determined using fewer routine attempts. This used as component B ethylenically saturated polyurethanes are known. You can get th by reacting a di- or polyisocyanate tes with a chain extender from the group of the diols / polyols and / or diamines / polyamines and closing implementation of the remaining free isocyanate groups with at least one hydroxyalkyl acrylate or Hydroxyalkyl esters of other ethylenically unsaturated Carboxylic acids.  

The amounts of chain extender, di or poly Isocyanate and hydroxyalkyl ester of an ethylenically un saturated carboxylic acid are chosen so that

• 1. the equivalent ratio of the NCO groups to the reactive groups of the chain extender (Hydroxyl, amino or mercaptyl groups) between 3: 1 and 1: 2, preferably 2: 1, lies and
• 2. the OH groups of the hydroxyalkyl esters of ethylenic unsaturated carboxylic acids in stoichiometric Amount based on the free isocyanate groups of the prepolymer from isocyanate and chain extensions agents are available.

It is also possible to produce polyurethanes B. len by first part of the isocyanate groups Di- or polyisocyanates with at least one hydroxy alkyl ester of an ethylenically unsaturated carboxylic acid is implemented and the remaining isocyanate groups closing with a chain extender be set. In this case, too, the quantities Chain extenders, isocyanate and hydroxyal alkyl esters of unsaturated carboxylic acids so chosen that the Equivalent ratio of the NCO groups to the reactive Group of chain extender between 3: 1 and 1: 2, preferably 2: 1, and the equivalent ratio of the remaining NCO groups to the OH groups of the hydroxyalkyl ester is 1: 1.

Of course, all intermediate forms are also of these two methods possible. For example part of the isocyanate groups of a diisocyanate first reacted with a diol, then another part of the isocyanate groups with the hydroxy  alkyl ester of an ethylenically unsaturated carboxylic acid and then the remaining isocyanate groups can be reacted with a diamine.

These different manufacturing processes for polyurethanes are known (cf. for example EP-A-294 161) and therefore do not require a more detailed description.

For the production of these urethane acrylate oligomers B suitable connections are already at the manufacturer position of component A used compounds and also those mentioned in DE-OS 38 40 644 Links.

Especially when using the over invention tensile masses as topcoat are used to manufacture the Urethane acrylate oligomers prefer aromatic structure components used. Are particularly preferred in in this case 2,4- and 2,6-tolylene diisocyanate as Isocyanate component and aromatic polyester polyols based on phthalic acid and isophthalic acid and / or Polypropylene glycol, ethylene glycol and diethylene glycol used as a chain extender.

As a further component, contain the radiation curable their coating compositions are at least one ethylenically un saturated monomeric and / or oligomeric compound C, usually in an amount of 20 to 50 wt .-%, be preferably from 22 to 35 wt .-%, each based on the Total weight of the coating mass.

By adding these ethylenically unsaturated ver Binding C are the viscosity and the curing amount speed of the coating masses as well as the mechanical Properties of the resulting coating controls how this is known to the expert and with  is described for example in EP-A-223 086 and on which is referred to for further details.

As examples of monomers that are used can be ethoxyethoxyethyl acrylate, N-vinylcapro lactam, N-vinylpyrrolidone, phenoxyethyl acrylate, Di methylaminoethyl acrylate, hydroxyethyl acrylate, butoxy ethyl acrylate, isobornyl acrylate, dimethylacrylamide and Called dicyclopentyl acrylate. Are also suitable Di- and polyacrylates, such as. B. butanediol diacrylate, Hexanediol diacrylate, trimethylol propane and triacry lat, pentaerythritol tri and tetra acrylate, the analog Acrylic acid esters of alkoxylated, especially ethoxy lated and propoxylated, polyols, such as. B. Glyce rin, trimethylolpropane and pentaerythritol, with one number average molecular weight from 266 to 1014, as well as the long chains described in EP-A-250 631 gene linear diacrylates with a molecular weight of 400 to 4000, preferably from 600 to 2500. Example the two acrylate groups can be separated by a poly oxybutylene structure to be separated. Can be used also 1,12-dodecyl diacrylate and the reaction pro product of 2 moles of acrylic acid with one mole of a dimer fatty alcohol, which generally has 36 carbon atoms.

Mixtures of those just described are also suitable Monomers. Phenoxyethyl acrylate and hexane are preferred diol diacrylate, N-vinyl caprolactam and tripropylene gly koldiacrylat used.

