Method for providing a polymer-based binder and polymer-based binder

Abstract

The invention relates to a process for providing a polymer-based binder by radical polymerization of at least one ethylene unsaturated monomer, wherein the at least one ethylene unsaturated monomer serves as solvent and reactant, comprising the steps: a) Providing a reaction mixture comprising the at least one ethylene unsaturated monomer, at least one polymerization initiator and at least one polymerization regulator, wherein the reaction mixture contains essentially no other solvents besides the at least one ethylene unsaturated monomer; b) Polymerizing the reaction mixture at a first temperature of 80 °C to 100 °C to form a solution comprising a polymer in the at least one ethylene unsaturated monomer; c) Terminating the polymerization reaction upon reaching a conversion rate of 15% to 30%, preferably 18% to 25%, of the at least one ethylene unsaturated monomer used by cooling the solution to a second temperature and optionally adding a polymerization inhibitor; a polymer-based binder is provided.

Description

[0001] The invention relates to a method for providing a polymer-based binder.

[0002] The invention further relates to a polymer-based binder.

[0003] The invention further relates to the use of a polymer-based binder.

[0004] Curable casting compounds are used for the production of molded plastic parts, particularly in sanitary or kitchen applications, such as kitchen sinks, worktops, bathtubs, washbasins, or the like. These curable casting compounds typically comprise a binder and a filler to improve the mechanical properties of the molded plastic parts, as is known, for example, from DE 38 32 351 A1 or WO 2005 / 071000 A1.

[0005] Methods for providing the binder material are known that are based on dissolving acrylic glass (PMMA) in mixtures of mono- and polyfunctional acrylic monomers. In these methods, the acrylic glass is dissolved in reaction mixtures of methyl methacrylate and multifunctional (meth)acrylates for extended periods. Such methods are disclosed, for example, in DE 10 2004 055 365 A1, DE 10 2019 125 777 A1, and EP 4 406 984 A1. The long dissolution times required and the introduction of byproducts from the production and processing of the acrylic glass used prove to be disadvantages of these methods.This can lead to variations in properties during the production and processing of such binder materials, which can have a detrimental effect on the casting compounds produced with these materials and the plastic molded parts formed from them, such as kitchen sinks or worktops for the kitchen and / or sanitary area.

[0006] One object of the present invention is therefore to provide a method for ordering a polymer-based binder that enables high product purity, reduces production times and reduces variations in properties in the casting compound production associated with the binder production and in the plastic molded parts produced therefrom.

[0007] Another object of the present invention is to provide an alternative method for providing a polymer-based binder.

[0008] The present invention solves the aforementioned problems with a method for providing a polymer-based binder by radical polymerization of at least one ethylene unsaturated monomer, wherein the at least one ethylene unsaturated monomer serves as solvent and reactant, and the method comprises the following steps: a) Providing a reaction mixture comprising the at least one ethylene unsaturated monomer, at least one polymerization initiator and at least one polymerization regulator, wherein the reaction mixture contains essentially no other solvents besides the at least one ethylene unsaturated monomer; b) Polymerizing the reaction mixture at a first temperature of 80 °C to 100 °C to form a solution comprising a polymer in the at least one ethylene unsaturated monomer; c) Terminating the polymerization reaction upon reaching a conversion level of 15% to 30%, preferably 18% to 25%, of the at least one ethylene unsaturated monomer used by cooling the solution to a second temperature and optionally adding a polymerization inhibitor; wherein a polymer-based binder is provided.

[0009] The present invention also solves the aforementioned problems by means of a polymer-based binder produced by a method according to one of claims 1-19.

[0010] The present invention also solves the aforementioned problems by using a polymer-based binder according to claim 20 or 21 for the production of a plastic molded part for the kitchen and / or sanitary sector, in particular kitchen sinks and worktops for kitchens.

[0011] The term "conversion rate" is to be understood in the broadest sense and refers, particularly in the claims and preferably in the description, to the ratio of the amount of the reacted at least one ethylene unsaturated monomer to the amount of monomer used, expressed as a percentage. The conversion rate is thus the difference between the amount of monomer used and the remaining monomer in relation to the amount of monomer used. Unless otherwise specified, the conversion rate refers to the total amount of ethylene unsaturated monomers used. Methods for determining the conversion rate are known to those skilled in the art and include, for example, gas chromatography (GC), nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, viscosity measurements, or gravimetric methods.

[0012] The term "sanitary" is to be understood in the broadest sense and refers, particularly in the requirements, preferably in the description, generally to the kitchen area, the bathroom or laundry area, as well as the heating area.

