DE2063129B2 - PAINTING COMPOUNDS HARDENABLE BY IONIZING RADIATION BASED ON ACRYLIC SILOXANE RESIN AND UNSATURED MONOMERS AND METHODS FOR THEIR APPLICATION - Google Patents

Description

(a) 20 to 80 parts by weight of vinyl and / or acrylic monomers and

(b) 80 b _t is 20 parts by weight of a Aqryl siloxane resin obtained by

(1) Reacting a molar proportion of a siloxane with at least two functional ones Groups per molecule in the form of hydroxyl groups and / or alkoxyl groups with a hydroxy acrylate from Cs- to Cn-monohydroxyl esters from divalent CV to Cg alcohols and acrylic acid or Methacrylic acid in sufficient amount so that at least one molecule of the acrylate has a functional group every molecule of the siloxane reacts, and

(2) Reacting the resulting acrylate-siloxane with 0.5- to Ikmotoren parts of a Copolymers of vinyl and / or acrylic monomers, the copolymers

(A) at least one monomer as a component thereof in the form of a Csbis Ctt monohydroxy ester of a dihydric C2 to Cs alcohol and of acrylic acid or methacrylic acid and

(b) a major proportion by weight of the constituent monomers thereof in Form of esters of a monohydric Cr to Ce alcohol and acrylic acid or methacrylic acid and

(c) has 0.2 to 2 hydroxyl groups per 1000 units of molecular weight,

has been made

consists.

2. Paint composition according to claim 1, characterized in that it also contains a pigment and / or contains a filler.

3. A paint composition according to claim 1, characterized in that siloxanes are used as the siloxane functional hydroxyl and / or methoxyl groups were used.

4. Paint composition according to claim 1 to 3, characterized in that the film-forming solution of 35 to 65 parts by weight of the acrylic-siloxane resin and 65 to 35 parts by weight of the monomers.

5. A method for coating a substrate with a coating composition, characterized in that on the surface of the base in an average layer thickness of 0.25 to about 100 μ a film-forming solution of the paint according to claims 1 to 4, applied and on the Surface using an electron beam with an average energy im Range from 100,000 to 500,000 volts is networked.

Electron-curable siloxane-acrylate reaction products are described in German Patent 19 57 356 proposed a

Electron-curable, siloxane-modified polyester coatings are from US patents 34 27 512 and 34 37 513 known

One object of the invention consists in siloxane-containing paint compositions which, by irradiation with Electron beams are curable and have improved adhesion to the substrate whereupon it is cured and which can be tailored to the various degrees of flexibility.

The subject of the invention is a by ionizing

Radiation-curable paint based on acrylic siloxane resin and unsaturated monomers

is characterized in that it consists of a film-forming Solution

(A) 20 to 80 parts by weight of vinyl and / or acrylic monomers and

(b) 80 to 20 parts by weight of an acrylic-siloxane resin, which by

(1) Reacting a molar proportion of a siloxane with at least two functional ones Groups per molecule in the form of hydroxyl

groups and / or alkoxyl groups with a hydroxy acrylate from Cs- to Ci2-monohydroxyl esters of dihydric C2 to Ce alcohols and acrylic acid or methacrylic acid in sufficient amount so that at least one

Molecule of acrylate reacts with a functional group of each molecule of siloxane, and

(2) Reacting the resulting acrylate-siloxane with 0.5 to 1.5 molar proportions of a copolymer of vinyl and / or acrylic monomers, the copolymers

(A) at least one monomer as a component thereof in the form of a Cs- bis C ^ monohydroxy ester of a divalent

gen C2 to Cg alcohol and acrylic acid or methacrylic acid and

(b) a greater proportion by weight of the constituent monomers the same in the form of esters of a monovalent Ci- bis

Ce alcohol and acrylic acid or Methacrylic acid and

(c) has 0.2 to 2 hydroxyl groups per 1000 units of molecular weight,

has been made

consists.
In special embodiments, the paint additionally contains a particulate pigment and / or a filler.

