DK142449B - Process for making decorative coatings and / or protective coatings on a suction-resistant substrate. - Google Patents

Description

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(11) PRESENTATION

DENMARK ...... .. CQ9D 7 / u § (21) Application No. 5508/71 (22) Filed on 29 · Oct. 1971 (24) Race day 29 · Oct · 1 971 (44) The application presented and the petition published on 5 · HOV. 1 980 DIRECTORATE FOR ......

PATENT AND TRADE MARKET (30) Priority requested from it

Oct. 50 1970, 9779/70, AT

(71) ETERNIT WORKS LUDWIG HATSCHEK, 4840 Voecklabruck, AT: UCB S.A., Saint-Uilles-lez-Brussels, 4, chauesee de Charleroi, BE.

(72) Inventor: Emil Proksch, 1100 Vienna, Laaerbergstr. 58 /? /? 4, AT: Helmut Eschweiler, 110ϋ Vienna, Remystr. 16, AT.

(74) Plenipotentiary in the proceedings:

The engineering company Budde, Schou & Co.

(54) Procedure for the manufacture of decorative coatings and / or to protect tels as well as trash on a sugary substrate.

It has long been known and customary to make paints or other coatings for decorative and / or protective purposes on the most diverse substrates from aqueous dispersions of artificial resins. For this, very finely divided aqueous dispersions of thermoplastic or elastomeric saturated resins are applied to the article to be coated, and the water present in the dispersion is removed by evaporation, suction in the substrate or both, at which time the closely resinous artificial resin particles can form a continuous films.

For this film formation, some plasticity of the resin is needed.

This plasticity can be characterized either by the hardness of the synthetic resin material or better by the minimum film forming temperature (MFT), which is the minimum temperature needed to form a coherent homogeneous film from the separated resin particles. This temperature can be measured e.g. by the method of Protzman, Th. and G. Brown: J. appl. Polymer Sci. £ (1960) p. 81. A further characteristic size is the glass transformation temperature T, which is the temperature above which the y polymer molecule achieves some free movement. It responds approx. to the temperature at which the polymer becomes soft (softening point) and, in addition to other methods, can be measured e.g. by the thermomechanical penetration method. In this method, T is deduced from the rate of penetration of a calibrated sensor placed on the film under constant load into the linearly coated coating film at 5 ° C / minute. Between T and MFT, in the first approximation, a linear relationship exists.

Artificial resin dispersions, which should already form a well coherent film (MFT <room temperature) at room temperature, must necessarily consist of very soft, plastic material and therefore also result in soft, low solid coatings with low glass transformation temperature. If the dispersion is made up of a harder synthetic resin (high MFT and high T), it is necessary to heat the dispersion applied to the substrate to a higher temperature to soften it over the MFT and thus enable a film formation. After cooling, there is then a good coherent, yet tough film.

In many cases, however, the temperatures required for this are too high for practical use, especially in the case of thermally poorly plasticized resins only and / or heat-sensitive substrates. Because of the great advantages of dispersions such as paint or coating medium [e.g. high solids content (about 50%) and high molecular weight for the synthetic resin (from about 10 to about 10), yet with low viscosity of the total dispersion, therefore easy and well reproducible application to the substrate; good storage capacity; low fire risk; however, no release of solvent vapors through the freshly applied coating layer] is desirable to make the use of dispersions possible in these cases as well. The film formation temperature MFT can now also be influenced by other parameters at constant hardness (constant T) of the dispersed artificial resin. The diameter of the dispersed particles, the nature and amount of the surfactants used, as well as the nature of the substrate have little influence; However, the MFT can be substantially reduced by the addition of so-called waxing agents. These agents exert a somewhat dissolving or swelling effect on the artificial resin, thereby reducing MFT and T 2.

A large number of organic solvents have been proposed in the literature for this purpose. However, solubilization by the addition of solvents cannot be considered a satisfactory solution to the problem, as some of the essential advantages of using aqueous dispersions are lost here. The solvents added so far must again be removed after filming in order to: finally obtain a hard film, and for this either have to wait for a very long de-aeration time (while the film is still soft and not adhesive-free) or at least re-applied heat. In addition, the loss of weight during evaporation leads to disturbances in the uniform film structure, to financial losses and to the occurrence of disruptive solvent vapors.

