Fluorine-free coating composition

Abstract

The invention relates to the use of a fluorine-free coating composition that contains at least one polycarbodiimide compound, the at least one polycarbodiimide compound having at least two hydrocarbon groups, each containing 4 carbon atoms, for proofing flooring, not including carpets. The invention also relates to a fluorine-free coating composition and to flooring coated with said composition.

Description

[0001] Fluorine-free coating composition

[0002] The invention relates to the use of a fluorine-free coating composition, a fluorine-free coating composition and a floor covering coated with the coating composition.

[0003] Today, floor coverings such as laminate or parquet are usually joined together mechanically rather than with adhesives. Tongue-and-groove constructions have proven effective for this.

[0004] However, these floorings have the problem that water or cleaning chemicals can penetrate the joints. This causes the flooring to swell at the edges. The result is uneven surfaces that are unsightly and create tripping hazards. Furthermore, water can seep through the joints underneath the flooring, causing water to seep into the floor or cause mold growth.

[0005] Therefore, current technology uses oils or waxes as waterproofing agents for floor coverings, which are particularly resistant to water or aqueous solutions. However, these materials do not dry completely, offer only superficial protection, or are not durable. Furthermore, waxes are very difficult to apply. This results in very thick layers, making it impossible to properly bond the individual panels. Furthermore, the materials often contain fluorine, which is harmful to both the environment and users.

[0006] Therefore, there was a desire for a coating for floor coverings, especially for indoor use, that could be applied to the edges of flooring elements or over the entire surface and that offered sufficient protection against water and cleaning chemicals. Furthermore, the coatings had to be fluorine-free for environmental reasons. They should be easy to apply and sufficiently penetrate the floor material.

[0007] This object was achieved by using a fluorine-free coating composition for impregnating floor coverings. This composition contains at least one polycarbodiimide compound a, wherein the at least one polycarbodiimide compound preferably has at least two hydrocarbon groups, each having at least 4 carbon atoms, preferably at least 12 carbon atoms, and more preferably at least 16 carbon atoms.

[0008] The composition used according to the invention is used to increase the water-repellent effect of substrates.

[0009] A "fluorine-free" coating composition herein means that a composition used for impregnation contains less than 1 weight percent (1 wt.%) fluorine in a composition. In certain embodiments, a "fluorine-free" coating composition means that a coating composition preferably contains less than 0.5 wt.%, less than 0.1 wt.%, or less than 0.01 wt.%. The fluorine may be in the form of organic or inorganic fluorine-containing compounds.

[0010] The polycarbodiimide compounds have at least two hydrocarbon groups, each containing at least 4 carbon atoms. In certain embodiments, useful polycarbodiimide compounds are derived from a carbodiimidization reaction (i.e., a reaction in which (N=C=N) groups are formed) of a carbodiimidization reaction mixture containing at least one oligomer, such oligomer containing at least one (typically one) isocyanate end group and at least two repeating units, each of the at least two repeating units having at least one (typically one) hydrocarbon group having at least 4 carbon atoms (and in certain embodiments, up to 60 carbon atoms or up to 30 carbon atoms).

[0011] In one embodiment of the invention, the at least one polycarbodiimide compound is derived from a carbodiimidization reaction of a carbodiimidization reaction mixture comprising at least one oligomer, wherein the oligomer comprises at least one isocyanate end group and at least two repeating units, wherein each of the at least two repeating units comprises at least one hydrocarbon group having at least 4 carbon atoms.In a further embodiment, the polycarbodiimide compound is derived from a carbodiimidization reaction of a carbodiimidization reaction mixture comprising 4,4'-methylenebis(phenyl isocyanate) and an acrylate oligomer in a molar ratio of 2:1 to 10:1, wherein the acrylate oligomer is prepared by reacting an oligomerization reaction mixture comprising mercaptoethanol and octadecyl acrylate in a molar ratio of 1:4 to 1:20, or an oligomerization reaction mixture comprising mercaptoethanol and a reaction product of octadecyl isocyanate with 2-hydroxyethyl (meth)acrylate or octradecyl isocyanate with 2-isocyanatoethyl (meth)acrylate, wherein the mercaptoethanol and the reaction product are reacted in a molar ratio of 1:4 to 1:20.