In the context of the invention, there is an improved adhesion. Weather resistance unc Flexibility of the paint film in the electron beam cured coating.

In the context of the invention, the term "paint" refers to the material including pigments and / or particulate! Filler, the binder without pigment and / or filler or only with a seh low content of it, which can be colored if desired. Thus, the binder that ultimately ii a permanent film that is resistant to the effects of weathering is transferred from the total heat

consist of practically the entirety of what is used to form the film or it can be referred to as a substance for pigment and / or particulate material,
in the manufacture of acrylic siloxane resins

, _: ten siloxanes have a reactive

Hydroxyl or alkoxy group, advantageously Ci i) is G * and preferably an alkoxy group with Ci Ci attached to at least two of the silicon atoms

_{a are} iden. The term "siloxane" denotes here

Inheritance ties with a bond

I I

—Si — O — Si [er

—C — O — Si—

'5

20th

the remaining valencies by a hydrocarbon radical a hydrocarbonoxy radical is hydrogen atom, a hydroxyl group or an oxygen atom are saturated, which the silicon atoms with such a valence with another Connect silicon atom. The siloxane can be either cyclic or acyclic. Appropriate cyclic and Acyclic siloxanes for use in the invention are described in the above US patents 34 37 512 and 34 37 513 and in other literature references described. The preferred siloxanes contain 2 to 5 functional hydroxyl and / or alkoxyl groups. the Choice of the reactants is advantageously so that the siloxane about 10 to about 50 wt .-% of the binder resin obtained in the two-step reaction process

The acrylate used in the first reaction stage provides the olefinic "JS" unsaturation of the resin. Here, as well as below, the α, / 3 position is set to the Carboxyl group of the carboxylic acid based. Suitable acrylates include 2-hydroxyethyl acrylate or methacrylate, 2-hydroxypropyl acrylate or methacrylate, 2-hydroxybutyl acrylate or methacrylate, 2-hydroxyoctyl acrylate or methacrylate and similar acrylate compounds.

The relative proportions of acrylate and siloxane are advantageously adjusted so that they are so close as possible results in a product in which only one functional hydroxyl and / or alkoxyl group des Siloxane reactant is reacted with the acrylate molecules. Such a group remains unreacted, so that it can react with the hydroxylated acrylic resin in the second reaction stage. As the preferred Siloxanes contain 2 to 5 functional groups per molecule, the siloxane molecule has the preferred Final product resins bind 1 to 4 acrylate molecules and 1 molecule of the hydroxylated acrylic resin. However, complete control is not expected and therefore the siloxane molecules in the Paint binder solution average about 0.5 to about 1.5 molecules of the acrylic resin reactant bound. Therefore, the proportions of the reactants in the first reaction stage with respect to the total number of functional groups of the siloxane adjusted so that the remaining converted functional groups of the siloxane Hiirnhsrhnittlich about 0.5 to about 1.5 per molecule be. Those molecules that are completely saturated by the acrylate conversion are with the Acrylic-siloxane resin and with vinyl monomers (»polymerizable and can therefore be used in the paint remain. On the other hand, the hydroxyl-containing acrylic acid resin may have a plurality of reactive ones Hydroxyl groups per molecule, advantageously contain 1 to 10, and therefore a number of Siloxane molecules are bound to a molecule of acrylic resin as a reaction participant.

The copolymer with hydroxyl functional groups made from acrylic monomers is produced by copolymerization various acrylic monomers and contains about 02 to about 2, preferably about 0.5 to 1.5, reactive hydroxyl groups per 1000 units of molecular weight. These will be beneficial formed in the copolymer by using as a reactant a monohydroxyacrylate or methacrylate, for example, the monohydroxy ester of a C2 to Ce diol, and acrylic acid or Methacrylic acid, is used. Fall under this

2-hydroxyethyl acrylate or methacrylate
2-hydroxypropyl acrylate or methacrylate,
2-hydroxybutyl acrylate or methacrylate
2-hydroxyoctyl acrylate or methacrylate
and like acrylate esters.