This thus applies to the technique described in DK Patent Application No. 3566/69, according to which a plastic film, ie. a non-absorbent substrate is applied to an aqueous copolymer dispersion, to which is added a saturated swelling or solvent, after which the coating is dried. This is a time-consuming and labor-intensive process because the substrate's lack of absorbency means that it cannot assist in faster drying.

It has also been attempted to apply coatings to a substrate by simultaneously spraying a plastic dispersion in an organic carrier liquid (an organosol) and a solvent which may be formed by a monomer, and to cure on the substrate, cf. GB Patent No. 930,919.

A disadvantage of this method is that, on the one hand, technically complicated apparatus for the simultaneous spraying of organosol and solvent is necessary, a roller or brush application is therefore excluded, and on the other hand considerable variations in the amount ratios between the two components, which lead to irregularities in the properties of the finished coating, are not neglected in this process. Furthermore, very little time is available for the necessary swelling of the artificial resin grains by means of the solvent.

Another disadvantage of this method is that it is not possible to make an optimal adaptation to the requirements at all times by selecting storage times or temperatures because spraying, mixing and application is done in a single process step. This means that in order to achieve the desired properties it is necessary to "store" the freshly-sprayed resin on the substrate in a "moist" state, ie. a condition in which the coating is highly susceptible, e.g. by touch or exposure to dust.

There is further described a process for the preparation of overcoat according to which an unsaturated synthetic resin is mixed with a monomer and a suspension made from these two components is applied to metal by an electric field and polymerized on the metal, cf. DT Publication No. 1,621,911. The scope of this method is limited to special resin types with a certain number of double bonds and acidic groups in the polymer molecule, which results in a correspondingly expensive and also complicated production. In addition, the substrates are limited to electrically conductive media, and also technically expensive apparatus is required for the coating application.

Finally, from DT Publication No. 2,003,819, a method for coating sugary substrates is known, but the prior art is however limited to coating with solutions of polyvinyl chloride (PVC) in monomers, although also the possibility of coating with "dispersions" of PVC in plasticizers is featured.

A disadvantage of this known method is that if one wishes to apply PVC by e.g. ironing, immersion or spraying must use relatively large quantities of monomers (plasticizers). Apart from the increased costs of this, it must also be assumed that the individual PVC grains are dissolved ("dispersed") to such a degree that there is a risk that they can be absorbed by the substrate. This in turn leads to disjointed, perhaps even deficient, coatings. In order to remedy this, more than one application is required according to the above-mentioned DT publication, which requires both time and work.

It is the object of the present invention to provide a method which does not exhibit the disadvantages and in which, while preserving the advantages shown by the use of aqueous dispersion, uniform uniform coatings and / or protective coatings of high quality are ensured. quality also using simple methods of application.

Accordingly, the present invention provides a process for making decorative and / or: protective coatings on a sugary substrate, wherein a method of dispersing an artificial resin, optionally added pigments, finely divided fillers and / or other additives, is applied to that substrate. , which is to be coated, together with a polymerizable organic liquid, and cured on the substrate by polymerization, and the process of this invention is characterized in that an aqueous dispersion of a saturated resin is mixed with the polymerizable organic liquid to swell the resin particles. , the aqueous dispersion thus obtained is then applied to the substrate made of wood, wood construction materials, cardboard, paper, textile fabrics, concrete, fiber cement or natural stone and finally cured.

Through the addition of the liquid monomer to the aqueous resin dispersion even before application, the desired resin composition is achieved. The stirred liquid first forms its own phase separated from the resin in the form of small, water-dispersed droplets. This state then - depending on the condition more or less rapidly - switches to more stable conditions in which the liquid is absorbed by the artificial resin bodies, and these first swell only on the surface, then also in the interior.

While the swollen state is in principle peculiar to the fact that at least the surface of the resin grains is swollen, without causing a substantial change in the properties of the dispersion, and thus becomes soft or even sticky, it occurs in the case of a separate phase of the added liquid at the latest after the evaporation or suction of the water present in the applied dispersion layer to an intimate contact between the resin grains and the liquid and to a surface coagulation of the former. If, after application, a coherent film of the synthetic resin grains has formed, the waxing can be reduced by transferring the added liquid in the polymer to solid form, thereby producing a well-cured film. This can be done both by either polymerizing the liquid used individually and by its grafting copolymerization on the polymer resin polymer skeleton used or through both processes simultaneously.