[0013] One of the advantages achieved is the provision of a high-purity binder, minimizing process influences from foreign material sources. This is particularly true because the need to dissolve pre-made polymers, such as acrylic glass (PMMA), is eliminated, thus reducing the introduction of additives, degradation products, and process-related impurities from their manufacture and processing. This significantly improves the reproducibility of the binder properties of the polymer-based binder and the reproducibility of the casting compound properties of a casting compound produced with it. A further advantage of the proposed process is the reduction in production time.Furthermore, the use of at least one ethylene unsaturated monomer as solvent and reactant enables the reaction to be carried out without the addition of further solvents, thus eliminating the need for separate solvent separation steps before using the provided polymer-based binder and reducing energy and material consumption.

[0014] In solution polymerization, the monomer phase simultaneously acts as both reactant and solvent, so the resulting polymer exists as a solution within the monomer phase. Particularly suitable ethylene-unsaturated monomers include acrylates, methacrylates, vinyl aromatics, N-vinyl lactams, and N-vinylamides.

[0015] Further important features, advantages and further embodiments of the invention are described below or become apparent therein.

[0016] According to an advantageous embodiment of the invention, the at least one ethylene unsaturated monomer is selected from the group consisting of acrylates, methacrylates, vinyl aromatics, N-vinyl lactams and N-vinylamides, preferably from the group consisting of acrylates and methacrylates, wherein the acrylates and / or methyl acrylates are preferably selected from the group consisting of epoxy acrylates, epoxy methacrylates, aliphatic acrylates, aromatic acrylates, aromatic methacrylates, urethane acrylates, urethane methacrylates, polyester acrylates, polyester methacrylates, silicone acrylates, silicone methacrylates, silicone urethane acrylates, silicone urethane acrylate methacrylates, silicone polyester acrylates and silicone polyester methacrylates and combinations thereof, preferably the at least one ethylene unsaturated monomer is methyl methacrylate.Suitable acrylates include, for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, and hydroxypropyl acrylate. Suitable methacrylates include, for example, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate. Suitable vinyl aromatics include, for example, styrene and vinyltoluene. A suitable N-vinyllactam is, for example, N-vinyl-2-pyrrolidone. A suitable N-vinylamide is, for example, N-vinylformamide. This allows the properties of the resulting polymer to be specifically tailored to the respective requirements.

[0017] According to a further advantageous embodiment of the invention, the polymerization regulator is selected from the group consisting of thiols, preferably a thiol selected from the group consisting of dodecyl mercaptan, mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and tert-butyl mercaptan or salts thereof, wherein the polymerization regulator is preferably a thioglycolate. Dodecyl mercaptan particularly includes n-dodecyl mercaptan, TDDM, and tert-dodecyl mercaptan. Mercaptoethanol particularly includes 2-mercaptoethanol.

[0018] According to a further advantageous embodiment of the invention, the polymerization regulator comprises a weight fraction of 0.1 wt.% to 3.0 wt.% of the total mass of the provided reaction mixture, preferably 0.15 wt.% to 1.5 wt.%, and preferably 0.2 wt.% to 0.5 wt.%. For example, the weight fraction of the polymerization regulator in the total mass of the provided reaction mixture can be 0.1 wt.%, 0.15 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.75 wt.%, 1.0 wt.%, 1.5 wt.%, 2.0 wt.%, or 3.0 wt.%. The targeted use of such polymerization regulators in the specified amounts enables precise control of the chain length and molecular weight of the resulting polymer. This allows the viscosity of the binder to be optimally adapted to the respective requirements.

[0019] According to a further advantageous embodiment of the invention, the polymerization initiator is selected from the group consisting of azo compounds and organic peroxides. Suitable organic peroxides include, in particular, hydroperoxides and peroxycarboxylic acid esters, for example, cumene hydroperoxide, tert-butyl hydroperoxide, dibenzoyl peroxide, di-tert-butyl peroxide, di(4-tert-butylcyclohexyl)peroxydicarbonate, and dilauroyl peroxide. Suitable azo compounds include, in particular, 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN), 1,1'-azobis(cyclohexanecarbonitrile) (ACHN), and 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN).

[0020] According to a further advantageous embodiment of the invention, the polymerization initiator comprises a weight fraction of 0.001 wt.% to 0.1 wt.% of the total mass of the provided reaction mixture, preferably 0.005 wt.% to 0.05 wt.%, and more preferably 0.01 wt.% to 0.03 wt.%. For example, the weight fraction of the polymerization initiator in the total mass of the provided reaction mixture can be 0.001 wt.%, 0.005 wt.%, 0.01 wt.%, 0.02 wt.%, 0.03 wt.%, 0.04 wt.%, 0.05 wt.%, 0.075 wt.%, or 0.1 wt.%. The use of such polymerization initiators ensures a reliable and controlled start of the polymerization reaction, thereby increasing process reliability. Such a dosage of the polymerization initiator allows for targeted control of the reaction rate and end-product properties, resulting in a uniform polymer structure.