The more common in the coating compositions of the invention in an amount of 2 to 8% by weight, preferably 3 up to 5 wt .-%, based on the total weight of the over tensile mass, photoinitiator used varies with the jet used to harden the coating agent lung (UV radiation, electron radiation, visible  Light). Preferred over the invention tensile masses hardened by means of UV radiation. In this Fall usually photoinitiators on ketone Basis used, for example, acetophenone, benzophe non, α, α-dimethyl-α-hydroxyacetophenone, diethoxyaceto phenon, 2-hydroxy-2-methyl-1-phenylpropan-1-one, Hy droxypropylphenyl ketone, m-chloroacetophenone, propiophe non, benzoin, benzil, benzil dimethyl ketal, anthrachi non, thioxanthone and thioxanthone derivatives and triphe nylphosphine u. a. as well as mixtures of different photos initiators.

In addition, the coating compositions can, if necessary, still be conventional Auxiliaries and additives included. These become nasty Usually in an amount of 0 to 4 wt .-%, preferred 0.5 to 2.0 wt .-%, each based on the total Ge importance of the coating composition. Examples of the like substances are leveling agents and plasticizers.

The coating compositions can be applied using known applications tion methods such. B. spraying, rolling, flooding, Dip, knife or brush, applied to the substrate be brought.

The paint films are cured by means of radiation, preferably by means of UV radiation. The plants and bedin Conditions for these hardening methods are from the litera known (see e.g. R. Holmes, U.V. and E.B. Curing Formulations for Printing Inks, Coatings and Paints, SITA Technology, Academic Press, London, United Kindom 1984) and need no further description.

The coating compositions are suitable for coating ver various substrates, for example glass, wood, Metal and plastic surfaces. In particular, be but for coating glass surfaces, esp  preferably used of optical glass fibers.

The present invention is therefore also an object a method for coating a glass surface, at to which a radiation-curable coating composition is applied and is cured by means of UV or electron radiation, which is characterized in that as radiation-curable Coating composition the coating compositions of the invention be set.

The method according to the invention is particularly good suitable for the coating of optical glass fibers. The coating compositions of the invention can ins especially as a primer, but possibly also as a top coat a two-coat finish on the glass fibers be brought. When using the coating compounds the cured coatings are used as a primer usually a modulus of elasticity (at 2.5% elongation and Room temperature) of less than 10 MPa.

When using the coating compounds as top coat usually have the cured coatings a modulus of elasticity (at 2.5% elongation and room temperature tur) from 500 to 1000 MPa.

The invention is illustrated in the following examples explained. All information about parts and percentages are weights unless expressly stated other is determined.

Production of a modified polyether diol

In one with stirrer, inert gas inlet and thermo guide The equipped kettle becomes 51.1 parts polyte trahydrofuran with a number average molecular weight  weight of 1000 and an OH number of 118 mg KOH / g and 19.1 parts of hexahydrophthalic anhydride to 120 ° C warms and kept at this temperature until an acid number of 102 mg KOH / g is reached. Then are 0.02% chromium octoate, based on the weight of the Mixture of poly-THF, hexahydrophthalic acid and Glyci dylester of versatic acid and 29.7 parts of glyci dylesters of versatic acid with an epoxy equivalent weight of 266 added. The mixture is so long heated to 120 ° C until the reaction product is an epoxy equivalent weight <20,000, an acid number of 4 mg KOH / g and has an OH number of 60 mg KOH / g.

The modified polyether diol has an average molecular weight M _n = 1860 (calculated from the OH number), a M _n ≈ 1500 determined by means of GPC and an M _W / M _n = 1.67. The viscosity of an 80% solution in butyl acetate is 3.8 dPa · s (measured at 23 ° C with the plate / cone viscometer).