Such a method not only achieves the objective of obtaining impeccable films of aqueous dispersions of harder saturated resins on heat sensitive substrates, but it is also possible in this way to produce decorative coatings and / or protective coatings with novel other ways not attainable properties. By varying the manufacturing conditions, especially of the starting materials, coatings of the most different chemical composition and most different microscopic structure can be obtained; The properties are also variable within wide limits. The inherent advantages of the aqueous dispersions are largely retained by this. The processability of the dispersions usually does not change or only slightly because of the monomer addition. The durability of the aqueous dispersions that have been added to monomers is not uniform. It may, as has been surprisingly noted, be extended to periods of many months and beyond; In cases where the storage capacity is only short, the liquid can best be added to the dispersion only shortly before processing. The fire risk of monomers added to dispersions is only slightly greater than that of conventional resin dispersions.

Since the added liquid, after application of the dispersion on the substrate, does not evaporate again as a solvent, but is incorporated into the coating, the problem of nuisance in the event of any flammable and / or toxic fumes is also low. The process of the invention for the manufacture of decorative coatings and / or protective coatings therefore constitutes a novel process principle of great practical importance.

A further important advantage of the invention is that the obtained film surfaces also become hard and adhesive in the presence of air. It is known that the oxygen of the air exhibits an inhibitory effect in radical polymerization reactions. Therefore, in coating films made by polymerizing applied polymerizable or copolymerizable solutions, the surface must be protected from the oxygen of the air. Such protection is obtained e.g. by curing under an inert oxygen-free protective gas, or by covering the surface with an oxygen-impermeable paraffin layer such as e.g. is usual in the polymerization of styrene-dissolved unsaturated polyester resins. Surprisingly, the process according to the invention showed only a small oxygen influence on the rate of polymerization, and the surfaces obtained are also adherent to air curing. Apparently, the influence of oxygen on the polymerization of the liquid portion no longer affects the macroscopic properties of the finished film surface on U 2449 7 due to the presence of the high excess high molecular weight starting resin.

As a starting point for the process, aqueous dispersions of any saturated resins may be mentioned. By the term "saturated" it is to be understood that the synthetic resins in question do not contain any intentionally polymerizable or copolymerizable double bonds, as is the case, for example. by the unsaturated polyester resins or by the electron beam curable unsaturated acrylic resins. The presence of minor traces of olefinic double bonds arising from contamination · 1, side reactions in the manufacture or by disproportionation reaction in a bimolecular chain break · of the polymerization reaction used in the manufacture is not excluded here, nor is the other chemical resin however, it is preferred that the aqueous dispersion of a polyvinyl chloride resin (vinyl chloride homopolymerate, vinyl chloride / vinyl acetate) be used as an aqueous dispersion of a particular chemical or structural structure. merisates and other copolymers of vinyl chloride), acrylic resin (polymerisates and copolymers of various acrylic or methacrylic compounds), polystyrene resin (polymerisates and copolymers of styrene, for example with butadiene or acrylic acid), an aqueous polyurethane dispersion, an aqueous polyurethane dispersion, dispersion or a mixture of two or more of said aqueous dispersions. The mixture is further processed after the addition of a liquid which causes both resins to grow together. These dispersions have the additional advantage that, regardless of the nature of the polymerizable liquid used, rapid and uniform swelling of the resins is achieved and, on the other hand, high strengths (impact and tear strengths) can be obtained. the out-polymerized coating.

Of course, the aqueous resin dispersions used can, before or after the addition of the polymerizable organic liquid, be added to the usual additives such as, for example, a fully compounded coating. pigments and fine-grained fillers, in addition to the synthetic resin acting as a binder. These additives are also referred to the additives for which it is known that they change the properties of the coating film in a characteristic manner, e.g. silicones which make the film surface water-resistant (eg, according to Belgian Patent No. 542,765). The effect of such additives is also retained by the process of the invention.

As a polymerizable organic liquid, any liquid which can be brought to polymerization or to graft copolymerization on the synthetic resin in the dispersion used, by simple and gentle methods without the use of extreme reaction conditions.

It is preferred according to the invention that as a polymerizable organic liquid, a liquid consisting predominantly of the additives needed for the polymerization, e.g. initiators, accelerators, regulators and UV sensitizers, as well as a vinylic, allylic or maleically unsaturated organic compound or a mixture of such compounds, i. vinyl compounds (including the vinylidene and acrylic compounds) characterized by a terminated olefinic double bond: = ch 2 e.g. vinyl acetate, vinylidene chloride, vinyl sulfoic acid, acrylic acid, acrylonitrile, acrylic and methacrylic acid esters, styrene and vinyl carbazole, allyl compounds characterized by the grouping ^ CH-CH = CH2 e.g. the esters and ethers of allyl alcohol, or maleically unsaturated compounds characterized by the grouping -CO-CH = CH-CO - e.g. maleic acid and its derivatives. These compounds have the additional advantage that, although the resin selected does not completely match the chemical structure of the unsaturated compound which serves to swell, it readily penetrates the resin and provides the resin particles present in the dispersion which are swollen with the polymerizable liquid, the property of penetrating a small distance into the pores of the substrate, thereby obtaining a good anchoring of the cured coating.