[0021] According to a further advantageous embodiment of the invention, a demolding agent is added to the reaction mixture during cooling, preferably selected from the group consisting of long-chain fatty acid amides, long-chain fatty acid esters, metal soaps of long-chain fatty acids, and silicones. Suitable long-chain fatty acid amides are, for example, erucamide and oleamide; a suitable long-chain fatty acid ester is, for example, glycerol monostearate; a suitable metal soap of long-chain fatty acids is, for example, calcium stearate; and a suitable silicone is, for example, polydimethylsiloxane. Preferably, the demolding agent is stearic acid.

[0022] The term “long-chain fatty acid” is to be understood in the broadest sense and refers, particularly in the claims, preferably in the description, to fatty acids with a total number of 14 to 22 carbon atoms, including saturated and unsaturated fatty acids.

[0023] According to a further advantageous embodiment of the invention, the demolding agent has a weight fraction of 0.05 wt.% to 1.0 wt.% of the total mass of the reaction mixture, preferably 0.1 wt.% to 0.5 wt.%, preferably 0.2 wt.% to 0.4 wt.%. For example, the weight fraction of the demolding agent in the total mass of the reaction mixture can be 0.05 wt.%, 0.1 wt.%, 0.2 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.75 wt.%, or 1.0 wt.%.

[0024] The addition of such a demolding agent in such quantities improves the required detachability of the reacted resin from the surfaces of the molding tool in the subsequent processing as a casting compound.

[0025] According to a further advantageous embodiment of the invention, the polymerization inhibitor is selected from the group consisting of hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-4-methylphenol, and phenothiazine. Preferably, the polymerization inhibitor is 2,6-di-tert-butyl-4-methylphenol.

[0026] According to a further advantageous embodiment of the invention, the polymerization inhibitor has a weight fraction of 0.0025 wt.% to 0.03 wt.% of the total mass of the reaction mixture, preferably 0.005 wt.% to 0.020 wt.%, preferably 0.0075 wt.% to 0.01 wt.%.

[0027] The targeted use of such inhibitors, especially in such quantities, enables a controlled slowing down or targeted termination of the polymerization in order to effectively prevent overreaction and to ensure consistently high product quality as well as improved purity of the final product.

[0028] According to a further advantageous embodiment of the invention, the second temperature is at most 30 °C, preferably at most 25 °C, and more preferably at most 20 °C. For example, the second temperature can be 0 °C, 5 °C, 10 °C, 15 °C, 20 °C, 21 °C, 22 °C, 23 °C, 24 °C, 25 °C, 26 °C, 27 °C, 28 °C, 29 °C, or 30 °C. By selectively cooling to such a second temperature, the polymerization reaction is effectively stopped. A further advantage of the process is that it can be carried out both continuously and batchwise, thus enabling high flexibility with regard to production conditions and optimal adaptation to different production volumes and requirements.

[0029] According to a further advantageous embodiment of the invention, the process is carried out as a batch process, preferably using a stirred tank reactor, preferably a stirred tank reactor with flow baffles. The use of a stirred tank reactor with flow baffles ensures homogeneous mixing of the reaction mixture and thus uniform polymerization.

[0030] According to a further advantageous embodiment of the invention, the first temperature of the batch process is 80 °C to 90 °C, preferably 83 °C to 87 °C. For example, the first temperature can be 80.0 °C, 80.5 °C, 81.0 °C, 81.5 °C, 82.0 °C, 82.5 °C, 83.0 °C, 83.5 °C, 84.0 °C, 84.5 °C, 85.0 °C, 85.5 °C, 86.0 °C, 86.5 °C, 87.0 °C, 87.5 °C, 88.0 °C, 88.5 °C, 89.0 °C, 89.5 °C, or 90.0 °C. Such a setting of the reaction temperature allows for optimal control of the polymerization rate and molecular weight distribution.

[0031] According to a further advantageous embodiment of the invention, setting the first temperature comprises: - Heating the reaction mixture to a starting temperature of at least 70 °C using external heat input; - Ending the external heat supply; and - Removal of the heat of reaction.

[0032] For example, the starting temperature can be 70.0 °C, 70.5 °C, 71.0 °C, 71.5 °C, 72.0 °C, 72.5 °C, 73.0 °C, 73.5 °C, 74.0 °C, 74.5 °C, 75.0 °C, 75.5 °C, 76.0 °C, 76.5 °C, 77.0 °C, 77.5 °C, 78.0 °C, 78.5 °C, 79.0 °C, 79.5 °C or 80.0 °C.