The comonomers are preferably balanced by esters of monohydric Ci to Ce alcohols of acrylic acid or methacrylic acid, for example methyl methacrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate and the like.The comonomers used to produce this resin can also contain smaller proportions of other vinyl monomers in combination with a larger proportion of the above-listed esters of monohydric C) - to Ce alcohols of acrylic acid or methacrylic acid. Such be used in smaller amounts monomers include acrylic acid, methacrylic acid, glycidyl methacrylate GIycidylacrylat and / or Vinylkohlenwassersto ^f fe such. B. styrene, vinyl toluene, «% -Methylstyrene and the like, and / or acrylonitrile, acrylamide, Methacrylsäurenitri! and / or vinyl halides, for example vinyl chloride and / or vinyl carbocylates, for example vinyl acetate. Such resins have average molecular weights in the range from about 1000 to about 25,000, preferably in the range from about 5000 to about 15,000. The resins can also have a <x, j? -Nonsaturation, so that, for example, glycidyl acrylate or glycidyl methacrylate can be included as comonomers, whereupon the prepolymer obtained is then reacted with acrylic acid or methacrylic acid.

It is advantageous to use siloxanes with functional hydroxyl and / or methoxyl groups. As copolymers are favorably those with about 0.5 to about 1.5 hydroxyl groups per 1000 units of des Molecular weight used

The flexibility of the cured one formed from the thus obtained acrylic-siloxane resin Paint film can significantly by varying the molecular weight of the acrylic copolymer and / or the number of acrylic copolymer molecules per siloxane molecule in the acrylic-siloxane resin can be varied.

The thus obtained acrylic-siloxane resin mixed with acrylic or vinyl monomers forms the Paint. The acrylic monomers are

ren from esters of acrylic acid or methacrylic acid with alcohols with 1 to 8 carbon atoms and the Vinyl monomers from mixtures of Ce to Cio vinyl hydrocarbons and esters of acrylic acid or methacrylic acid with Ci to Q alcohols.

In a particularly favorable embodiment the film-forming solution of the paint consists of 35 to 65 parts by weight of the acrylic-siloxane resin and 65 to 35 parts by weight of the monomers.

The invention is particularly advantageous for covering substrates made of wood, glass, metal, polymer solids and wipes made from synthetic or natural fibers.

The paint is in a conventional manner, for example Spraying, roller mounting and the like, on one Base applied and cured thereon with ionizing radiation, preferably with an electron beam with an average energy im Range from about 100,000 to about 500,000, preferably about 150,000 to about 350,000 electron volts

Those in the solution along with the acrylic siloxane resin applied vinyl monomers consist preferably of acrylic monomers, for example methyl methacrylate, Ethyl acrylate butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, those above in connection Hydroxylacrylate listed with resin production and the like, or mixtures of such acrylic monomers and vinyl hydrocarbon monomers, for example Styrenes, and alkylated styrenes, such as vinyl toluene, «-Methylstyrenes, divinylbenzoi and the like. It can the vinyl hydrocarbons also alone as a vinyl monomer component of the paint binder. In connection with the monoacrylates and / or Hydrocarbon monomers can also contain small amounts of di-, tri- or tetrafunctional acrylates be used. Also in connection with acrylates and methacrylates and / or vinyl hydrocarbons can also use smaller amounts of other vinyl monomers, such as acrylonitrile, acrylamide, Methacrylsäurenitrii, vinyl halides, such as vinyl chloride, and vinyl carboxylates, for example vinyl acetate, be used.