Comparative Example 1

As in example 1 of international patent applications tion WO 92/04 391 are described in a with Rüh rer, inlet devices, thermal sensors and air inlet provided boiler 0.35 mol of a commercially available ethoxylated trimethylolpropane with a number average leren molecular weight of 1014, 0.65 mol commercial ches polyoxyropylene glycol with a number average Molecular weight of 600, 0.65 mol of the above described a modified polyether diol, 1.75 mol hydroxy ethyl acrylate, 0.05% dibutyltin dilaurate (based on the total weight of the sum of components a, b, c and d), 0.1% 2,6-di-tert-butylcresol (based on the Ge total weight of the sum of components a, b, c and d)  and 30 ppm phenothiazine (based on total weight submitted the sum of components a, b, c and d) and heated to 60 ° C. After that, 2.70 moles of isophorone diisocyanate metered in at 50 ° C. After that is based on a theoretical with phenoxyethyl acrylate Solids of 90% (sum of components a to d) diluted and the temperature kept at 60 ° C for so long, until an NCO value of 1% is reached. Then be 0.05% dibutyltin dilaurate and 0.51 moles of a trade usual hydroxyethyl acrylate caprolactone oligomers with a number average molecular weight of 344 (Han product TONE M 100 from Union Carbide) added a temperature of 80 ° C and the temperature kept at 80 ° C until an NCO value of <0.1% is reached. The oligomer thus obtained has a double bond content of 0.6 mol / kg and a Functionality from 2.5 up.

A 40% solution (based on the theoretical Solids content) of the oligomer 1 obtained in Phe noxyethyl acrylate has a viscosity of 4.9 dPa · s (measured at 23 ° C with the plate and cone viscometer).

From 66.8 parts of the urethane oligo described above mers 1, 29.3 parts phenoxyethyl acrylate and 3.9 parts α, α-Dimethyl-α-hydroxyacetophenone is made by mixing a radiation-curable coating composition 1 is produced. Well cleaned (especially fat-free) glass plates (Width × length = 98 × 161 mm) are bordered with tesa Krepp®-KLebeband No. 4432 (width 19 mm) taped and the coating composition 1 doctored (dry film thickness 180 µm).

The curing takes place with the help of UV radiation system, equipped with two Hg medium pressure lamps of 80 W / cm lamp power at a belt speed  speed of 14 m / minute, in 1 pass at full load drifted.

The irradiated dose is 0.15 J / cm ² (measured with the UVICURE dosimeter, System EIT from Eltosch).

The results of the modulus of elasticity at 0.5 and 2.5 % Elongation (according to the DIN 53 455 standard) and the Elongation at break test results are shown in Table 3 shown. In addition, the glass is over in Table 3 transition temperature (measured using the DMTA = Dyna mixed-mechanical-thematic analysis) and the results the adhesion test before and after exposure to moisture shown. The liability check was carried out according to DIN standard 53 289.

example 1

In the boiler described in Comparative Example 1 1.3 mol of the above-described modified Polyether diols, 1.75 mol hydroxyethyl acrylate and 0.51 mol of a commercially available hydroxyethyl acrylate caprolac clay oligomers with a number average molecular weight weight of 344 (commercial product TONE M 100 from the company Union Carbide) with 0.05% dibutyltin dilaurate (purchased on the total weight of the sum of components a, b, c and d), 0.1% 2,6-di-tert-butylcresol (based on the Total weight of the sum of components a, b, c and d) and 50 ppm phenothiazine (based on total weight the sum of components a, b, c, d) under one Protective gas atmosphere (nitrogen / air = 3/1) submitted and heated to 60 ° C. Then 2.70 mol of isophorone diisocyanate metered in over the course of 2.5 h and the temperature temperature at 60 ° C until an NCO value of  1.5% is reached. Then it is heated to 80 ° C and the temperature was held at 80 ° C until a NCO value of 0.9% (theoretically 0.82%) is reached. A 40% solution (based on the theoretical Solids content) of the product obtained in phenoxy Ethyl acrylate has a viscosity of 3.6 dPa · s (measured at 23 ° C with the plate and cone viscometer). Then at a temperature of 60 ° C 0.35 mol a commercially available propoxylated glycerin with an average of 3 secondary amino groups per mole cool (number average molecular weight 5250, amino equi valent weight 2220 g, content of primary amino groups <0.02 mmol / g, commercial product NOVAMIN® N60 from the company Condea Chemie GmbH) dosed so that the temperature Not exceed 65 ° C. The temperature is getting long kept at 60 ° C until (possibly with <10% of the initial amount of polyether triamine to NCO content <0.1% len) the NCO content is <0.1%. The so obtained The oligomer has a double bond content of 0.42 mol Double bonds / kg oligomer and a functionality of 2.5 (average number C = C / molecule). A 40% Solution (based on the theoretical solids content) of the oligomer obtained in phenoxyethyl acrylate a viscosity of 4.1 dPa · s (measured at 23 ° C with the plate-cone viscometer).