[0012] Oligomers include compounds having at least 2 and up to 20 repeating units. In a particular embodiment, the oligomer has 3 to 15 repeating units. In another embodiment, the oligomer has 4 to 15 repeating units. In certain embodiments, an oligomer has a weight-average molecular weight of up to 50,000 g / mol.

[0013] It is preferred that the composition comprises at least one paraffin wax b. The paraffin wax preferably has a melting point of 40°C to 75°C. In preferred embodiments, the paraffin wax has a melting point of 60°C to 75°C. The mass ratio of paraffin wax b to polycarbodiimide a is preferably 3:7 to 7:3, preferably 5:5 to 7:3.

[0014] The proportion of polycarbodiimide compound and paraffin wax in the composition is preferably 1 to 20 wt.%, based on the total weight of the composition. Suitable polycarbodiimide compounds and paraffin waxes, as well as their preparation, are described, for example, in US Pat. No. 1,112,4918 B2.

[0015] The coating composition preferably comprises at least one polymer c selected from alkyd resins, acrylate resins, polyurethane-modified polyesters, silanes, siloxanes, or mixtures thereof. The proportion of the polymer is preferably 5 to 40 wt.%, based on the total weight of the composition. The polymers may carry anionic groups, for example, sulfonic acid groups.

[0016] The alkyd resin can be a long- or medium-chain alkyd, for example. Long-oil alkyds are alkyd resins with a fatty acid content of more than 60%; medium-chain alkyds contain 40 to 60% fatty acids. Suitable fatty acids include vegetable fatty acids. The acid number is preferably less than 20 mg KOH / g; the iodine number is preferably less than 20. The alkyd resin can be urethane- or isocyanate-modified or not to promote water resistance. The advantage is threefold: In addition to the price advantage, the alkyd not only provides increased viscosity, but, especially with a medium- or long-chain resin, it penetrates less deeply into the wood and can act as an initial barrier, contributing to its low dispersion. The resin forms an outer film. Since a relatively thin layer is applied, the coating does not require drying to comply with current ecological standards (AgbB, etc.).

[0017] Acrylic resins can include pure acrylates or styrene acrylates. Suitable monomers include methyl methacrylate, styrene, acrylonitrile, butyl methacrylate, ethyl acrylate, butyl acrylate, or ethylhexyl acrylate. Monomers such as methacrylic acid, glycidyl methacrylate, 3-(trimethoxysilyl)propyl methacrylate, acetoacetoxyethyl methacrylate, acrylic acid, itaconic acid, or diacetone acrylamide can also be incorporated. Suitable acrylate resins are offered, for example, by BASF (Germany) under the name Joncryl.

[0018] Polyurethane-modified polyesters are, for example, branched, unsaturated, aromatic, or aliphatic polymers. They have a number-average molecular weight between 1,000 and 20,000 g / mol. The proportion of free OH groups is preferably 0.5 to 5 wt.%, based on the total weight of the polyester.

[0019] Silanes can have 1 to 10 C atoms, preferably 2 to 6 C atoms. They can contain amino, alkyl, and / or alkoxy groups with 1 to 10 C atoms, preferably 1 to 6 C atoms.

[0020] Siloxanes include, for example, cyclosiloxanes and / or polysiloxanes, where the siloxane monomer unit has one to 12 carbon atoms. They can carry alkyl, alkenyl (such as vinyl), aryl (such as phenyl), amino, alkoxy, or H groups in the side groups. Alkyl groups are preferred, with methyl (polydimethylsiloxane PDMS), methoxy, or ethoxy groups being particularly preferred. Suitable siloxanes are offered, for example, by Dow Corning (USA) - Dowsil products, Evonik (Germany) - Tegophobe 6600, Wacker (Germany) - TES28, and Momentive (USA) - Silquest products. The aforementioned polymers can be used, in particular, in the form of solutions or dispersions.