From this, a large number of combination options can be deduced. Limited, the number of possible combinations between synthetic resin and polymerizable organic liquid is only required by the liquid to swell the synthetic resin sufficiently strongly. This is usually at least (but not only then) when the liquid consists predominantly or in large part of a compound or mixture of compounds having the same or similar chemical structure (other than the double bond) as the synthetic resin . Thus, e.g. advantageously very styrene-containing liquid mixtures for polystyrene dispersions, and advantageously predominantly acrylic and methacrylic acid esters consisting of acrylic resins. But also, due to the lack of structural similarity between synthetic resin and added liquid, there are numerous combinations that meet the above requirement.

The required amount of the polymerizable organic liquid to be added can also be varied within wide limits. It, on the one hand, adjusts to the size of the desired or necessary coagulation effect - the more the film-forming temperature of the aqueous resin dispersion used must be 1 or must be lowered, the more liquid it must be added - on the other hand also the solubility of the liquid in the artificial resin and its properties. emerging solid or semi-solid solution. It has been found particularly convenient according to the invention that the amount of the polymerizable organic liquid to the aqueous resin dispersible organic liquid for every 100 parts by weight of the synthetic resin contained in the dispersion is 1-100, preferably 2-30 parts by weight, since both very good film forming properties are obtained. of the artificial resin and an optimal hardness of the finished coating. In the case of poorer additions, the effect obtained is usually no longer noticeable; for too high additions, the individual synthetic resin grains become small droplets of liquid and the system loses the characteristic properties of a dispersion of solid particles.

In order to accelerate the transition of the artificial resin dispersion system with added liquid to the stable final state already described, namely the complete absorption of liquid by the artificial resin grains and the uniform distribution thereof, it is appropriate to stir intensely at the liquid addition and, optionally, to raise the temperature. This is why, according to the invention, it is preferred that the polymerizable liquid be admixed with the aqueous resin dispersion at a temperature located between room temperature and boiling beginning of the liquid used. Furthermore, it is hereby achieved that the amount of polymerizable liquid in the resin can be lowered without compromising the swelling degree of the resin.

The attainment of the final state is also promoted by the fact that the liquid addition does not take place immediately prior to the application of the dispersion but already at an earlier time, which is why a particular embodiment of the process according to the invention is peculiar to the time of mixing. up to 6 months prior to the use of the mixture, that the mixture which has been added liquid is kept for a total storage period or during parts thereof at an ambient temperature between the room temperature and the beginning of the cooking. This embodiment is of particular importance in polymerizable liquids which cannot withstand elevated temperature for a long time, since it ensures that even in such liquids a very uniform distribution of the liquid in the resin particles can be achieved.

On the other hand, it is endeavored to achieve certain properties and to minimize the amount of fluid required, e.g. in the case of a relatively expensive liquid, not to distribute the polymerizable organic liquid evenly over the entire cross-section of the resin grains, but rather to concentrate it on the surface, it is preferred that the polymerizable organic liquid be mixed with the resin dispersion immediately prior to application of the dispersion on the substrate at a temperature between 0 ° C and room temperature. In this case, the formation of the coating can be said to be a kind of "sintering" of the resin particles.

Thus, the process according to the invention has an extremely wide adaptability both to the given apartment and to the properties of the starting materials as well as to the requirements of the final products. If one fails to separate the admixture of the polymerizable organic liquid from the application to the substrate to be coated, i.e. to spray the aqueous dispersion and the polymerizable organic liquid simultaneously in one operation, this adaptability is completely lost. In addition, the simultaneous application of two components, as already mentioned, can be difficult to realize in technical and temporal proportional quantities, over time and locally (over extended surfaces of thin layer thicknesses).