Analogously to Comparative Example 1, 66.8 parts of the urethane acrylate oligomer 2 described above, 29.3 parts phenoxyethyl acrylate and 3.9 parts α, α-dimethyl-α-hydroxyacetophenone by mixing one radiation-curable coating mass 2 produced. The coating mass 2 is applied and hardened analogous to comparative example 1. The test results of The coating obtained is shown in Table 3.  

Example 2

A radiation-curable oligomer 3 was produced analogously to Example 1, with the only difference that instead of 0.35 mol of NOVAMIN® N 60, 0.35 mol of a commercially available, propoxylated glycerol with on average 3 primary amino groups per molecule (M _n = 5000, amine equivalent weight 1890 g, commercial product JEFFAMIN® T 5000 from Texaco) were used. After the addition of the isophorone diisocyanate, the temperature was kept at 60 ° C. until an NCO value of 1.8% was reached. Thereafter, the mixture was heated to 80 ° C. and the temperature was kept at 80 ° C. until an NCO value of 0.9% was reached. A 40% solution of the intermediate product thus obtained has a viscosity of 2.9 dPa · s, measured at 23 ° C with the plate and cone viscometer using phenoxyethyl acrylate as solvent. The reaction with the amine is carried out analogously to Example 1. A 40% solution (based on the theoretical solids content) of the oligomer 3 obtained in phenoxyethyl acrylate has a viscosity of 5.1 dPa · s (23 ° C., plate cone Viscometer). The preparation, application and curing of the coating composition 3 is carried out analogously to Example 1. The test results of the coating obtained are shown in Table 3.

Comparative Example 2

Analogously to Example 1, it became a radiation-curable Oligomer 4 produced with the difference that instead 0.35 mol of the polyether triamine with secondary amino groups (NOVAMIN® N 60) in Comparative Example 2 0.35 mol of a commercially available, propoxylated Gly cerins with an average of 3 primary amino groups per  Molecule with a number average molecular weight of 3000 (amine equivalent weight 1060 g, commercial product JEFFAMIN® T 3000 from Texaco) were used. After the addition of the isophorone diisocyanate the temperature was kept at 60 ° C until a NCO value of 2.2% was reached. After that it was flat if heated to 80 ° C and the temperature so long kept at 80 ° C until an NCO value of 0.9% is reached has been. A 40% solution of the intermediate so obtained product of Comparative Example 2 has a viscose of 2.7 dPa · s, measured at 23 ° C with the Plate-cone viscometer using Phe noxyethyl acrylate as a solvent. Implementation with the Amine is carried out analogously to Example 1.

A 40% solution (based on the theoretical Solids content) of the oligomer obtained in phenoxy ethyl acrylate has a viscosity of 4.6 dPa · s, measured at 23 ° C with the plate and cone viscometer. The manufacture, application and curing of the rays curable coating composition 4 is carried out analogously to Example 1. The test results of the coatings obtained are shown in Table 3.

Example 3

In the boiler described in Comparative Example 1 0.65 mol of the above-described modified Polyether diol, 0.35 mol of a commercially available ethoxy lated trimethylolpropane with a number-average Molecular weight of 1000, 1.75 mol of hydroxyethyl acrylate and 0.51 mol of a commercially available hydroxyethyl acrylate Caprolactone oligomers with a number average molecule lar weight of 344 (commercial product TONE M 100 from the company Union Carbide) with 0.05% dibutyltin dilaurate (purchased  on the total weight of components a, b, c and d), 0.1% 2,6-di-tert-butylcresol (based on the total weight of components a, b, c and d) and 50 ppm Phenothiazine (based on the total weight of the compo nenten a, b, c and d) under a protective gas atmosphere (Nitrogen / air = 3/1) and heated to 60 ° C. Then 2.70 mol isophorone diisocyanate in the course metered in from 2.5 h and the temperature at Maintained 60 ° C until an NCO value of 1.5% is reached. A 50% solution of the intermediate so obtained in phenoxyethyl acrylate has a viscosity of 6.7 dPa · s (measured at 23 ° C with the plate-cone visco simeter). Then at a temperature of 60 ° C 0.65 moles of a commercially available propoxylated glyce rins with an average of 2 secondary amino groups per Molecule (number average molecular weight 4150, amine equivalent weight 2350 g, content of primary amino group pen <0.02 mmol / g, commercial product NOVAMIN® N 50 der Condea Chemie GmbH) dosed so that the tempe temperature does not exceed 65 ° C. The temperature will be like this kept at 60 ° C for a long time until (if necessary with <10% quantity of polyether diamine to an NCO content of <0.1% ) the NCO content is <0.1%. Get that tene oligomer 5 has a double bond content of 0.414 mol / kg and a functionality of 2.5. A 40% solution (based on the theoretical solid content) of the oligomer obtained in phenoxyethyl acrylate has a viscosity of 3.7 dPa · s (measured at 23 ° C with the plate and cone viscometer). The manufacture, application and curing of the rays curable coating composition 5 is carried out analogously to Example 1. The test results of the coating obtained are in Table 3 shown.  