In the preparation of the coating compositions according to the invention, the olefinically unsaturated one in the «^ -position can be used Resin ingredients, d. H. the acrylic siloxane resin up to about 80% by weight of the paint binder solution on pigment and particulate! Filler-free basis and up to a value of about 20% by weight. Preferably, the resin makes up about 35 to about 65% by weight of the resin-monomer solution, the Vinyl monomers are about 65 to about 35 weight percent thereof. Of course, others can too «^ -Olefinically unsaturated polymers instead of a smaller proportion of the acrylic-siloxane paint binder resin are used according to the invention.

The abbreviation »Mradu means 1 000 000 rad. The term "rad" means a dose of radiation that the absorption of 100 ergs of energy per gram of absorber, for example coating film, results. the Electron emitting device may consist of a linear electron accelerator used for training of a direct current potential in the range specified above. In such a device the electrons are usually emitted from a heating wire and through a uniform voltage gradient accelerated. The electron beam, which will have about 3.2 mm in diameter at this point can, is then distorted in one direction to form a funnel-shaped beam, and then through a Metal windows, for example made of aluminum, with small amounts of copper alloyed aluminum, magnesium-thorium alloy with a thickness of about 0.0075 cm

The binder is preferably applied to the backing as a continuous film of practically uniform depth applied and cured thereon, preferably to a depth ranging from about 0.25 to about 100 microns in Depending on the substrate and the intended end use of the coated product. the film-forming binder solution should have a sufficiently low viscosity to allow rapid application to the To allow substrate in practically uniform depth and, preferably of a sufficiently high viscosity so that a 0.0025 cm film is held on a vertical surface without dripping. The viscosity of the binder is determined by varying the relative concentrations of the resin component and / or by varying the relative concentrations of the various monomers within the Vinyl monomer component adjusted The binder is preferably practically free of on the substrate non-polymerizable organic solvents and / or diluents applied, though suitable volatile solvents can also be used which are driven off prior to curing will.

example 1

A hydroxyl-containing copolymer of acrylic monomers, hereinafter referred to as Resin I, was prepared by copolymerization of a mixture of monomers, the composition of which is 40 Mol% methyl methacrylate 50 mol% ethyl acrylate and Was 10 mole percent hydroxyethyl acrylate. The copolymerization was carried out by adding the monomers dropwise together with 1.5% by weight of azobisisobutyroniiril to an equivalent weight of at reflux held xylene reached.

The acrylic-siloxane resin was made from the following materials in the following manner manufactured:

I. Implementation of stage I

The siloxane-acrylate reaction product was obtained from the following materials:

Respondents

Parts by weight

Siloxane with functional
Methoxyl groups')
Hydroxyethyl acrylate

250
80

') Acyclic polysiloxane with an average molecular weight in the range from 700 to 800 with an average of 3 to 4 functional methoxyl groups per molecule.

procedure

The two reactants were heated to 100 ° C heated and the temperature to 150 ° C over a period of 2 hours in the presence of 0.5 part by weight Tetraisopropyl titanate (catalyst) and 0.2 parts by weight of hydroquinone increased. About 21 parts by weight Methanol was distilled off.

H. Implementation of stage 11

The siloxane-acrylate reaction product according to I was reacted with the resin I.

Respondents

Parts by weight

Resin I (50% in xylene)
Siloxane acrylate according to I.

202
93

procedure

The two ingredients were mixed and heated to 100 ° C and increasing the temperature to 130 ⁰ C for 1 hour. Xylene and further volatile reaction products were then removed by vacuum distillation (10 mm Hg at 110 ^° C.).

The acrylic siloxane resin prepared in the above manner was dissolved in 200 parts by weight of methyl methacrylate. A film of this solution was on a Sheet steel drawn up and with an energy of 8 Mrad with an electron beam of 275 kilovolts and irradiated 25 milliamps in a nitrogen atmosphere. The film was HB pencil hardness, held 10 Rubs off with a sponge soaked in methyl ethyl ketone and had good adhesion to the Metal.