As far as possible - by known methods (eg, ironing, pouring, spraying) - applying the aqueous dispersion which has been added to the liquid, the water contained in the applied thin layer is removed by suction into the substrate and / or by evaporation. Already during this process and, of course, especially in the subsequent period until 142449

II

After complete curing, there is the possibility that some of the added polymerizable organic liquid also evaporates. However, unlike water, the organic compounds are not present as their own phase but are dissolved in the synthetic resin, and therefore, even at the boiling point determined by the water, have a substantially lower vapor pressure and a lower evaporation rate than non-dissolved monomer. Therefore, the dispersion layer applied to the substrate is rapidly dewatered (eg in the presence of a good absorbent substrate) and then cured immediately by a rapid and non-heating method (eg by irradiation with UV light or with energy rich radiation), the amount of evaporating organic liquid even using relatively low boiling monomers (such as, for example, vinyl acetate or acrylonitrile) is very small and not disruptive. However, if cured slowly and at elevated temperature, the evaporation losses are naturally higher. In order to fully achieve the advantages of the method in this case, which involves a reduction of the evaporation vapors, especially on non-suction substrates, at high radiation doses, at high curing temperature and / or long irradiation time, it is preferred according to the invention that the polymerizable organic liquid contains at least 30% higher boiling, heavy volatiles, such as e.g. hydroxyalkyl acrylates, hydroxyalkyl methacrylates, acrylic or methacrylic acid esters of glycols and other polyalcohols or allylic esters of polyacids.

Topical as absorbent substrates are a whole variety of organic and inorganic substrates, such as e.g. wood, plywood, particle board, fiberboard, cardboard, paper, textile fabrics, concrete, fiber cement and natural stone.

The final step of the described process, namely the polymerization or graft copolymerization of the added organic liquid, can be carried out by various already known methods. Thus, for example, a thermal-catalytic cure is possible, whereby the polymerizable organic liquid is added to its initiator (e.g., peroxide, azo compound or redox system) prior to its addition to the synthetic resin dispersion and the subsequent cure is triggered. by thermal decomposition of this initiator. This method is, among other methods tested here, simple and universally applicable. In doing so, it must be borne in mind that the storage capacity of the dispersion which has been added with liquid decreases due to the initiator addition, that liquid mixing and storage do not can be carried out at elevated temperature and that very temperature sensitive substrates cannot be treated by this method, since heating of the substrate also by heating the dispersion layer to the initiator temperature of activation can hardly be avoided.

When applied to temperature-sensitive substrates, it is an advantage of the invention that the polymerization or graft copolymerization of the added polymerizable organic liquid take place through the action of irradiation with ultraviolet light. This has the advantage that the curing takes place very quickly, in seconds or even fractions thereof, and that a heating of the coating and thus an evaporation of the polymerizable liquid is avoided. However, when cured with UV light, the addition of a UV sensitizer is necessary. Known UV sensitizers which may be used in the context of the present invention are: benzoin, benzophenone, anthraquinone and derivatives thereof; aromatic disulfides; O-alkylxanthates, bis-xanthogen disulfides, α-halogen ketones, haloacetic acid and sulfonyl chlorides. However, the UV-induced curing is limited to coatings whose absorption in the wavelength range used is not so strong that the lower regions of the applied layer are no longer sufficiently irradiated. Only UV-permeable additives such as e.g. CaSO4, SiC2 and talc. For the same reason, the possible layer thicknesses are also limited.

In the case of irradiation with energy-rich radiation, these limitations lapse. Here, too, the curing takes place very quickly in seconds or fractions thereof. No sensitizer needs to be added, the polymerizable liquid can even be used in the inhibited state, whereby the storage capacity of the system can be increased practically indefinitely, and all restrictions on temperature degrade liquid to the setting and subsequent storage fails; Highly pigmented coatings or coatings with high fillers content can also be cured, even in larger layer thicknesses. In fact, it is possible to cure, without heating, coatings of any thickness and with any practically applicable composition of the constituents, resin and polymerizable liquid contained therein in a gentle manner, yet with deep penetration into the coating without the radiation therefore down to the substrate, resulting in an increased coating life. It has been found, according to the invention, that these advantages are particularly achieved by the polymerization or grafting copolymerization of the added polymerizable organic liquid by the action of energy-rich radiation, especially by the action of electrons having an average energy of 50-500 keV, air, optionally under protective gas or in vacuum.