[0021] In a preferred embodiment, the mass ratio of (polycarbodiimide compound a + paraffin wax b) : polymer c is 10:90 to 90:10, preferably 70:30 to 95:5.

[0022] The coating composition preferably comprises at least one solvent d. This includes both water and organic solvents, with water or aqueous mixtures being preferred. Water and aqueous mixtures are advantageous because they are particularly environmentally friendly. Solvent mixtures are preferably homogeneous. Suitable organic solvents are alkanes, including branched alkanes, preferably having 10 to 20 carbon atoms, alcohols having 1 to 6, preferably 1 to 4, carbon atoms, and esters such as acetates of alcohols having 1 to 10 carbon atoms. Ethyl acetate is less preferred because it is explosive. For aqueous mixtures, hydrophilic organic solvents that are miscible with water, such as alcohols, are particularly suitable. The proportion of solvent is preferably 20 to 95 wt. %, based on the total weight of the composition.

[0023] For water-free coatings, alkyd resins, silanes, or siloxanes are particularly chosen as polymers. Water-based coatings preferably contain acrylate resins, polyurethane-modified polyesters, silanes, or siloxanes as polymers.

[0024] The coating composition may contain auxiliaries such as surfactants, surface-active agents, coalescing solvents, antifreeze agents, emulsifiers, or stabilizers against one or more microorganisms. Suitable auxiliaries are disclosed in US 11124918 B2. It is preferred that the coating composition be homogeneous. The proportion of auxiliaries is preferably 0.1 to 20 wt. %, based on the total weight of the composition.

[0025] The coating composition may contain 1 to 10 wt.%, based on the total weight of the composition, colorants such as dyes or pigments. These can, for example, mask the lines created during milling or the appearance of various materials. In particular, these colorants should not affect the water resistance and repellency.

[0026] To prepare the coating composition, the individual components can be added and mixed together, for example, using a stirrer. The individual components can be dissolved beforehand in suitable solvents.

[0027] Suitable substrates are floor coverings, with indoor flooring being preferred. These include homogeneous or heterogeneous plastic flooring, e.g., polyvinyl chloride, polyolefins, rubber, linoleum, or quartz vinyl. Cork is also suitable. The aforementioned floorings are resilient flooring. Furthermore, laminate flooring, parquet, including prefinished parquet, and plank flooring can be included. The latter are considered hard flooring. They are typically made of wood such as solid wood, veneer, or chipboard. Mineral substrates can also be included, with resilient and hard flooring being preferred. Carpets are not included.

[0028] The flooring can be homogeneous, i.e., made of a single material, or a mixture. Examples include flooring such as solid polymer core (SPC) or wood-plastic compound (WPC). The flooring can also be multi-layered, such as cushioned vinyl or laminate, which may include high-density fiberboard (HDF) or medium-density fiberboard (MDF). The flooring can, for example, have a foam coating. The flooring can include a decorative top layer and, for example, be patterned or plain-colored.

[0029] The coating composition can be applied to the edges of the floor coverings, the top or bottom surface, or to the entire surface. The coating composition is applied to the edges of floor coverings (often in the form of floor panels) using a transfer technique, in which the composition is first applied to a wheel or roller and then transferred by the wheel or roller to the edge of the panel.

[0030] This application method is similar to that described in WO 2006 / 038867. The solvent-based or water-based mixture may have a low viscosity, so it is not easily absorbed by the wheel and flows easily from the wheel back into the fluid reservoir.

[0031] In addition to transfer application, the composition according to the invention can be applied by spraying, particularly automated, for example, using a high-pressure spraying method, or by manual application such as a brush or roller. The advantage of this application is that a higher layer thickness can be achieved, which improves water resistance.

[0032] The coating composition is preferably applied in an amount of 0.1 to 30 g / m 2 corresponds, preferably 1 to 10 g / m 2 (dry layer).