Example 2

An acrylic-siloxane resin was made according to the procedure produced according to Example 1 with the difference that functionally equivalent amounts of different Acrylic resins and functional cyclic hydroxylsiloxanes instead of the acrylic resins used in Example 1 and Siloxane was used.

The acrylic resin used here was made by copolymerization of 80 mol% ethyl acrylate 10 mol% Hydroxyethyl acrylate and 10 mol% glycidyl methacrylate manufactured. The copolymerization was carried out by adding the monomers dropwise along with 1.5 wt% azobisisobutyronitrile to the equivalent Weight of refluxed xylene causes. After completion of the reaction, acrylic acid became in one Equimolar ratio to the glycidyl methacrylate added and reacted with the resin.

The siloxane used consisted of a commercially available hydroxyl-functional cyclic polysiloxane with the following properties:

Hydroxyl content according to 5.5 Dean Stark 03 % condensable 1600 % free 400 Average molecular weight 1331 Connection weight 1.539 Refractive index Softening point according to D u r r a n 93 Mercury decay, at 1.075 60% solids in xylene Specific weight at 25 ° C 33 Viscosity at 25 ° C A-I (Centipoise) Gardner-Holdt

Example 3

The procedure of Example 1 was repeated, but using the hydroxylacrylate in the first stage 2-Hydroxyäthylmethacrylat used

Example 4

The process of Example 1 was repeated, but as the hydroxy acrylate used in the first stage 2-Hydroxybutyl acrylate used.

Example 5

The procedure of Example 1 was repeated, but using the hydroxylacrylate in the first stage 2-Hydroxybutyl methacrylate used and an average depth of the applied and cured film of about 0.5 μ applied.

Example 6

The process according to Example 1 was repeated, but as the hydroxy acrylate in the first stage 2-Hydroxyoctyl acrylate used and as the average depth of the applied and cured film about 100 μ applied

Example 7

The process according to Example 1 was repeated, but using the hydroxy acrylate in the first reaction stage 2-Hydroxyoctyl methacrylate used.

Examples 2 to 7 also gave excellent results.

Example 8

The process of Example 1 was repeated, but the paint binder solution contained 80 parts by weight of the acrylic-siloxane resin and 20 parts by weight of methyl methacrylate the base consisted of glass and the Cure was effected by exposure to an electron beam at 295 kilovolts and 25 milliamps

B e i s ρ i e 1 9

The procedure of Example 1 was repeated, but the paint binder solution contained 20 parts by weight an equimolar mixture of methyl methacrylate, styrene, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate the base was made of wood and the hardening was achieved by exposure to an electron beam of Causes 325 kilovolts and 25 milliamps

-

Example 10

The process according to Example 1 was repeated, but the paint binder solution contained 35 parts by weight of the acrylic-siloxane resin and 65 parts by weight of a mixture of 2 molar proportions of methyl methacrylate, a molar proportion of ethyl acrylate / 2 molar proportion of vinyltuluene, ^ molar proportion of divinylbenzene, V2tnolaren proportion of vinyl acetate and V ₂ molar proportion of butyl methacrylate and as a backing, a polymeric solid, namely, an acrylonitrile-butadiene-styrene copolymer used

ίο

while the pad is made of a cotton cloth

Example 11 passed.

Example 12

The procedure of Example 1 was repeated. The procedure according to Example 1 was repeated,

However, the monomer component consisted of a 5 but the paint binder solution was particle-promoting

Mixture of 4 molar proportions of methyl methacrylate, moderate titanium dioxide pigmented,

! molar portion of vinyl acetate, 1/2 molar portion of 2-Hy- Also in Examples 8 to 12 were distinguished

droxyäthylacrylat and 1/2 molar portion of vinyl chloride, good results obtained.

Claims (1)

Claims; X. Coating composition curable by ionizing radiation based on acrylic-siloxane resin and unsaturated monomers, characterized in that it consists of a film-forming solution