The polymerization of the organic liquid present in the dissolved granules in liquid form is substantially favored over the polymerization of the pure liquid, namely by the effect of the gel effect. The high viscosity of the system leads to sharp increases in polymerization rates irrespective of thermally-catalytic curing or irradiation. In addition to the polymerization of the added liquid alone, which ultimately leads to a mixture of the initially present resin with a newly emerged, it also results in graft copolymerization of the liquid on the polymer backbone of the synthetic resin used, i.e. for chemical bonding between old and new resin. While the graft copolymerization plays only a minor role in the thermal-catalytic cure and in the UV radiation cure, as it can only be accomplished by occasional chain transfers, it is the predominant reaction in the electron beam cure. Here, the chain-starting radicals are predominantly formed in the polymer chain of the starting art resin, and the monomer units in the added organic liquid are seeded at these radical sites. In addition, electron-curing also results in non-grafting polymerization of the added liquid.

In the following, the nature of the invention is further elucidated by way of examples.

Example 1.

An aqueous dispersion of a methyl methacrylate / ethyl acrylate copolymer (weight ratio of the two copolymerization components 50:50) having a solids content of 40 weight percent is mixed with 5 weight percent ethylene glycol dimethacrylate (EGDMA). The resulting mixture is completely stable; its storage capacity is the same as the storage capacity of the dispersion used as a starting material.

The mixture thus prepared is sprayed up to an application of 155 g / m 2 (measured in the moist state) on a 6 mm thick ash plywood (13 x 40 cm). This application may take place at any time after the admixture of the ethylene glycol dimeth acrylate. After 1 minute, the water is absorbed by the wood substrate and at room temperature forms an impeccably coherent, uniform but soft coating film with a pencil hardness of 2B. Then the sample is irradiated in air at a dose of 4 Mrad of fast electrons (I.C.T. electron accelerator, 500 keV, 20 mA, throughput speed 30 m / minute). An impeccably hard film with a pencil hardness of 4H is available.

14

Example 2 142449

The same dispersion as in Example 1 is mixed with 5% by weight ethylene glycol dimethacrylate and 0.1% benzoin methyl ether. This mixture is as stable and durable as that of Example 1.

2

The mixture is applied until an application of 49 g / m (measured in the moist state) to another model of the substrate used in Example 1. After 1 minute, the sample is irradiated for 5 minutes at a distance of 10 cm with a 1000 W HTQ-4 ultraviolet lamp (Philips). An open film with an open pore structure is available, which after light sanding gives a decorative finish.

Comparative Example 1

The same dispersion as in Example 1 is added 5% by weight of ethylene glycol dimethacrylate, poured onto a flat glass plate and subjected to a flow of air at a temperature of 25 ° C for 10 minutes. This creates a uniform but soft coating film. This film is then irradiated as described in Example 1 at a dose of 4 Mrad of fast electrons. Small pieces of the coating film are detached before and after the electron irradiation from the substrate, and herein the glass transformation temperatures are determined by the thermomechanical penetration method. While the coating film before irradiation has one of 14 ° C, after the electron irradiation a T of 52 ° C is found.

In a comparison experiment without the addition of ethylene glycol dimethacrylate, the air flow temperature must be raised to 50 ° C to obtain a coherent film. The glass transformation temperature is 45 ° C both before and after the electron irradiation.

Comparative Example 2

Comparative Example 1 is repeated, however, with the addition of 0.1% by weight of benzoin butyl ether and with the replacement of the electron radiation with various long irradiations with the UV lamp described in Example 2. The films prepared without the addition of ethylene glycol dimethacrylate, for irradiation times of 0-10 minutes, all give a constant T ^ of 45 ° C. The samples prepared with the addition of ethylene glycol dimethacrylate give irradiation times of 0, 1, 2, 3, 5, 7 and 10 minutes = values of 14, 15, 19, 26,. 49, 51 and 52 ° C.

142449 15

Comparative Examples 3-5

A commercially available aqueous dispersion of a copolymer of methyl methacrylate, ethyl acrylate, acrylonitrile and acrylic acid having a 40% solids content, a film forming temperature MFT of 64 ° C and a Tg of 70 ° C is poured without further addition (Comparative Example 3). after the addition of 6.7% by weight of the conventional plasticizer butylglycol acetate (BGA) (Comparative Example 4) or after the simultaneous addition of 6.7% by weight of ethylene glycol dimethacrylate and 0.08% by weight of benzoyl peroxide (BP) (Comparative Example 5) on glass plates present in a hot air stream. The heating of this air stream is done to a temperature that. is 5 ° C above the film formation temperature MFT of the mixture. On the coating films thus formed, the glass transformation temperatures are determined as described in Comparative Example 1. Thereafter, the samples are heated for 2 minutes in a hot air stream to 140 ° C and the resulting weight loss of the film as well as the glass conversion temperatures Τ The results are summarized in Table I.