[0033] The invention further provides fluorine-free coating compositions comprising at least one polymer c selected from alkyd resins, acrylate resins, polyurethane-modified polyesters, silanes, siloxanes, or mixtures thereof, and preferably at least one polycarbodiimide compound a, wherein the at least one polycarbodiimide compound has at least two hydrocarbon groups, each having at least 4 carbon atoms. The composition preferably contains at least one paraffin wax b. Furthermore, the composition preferably contains at least one solvent d. The definitions of polymer, polycarbodiimide, paraffin wax, and solvent have already been described above.

[0034] A further aspect of the invention is a floor covering partially or completely coated with the coating composition according to the invention. Preferred floor coverings have already been mentioned above. Examples

[0035] Uncoated MDF / HDF laminate boards were coated with coating compositions. The contact angle and edge swelling were measured to determine the impregnation quality.

[0036] Examinations

[0037] Edges of raw, uncoated MDF / HDF laminate boards are coated using a brush; drying: at least 24 h at room temperature; water drops (0.2 mL to 0.3 mL) are placed on the edge using a contact angle measuring device (OK 15E10); contact angle measurement

[0038] < 90°: hydrophil

[0039] > 90° to 130°: hydrophobic

[0040] > 130°: superhydrophob

[0041] Swelling of the edge

[0042] Drying times: at least 24 h at room temperature

[0043] Raw, uncoated MDF / HDF laminate boards, each with tongue or groove, 7 x 15 cm, are measured with a thickness gauge at various points; the boards are then coated with a brush; application quantities are determined by back weighing and the application quantity is calculated and expressed in g / m 2 determined (approx. 2 to 5 g / m 2 ); Laminate is clicked onto the tongue and groove to tension and the clicked joints are moistened with a wet cloth of a predefined weight; visual inspection and thickness measurement after 12 hours

[0044] 1 very strong swelling

[0045] 2 strong swellings

[0046] 3 slight swellings

[0047] 4 barely visible swellings

[0048] 5 No swelling using a thickness gauge (Käfer FD50); the thickness should be a maximum of 0.1 mm. Examples

[0049] Table 1. Aqueous coating compositions Table 2. Determination of the impregnating effect of aqueous coating compositions

[0050] Table 3. Non-aqueous coating compositions

[0051] Table 4. Determination of the impregnating effect of non-aqueous coating compositions Examples 1 to 4 demonstrate that the coating compositions according to the invention exhibit a high hydrophobic, impregnating effect on laminate edges and that no swelling occurs due to water contact.

Claims

Patent claims 1. Use of a fluorine-free coating composition comprising a. at least one polycarbodiimide compound, wherein preferably the at least one polycarbodiimide compound has at least two hydrocarbon groups, each having at least 4 carbon atoms, for impregnating floor coverings, excluding carpets.

2. Use according to claim 1, characterized in that the coating composition b. contains at least one paraffin wax.

3. Use according to claim 2, characterized in that the mass ratio of paraffin wax to polycarbodiimide is 3:7 to 7:

3.

4. Use according to one of the preceding claims, characterized in that the coating composition further comprises c. at least one polymer selected from alkyd resins, acrylate resins, polyurethane-modified polyesters, silanes, siloxanes or mixtures thereof.

5. Use according to claim 4, characterized in that the mass ratio of (a+b):c is 10:90 to 90:

10.

6. Use according to one of the preceding claims, characterized in that the coating composition further comprises d. at least one solvent.

7. Use according to claim 6, characterized in that a solvent comprising water is selected.

8. Fluorine-free coating composition comprising a. at least one polymer selected from alkyd resins, acrylate resins, polyurethane-modified polyesters, silanes, siloxanes or mixtures thereof, and b. preferably at least one polycarbodiimide compound, wherein the at least one polycarbodiimide compound has at least two hydrocarbon groups, each having at least 4 carbon atoms.

9. Fluorine-free coating composition according to claim 8, characterized in that the composition contains at least one paraffin wax.

10. Coating composition according to one of claims 8 or 9, characterized in that it contains at least one solvent.

11. Floor covering coated with a fluorine-free coating composition according to one of claims 8 to 10.

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