[0033] Initially heating the reaction mixture to this starting temperature enables an effective and controlled start to the polymerization reaction, resulting in uniform initiation and improved control of the reaction progress. Subsequently stopping the external heat supply prevents an uncontrolled temperature increase and contributes to process stabilization. Furthermore, the process heat generated during the exothermic polymerization reaction can be specifically utilized to maintain the reaction and reduce energy consumption, further improving the energy efficiency of the process. By selectively dissipating the reaction heat, overheating of the reaction mixture can be avoided, increasing process reliability.

[0034] According to a further advantageous embodiment of the invention, the degree of conversion is monitored by determining the viscosity, preferably using an inline viscometer. Continuous viscosity monitoring enables precise determination of the reaction progress, ensuring high process control and consistent product quality.

[0035] According to a further advantageous embodiment of the invention, step c) is initiated at a viscosity of 35 mPas to 45 mPas. For example, the viscosity can be 35 mPas, 36 mPas, 37 mPas, 38 mPas, 39 mPas, 40 mPas, 41 mPas, 42 mPas, 43 mPas, 44 mPas, or 45 mPas. If the next process step is initiated at such a defined viscosity, a consistent polymer structure and thus consistent processing properties can be achieved.

[0036] According to a further advantageous embodiment of the invention, the process is carried out as a continuous process, preferably using a static mixer-reactor with at least two successive zones at different temperatures. Static mixer-reactors are specially designed shell-and-tube heat exchangers that enable effective mixing and controlled heat transfer, even in viscous media. Continuous process operation in such reactors and targeted temperature zoning in several series-connected zones allow for optimal control of the polymerization reaction, resulting in high yield, consistent product quality, and reduced energy consumption. Suitable static mixer-reactors include, for example, SMR mixer-reactors from Sulzer.

[0037] According to a further advantageous embodiment of the invention, a first zone has the first temperature and a second zone has the second temperature. Cooling the reaction mixture in the second zone to the second temperature enables the polymerization reaction to be effectively stopped. The polymerization time thus results in particular from the residence time of the reaction mixture in the first zone.

[0038] According to a further advantageous embodiment of the invention, the first temperature is between 90 °C and 100 °C. For example, the first temperature of the continuous process can be 90.0 °C, 90.5 °C, 91.0 °C, 91.5 °C, 92.0 °C, 92.5 °C, 93.0 °C, 93.5 °C, 94.0 °C, 94.5 °C, 95.0 °C, 95.5 °C, 96.0 °C, 96.5 °C, 97.0 °C, 97.5 °C, 98.0 °C, 98.5 °C, 99.0 °C, 99.5 °C, or 100.0 °C. Such a reaction temperature in the continuous process allows for a rapid and controlled conversion of the monomers.

[0039] According to a further advantageous embodiment of the invention, the polymer-based binder has a PMMA solids content of 18 wt.% to 25 wt.% and / or PMMA with a number-average molecular weight (Mn) of 75,000 g / mol to 115,000 g / mol and / or a weight-average molecular weight (Mw) in the range of 130,000 g / mol to 215,000 g / mol and / or a polydispersity (D) of at most 2.0. For example, the PMMA solids content can be 18 wt.%, 19 wt.%, 20 wt.%, 21 wt.%, 22 wt.%, 23 wt.%, 24 wt.%, or 25 wt.%. For example, the number-mean molecular weight (Mn) of PMMA can be 75,000 g / mol, 80,000 g / mol, 85,000 g / mol, 90,000 g / mol, 95,000 g / mol, 100,000 g / mol, 105,000 g / mol, 110,000 g / mol or 115,000 g / mol. For example, the weight-mean molecular weight (Mw) of PMMA can be 130,000 g / mol, 140,000 g / mol, 150,000 g / mol, 160,000 g / mol, 170,000 g / mol, 180,000 g / mol, 190,000 g / mol, 200,000 g / mol or 215,000 g / mol.For example, the polydispersity (D) of PMMA can be 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0. A polymer-based binder formulated in this way is ideally suited for the production of molded plastic parts, especially for applications in kitchens and / or sanitary facilities.

[0040] Suitable methods for determining the solids content of a composition are known to those skilled in the art and include, for example, gravimetric methods, in particular the determination of the mass loss or the residue after separation of the volatile components.