Table I

Compare- "

recovery MFT g After 2 minutes at 140 ° C

Example Addition (° C) (° C) Weight Loss T 2 (° C) 3 None 64 70 None 70 4 6.7% butyl ', glycol acetate 28 53 15% 68 5 6.7% ethylene glycol dimethacrylate + 0.08% benzoyl peroxide 42 42% 75

Example 3

The aqueous dispersion used in Comparative Examples 3-5 is added 6.7% by weight ethylene glycol dimethacrylate and 0.08% by weight benzoyl peroxide and sprayed onto a 5 mm thick sheet of fiber-2 cement until an application of 85 g / m (measured in a moist state) . With the action of an air flow of 45 ° C, a continuous coating film is formed. Then the sample is heated in a hot air stream for 2 minutes to U2449 16 140 ° C. An impeccably hard coating film is available.

Example 4

The dispersion described in Example 1 is stirred with 6% by weight of a mixture of n-butyl methacrylate (BuMA.) And ethylene glycol dimethacrylate (1: 2 weight ratio). The resulting mixture is completely stable and durable. After 1 week, the mixture thus prepared is sprayed onto a 5 mm thick sheet of fiber cement 2 (10 x 15 cm) until an application of approx. 75 g / m (measured in moist state). After a deaeration time of 2 minutes at room temperature, the sample is irradiated in air at a dose of 4 Mrad of fast electrons (accelerator voltage 300 keV, beam current 10 mA, throughput 25 m / minute). An impeccable, good adhesive and scratch-free coating is available. Coated hardness is determined by the shaft hardness method according to Konig (DIN No. 53.157) and is 103 seconds.

In a comparison experiment without the addition of the polymerizable liquid, no coherent film is obtained. In another comparison experiment without the addition of the polymerizable liquid, the applied film and substrate are heated to 60 ° C. An impeccable movie is available, however, whose hardness is only 70 seconds.

Example 5

Example 4 is repeated, however, using as a polymerizable liquid a mixture of methyl acrylate (MA.) And butylene glycol dimethacrylate (BuGDMA) in the weight ratio of 1: 2 instead of the n-butyl methacrylate / ethylene-glycol dimethacrylate mixture. An impeccable, good adhesive and scratch-free coating is available with a shelf hardness of 95 seconds.

Example 6 97.8 parts by weight of the dispersion described in Example 1 is stirred with 12.2 parts by weight of a mixture of n-butyl methacrylate / ethylene glycol dimethacrylate (1: 2 weight ratio). The resulting mixture is completely stable and durable. After 1 week, this mixture is mixed with 60 parts of an aqueous dispersion of a poly (methylphenylsiloxane) resin having a solids content of 15% by weight, and then the mixture thus prepared as described in Example 4 is applied and irradiated. An impeccable, smooth, well-adhesive and scratch-free coating is available with a pendulum hardness of 94 seconds.

Example 7

Example 6 is repeated, however, as a polymerizable liquid, a mixture of methacrylate and butylene glycol dimethacrylate is used in a weight ratio of 1: 2 instead of the n-butyl methacrylate / ethylene glycol dimethacrylate mixture. An impeccable, smooth, well-adhesive and scratch-free coating is available with a pendulum hardness of 89 seconds.

Example 8

Example 6 is repeated, however, 10% by weight of carbon tetrachloride is added to the n-butyl methacrylate / ethylene glycol dimethacrylate mixture and the fiber cement backing is enlarged to 120 x 54 cm. The*? an impeccable, well-adhesive, smooth and scratch-free coating is available with a pendulum hardness of 94 seconds. The sample is then divided and further tests are performed on the parts. The samples show no disadvantage both after boiling test (24 hours in boiling water) and after frost testing according to ONORM No. B 3422 (25 frost thaw cycles every 3 hours at -20 ° C and 1 hour at + 20 ° C in water). change.

Example 9

An aqueous dispersion of a copolymer of methyl methacrylate ethyl acrylate, acrylonitrile and acrylic acid (73: 15: 10: 2 weight ratio) with a solids content of 36 weight percent is stirred with 13 weight percent of a mixture of methyl acrylate and butyl glycol dimethacrylate (weight ratio 1). : 2). The resulting mixture is completely stable and durable. After 1 week, it is applied as described in Example 4 and irradiated. An impeccable, well-adhesive and scratch-free tread with a pendulum hardness of 127 seconds is available.