Comparative Example 3

Analogously to Example 3, it becomes a radiation-curable oil gomer made with the only difference that instead of 0.65 mol of the polyetherdiamine with secondary ami nogroups with a number average molecular weight of 4150 (NOVAMIN® N 50) now 0.65 mol of a commercially available Lichen polyoxypropylenediamine with primary amino groups with a number average molecular weight of 4000 (Amine equivalent weight 2220 g, commercial product JEFFAMIN® D 4000 from Texaco) were used.

A 40% solution (based on the theoretical Solids content) of the oligomer 6 obtained in Phe noxyethyl acrylate has a viscosity of 6.6 dPa · s (measured at 23 ° C with the plate and cone viscometer). The manufacture, application and curing of the coating mass is analogous to example 1. The test results of the coating obtained are shown in Table 3 posed.

The following abbreviations were used in Table 1:
eth. TMP: ethoxylated trimethylol propane
PE-triamine 1 °: propoxylated glycerin with primary amino groups
PE-triamine 2 °: propoxylated glycerol with secondary amino groups
mod. PE: modified polyether diol
PE-diamin 1 °: polyoxypropylenediamine with primary amino groups
PE-diamin 2 °: polyoxypropylene diamine with secondary amino groups
HEA: 2-hydroxyethyl acrylate
TONE M 100: Hydroxyethyl acrylate caprolactone oligomer
IPDI: isophorone diisocyanate.

Summary of test results

As the comparison of Examples 1 and 2 with Comparative Examples 1 and 2 and the comparison of Example 3 with Comparative Example 3 shows, using chain extenders containing amino groups with a number average molecular weight M _n of more than 4000, the buffering effect of the resulting ends Coating significantly improved. For example, the coatings of Examples 1 and 2 according to the invention have significantly lower modulus of elasticity combined with an increased elongation at break and significantly lower glass transition temperatures compared to the analogue structure of the comparative example 2, which only uses an amino group-containing chain extender with a number-average molecular weight of only 3,000 the use of chain extenders with secondary amino groups (Example 1) brings a further improvement in the mechanical properties of the coatings compared to chain extenders with primary amino groups (Example 2).

Also the comparison of example 3 with the analog one Comparative Example 3, in which instead of the fiction moderate amine with a number average molecular weight from 4150 now a primary amine with a number average ren molecular weight of 4000 was used, confirm improves the mechanical properties of the coatings according to the invention.

Claims (19)

1. Radiation-curable oligomers with several ethylenically unsaturated end groups and several urea and possibly urethane groups per molecule, which have been produced from

• a) at least one amino and / or hydroxyfunctional compound with a functionality between 3 and 4,
• b) at least one compound with two hydroxyl and / or amino groups per molecule,
• c) at least one monoethylenically unsaturated compound with a group with one active hydrogen atom per molecule and with a number average molecular weight between 116 and 1000 and
• d) at least one aliphatic and / or cycloaliphatic diisocyanate,

the components a to d have been used in such amounts that

• 1.) the molar ratio of component a to component b is between 0.1: 1 and 1.1: 1,
• 2.) the molar ratio of component c to component a is between 2: 1 and 10: 1 and
• 3.) the equivalent ratio of the isocyanate groups of component d to the amino and possibly hydroxyl groups of the sum of components a to c is between 0.9 and 1.0,

characterized in that

• 1.) as component a at least one amino group-containing compound a ₁ with a number average molecular weight of more than 4000 to 10,000 and / or at least one amino and / or hydroxyl group-containing compound a ₂ with a number average molecular weight of 400 to 4000 has been used ,
• 2.) at least one amino group-containing compound b ₁ with a number average molecular weight of more than 4000 to 10,000 and / or at least one amino and / or hydroxyl group-containing compound b ₂ with a number average molecular weight of 200 to 4000 has been used as component b,
• 3.) the oligomers have double bond contents of 0.25 to 0.44 101 / kg and
• 4.) at least one amino group-containing compound a ₁ and / or b _{1 has been} used to prepare the oligomers.