In comparative experiments without the addition of the polyxerizable liquid, no coherent and adhesive film can be obtained even by heating the applied film and the substrate to temperatures up to 150 ° C.

Comparative Example 6

By means of this example, the wax-promoting effect of the added polymerizable liquid is illustrated.

The dispersion described in Example 1 is mixed with intensive stirring with 7% by weight methyl methacrylate, to which has been added 0.2% by weight "Macrolexgrun GG" (Bayer) for better visibility. This mixture is centrifuged for 4.5 hours in an ultra-centrifuge at an acceleration of 85,000 times the acceleration of gravity. Thereafter, the dispersion is separated into only two phases, namely in a colorless water layer above and a strong green-colored, rubbery soft precipitate. Since methyl methacrylate is lighter than water, and the present methyl methacrylate had to be separated as a top layer on top of the water in the form of its own phase, it is hereby proved that all methyl methacrylate is in a form bound to the acrylic resin dispersion.

Comparative Example 7

The dispersion described in Example 1 is added 4.8% by weight butylene glycol dimethacrylate and the mixture is sprayed onto a 200 thick polyethylene film. After drying in an air stream, a coherent uniform film is obtained with a layer thickness of 50 µ. A 5 x 4 cm piece of the coated polyethylene film is cut, clamped into a frame and reproducibly used in an infrared spectrophotometer. After measuring the intensity of the C = C oscillation bands at 1635 cm 2, which measures the amount of butylene glycol dimethacrylate present, the film is again taken out of the spectrophotometer and irradiated as described in Example 1 in air at a dose of 2 Mrad of fast electrons. A hard, adhesive coating film is obtained on the substrate. A new infrared spectroscopic measurement shows that 79% of the initially unsaturation has been used up.

Example 10

An aqueous dispersion (solids content 50% by weight) of a styrene resin obtained by copolymerizing a mixture of 74% by weight styrene, 24% by weight butyl acrylate and 2% by weight acrylic acid has a film forming temperature MFT of 69 ° C. After adding 5% by weight of methyl methacrylate and styrene respectively, the MFT is lowered to 63 and 42 ° C, respectively, which corresponds to better swelling properties of styrene for this resin.

The styrene-containing dispersion is sprayed onto a 5 mm thick sheet of fiber cement. By the action of one to approx. 47 ° C heated air flow forms a homogeneous coating film. The sample is then irradiated as described in Example 1 in air at a dose of 2 Mrad of fast electrons. A hard, firmly adhesive and non-stick coating forms.

Claims (6)

19 1A2A49 Patent Claims. A process for making decorative coatings and / or protective coatings on a sugary substrate, by applying a dispersion of an artificial resin, optionally added pigments, finely divided fillers and / or other additives, to the substrate to be coated. polymerizable organic liquid, and cured on the substrate for polymerization, characterized in that an aqueous dispersion of a saturated synthetic resin is mixed with the polymerizable organic liquid to swell the artificial resin particles, the aqueous dispersion thus obtained is applied to that of wood, wood construction materials, cardboard, paper , textile fabrics, concrete, fiber cement or natural stone consisting of substrates and eventually cured. Process according to claim 1, characterized in that as an aqueous synthetic resin dispersion, an aqueous dispersion of a polyvinyl chloride resin, acrylic resin, polystyrene resin, an aqueous chlorine rubber dispersion, or a mixture of two or more of said aqueous dispersions is used. Process according to claim 1 or 2, characterized in that as a polymerizable organic liquid, a liquid consisting predominantly of the additives needed for the polymerization, e.g. initiators, accelerators, regulators and UV sensitizers, as well as a vinylic, allylic or maleically unsaturated organic compound or a mixture of such compounds. Process according to any one of the preceding claims, characterized in that the amount of polymerizable organic liquid added to the aqueous resin dispersion for every 100 parts by weight of the resin contained in the dispersion is 1-100, preferably 2-30 parts by weight. Process according to any one of the preceding claims, characterized in that the polymerizable liquid is admixed with the aqueous resin dispersion at a temperature located between room temperature and boiling beginning of the liquid used. Process according to any one of the preceding claims, characterized in that the time of the admixture is added up to 6 months before the application of the mixture and the mixture which has been added with liquid, during the total storage time or during parts thereof. is held by a middle living room-