2. Radiation-curable oligomers according to claim 1, characterized characterized in that the oligomers Doppelbindungsge hold from 0.3 to 0.44 mol / kg. 3. Radiation-curable oligomers according to claim 1 or 2, characterized in that as component a ₁ amino group-containing compounds with a number average molecular weight of more than 4000 to 6000 and / or as component b ₁ amino group-containing compounds of more than 4000 to 6000 have been used . 4. Radiation-curable oligomers according to one of claims 1 to 3, characterized in that as component a ₂ amino- and / or hydroxyl Verbindun gene having a number average molecular weight of 750 to 2000 and / or as component b ₂ amino and / or hydroxyl-containing compounds having a number average molecular weight from 600 to 2000 and / or as component c compounds with a number average molecular weight between 116 and 400 have been used. 5. radiation-curable oligomers according to any one of claims 1 to 4, characterized in that as component a ₁ and / or b ₁ compounds with secondary amino groups, preferably as component a ₁ polyalkoxy-lated triols with terminal secondary amino groups and / or preferably as Component b ₁ poly alkoxylated diols with terminal, secondary amino groups have been used. 6. Radiation-curable oligomers according to one of claims 1 to 5, characterized in that have been used as component a ₂ and / or b ₂ hydroxyl-containing compounds. 7. Radiation-curable oligomers according to one of claims 1 to 6, characterized in that the molar ratio of the hydroxyl and / or amino groups of components a ₂ and b ₂ to the amino groups of components a ₁ and b ₁ between 0 and 10, preferably is between 0.1 and 3. 8. Radiation-curable oligomers according to one of claims 1 to 7, characterized in that compounds with a functionality of 3 have been used as component a ₁ and / or a ₂ . 9. radiation-curable oligomers according to one of claims 1 to 8, characterized in that the components ten to d have been used in such amounts that

• 1. the molar ratio of component a to component b is between 0.1 and 0.8 and / or
• 2. the molar ratio of component c to component a is between 2.5 and 10.

10. Radiation-curable coating composition, characterized records that they have at least one radiation-curable Contains oligomer according to one of claims 1 to 9. 11. Radiation-curable coating composition according to claim 10, in particular for the buffer coating of optical glass fibers, characterized in that it

• A) 10 to 78% by weight of at least one radiation-curable oligomer according to one of claims 1 to 9,
• B) 0 to 60% by weight of at least one further ethylenically unsaturated oligomer,
• C) 20 to 50% by weight of at least one ethylenically unsaturated monomeric and / or oligomeric compound,
• D) 2 to 8 wt .-% of at least one photoinitiator and
• E) 0 to 4% by weight of conventional auxiliaries and additives

contains, with the% by weight in each case on the Total weight of the coating mass are related. 12. Radiation-curable coating composition according to claim 10, characterized in that it

• A) at least 15% by weight of at least one radiation-curable oligomer according to one of claims 1 to 9,
• B) 0 to 50% by weight of at least one further ethylenically unsaturated oligomer,
• C) 22 to 35% by weight of at least one ethylenically unsaturated monomeric and / or oligomeric compound,
• D) 3 to 5 wt .-% of at least one photoinitiator and
• E) 0.5 the 2.0 wt .-% of common auxiliaries and additives

contains, with the% by weight in each case on the Total weight of the coating mass are related. 13. A method for coating a glass surface, in particular a glass fiber, in which

• 1) a radiation-curable primer is applied and hardened by means of UV or electron radiation and
• 2) a radiation-curable topcoat is applied and cured by means of UV or electron radiation,

characterized in that as a primer and / or top coat a radiation-curable coating composition according to one of claims 10 to 12 becomes. 14. Optical glass fiber, characterized in that it with a radiation-curable coating compound one of claims 10 to 12 is coated.