[0041] Suitable methods for determining the number-mean molecular weight (Mn), the weight-mean molecular weight (Mw) and the polydispersity (D) are known to those skilled in the art and include, for example, gel permeation or size exclusion chromatography (GPC / SEC), preferably with refractive index detection and / or in combination with a method of light scattering detection, such as multi-angle laser light scattering (MALS).

[0042] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0043] Preferred embodiments and configurations of the invention are shown in the drawing and are explained in more detail in the following description.

[0044] This shows Fig.1 Steps of a method according to an embodiment of the present invention.

[0045] In Fig. Figure 1 shows the steps of a process for providing a polymer-based binder by radical polymerization of at least one ethylene-unsaturated monomer, wherein the at least one ethylene-unsaturated monomer serves as both solvent and reactant. The process comprises the following steps: - Providing S1 of a reaction mixture comprising the at least one ethylene unsaturated monomer, at least one polymerization initiator and at least one polymerization regulator, wherein the reaction mixture contains essentially no other solvents besides the at least one ethylene unsaturated monomer; - Polymerizing S2 of the reaction mixture at a first temperature of 80 °C to 100 °C to form a solution comprising a polymer in which at least one ethylene unsaturated monomer is found; - Terminate step S3 of the polymerization reaction upon reaching a conversion level of 15% to 30%, preferably 18% to 25%, of the at least one ethylene unsaturated monomer used by cooling the solution to a second temperature and optionally adding a polymerization inhibitor.

[0046] It was found that the inventive method provides a binder with high purity and uniform product properties in a short production time. Comparative example

[0047] A polymer-based binder is obtained essentially by dissolving PMMA in MMA over a period of 12 to 14 hours, with the addition of a demolding agent.

[0048] The composition of the approach according to the comparative example is shown in the following Table 1, where the levels of the individual components are given in weight percent. Table 1 component % by weight MMA 79,5 PMMA (Lucite Diakon MH254) 20,2 Stearic acid 0,3 Example 1

[0049] A polymer-based binder is produced in a discontinuous process in a stirred tank reactor equipped with an inline viscometer for continuous viscosity measurement, with a capacity of 1,000-2,000 l within 2 to 4 hours.

[0050] For this purpose, a reaction mixture is provided by supplying methyl methacrylate (MMA) as a reactant and solvent, an organic peroxide as a polymerization initiator, and a polymerization regulator.

[0051] The reaction mixture is heated to a starting temperature of at least 70 °C by means of external heat input.

[0052] The external heat supply is then stopped and the exothermic polymerization reaction continues at a first temperature, whereby cooling is used to prevent the temperature from exceeding 90 °C.

[0053] The reaction progress is continuously monitored by means of an inline viscometer via the change in viscosity.

[0054] Upon reaching a viscosity of 35 mPas to 45 mPas, typically after a reaction time of 2.0 to 3.5 hours, the polymerization reaction is stopped by cooling to a second temperature in the range of 20 °C to 30 °C. During cooling, stearic acid is added as a demolding agent. A polymerization inhibitor may also be added if necessary.

[0055] The composition of the reaction mixture according to Example 1 is shown in Table 2 below, with the amounts of each component given in weight percent. Table 2 component % by weight MMA 99,5 Organic peroxide 0,02 Polymerization regulator 0,20 Polymerization inhibitor 0,01 Stearic acid 0,27

[0056] The resulting MMA / PMMA solution exhibits an average viscosity of approximately 190 mPas at 18 °C and a PMMA solids content of 18 to 20% after the reaction is complete. The PMMA precipitate isolated from the MMA / PMMA solution has a number-mean molecular weight (Mn) of approximately 105,000 g / mol (±5,000 g / mol), a weight-mean molecular weight (Mw) of approximately 200,000 g / mol (±10,000 g / mol), and a polydispersity (D) of approximately 1.8 (±0.05).

[0057] The polymer-based binder provided according to the above-described method can be used directly for the production of curable casting compounds for plastic molded parts. Example 2

[0058] A polymer-based binder is produced in a continuous process in a static mixer-reactor with successive temperature zones.

[0059] For this purpose, a reaction mixture is provided which contains methyl methacrylate (MMA) as a reactant and solvent, an organic peroxide as a polymerization initiator, and a polymerization regulator.

[0060] A Sulzer SMR mixer with a diameter of DN 300 and a volume of 212 liters is used as the reactor. The reaction mixture is continuously fed through the static mixer-reactor at a mass flow rate of approximately 200 kg / h, resulting in a conversion rate of 15% to 30% of the methyl methacrylate used within the polymerization time.

[0061] For this purpose, the mixture is heated in a first zone of the reactor to a first temperature in the range of 90 °C to 100 °C, so that the radical polymerization is initiated and proceeds in a controlled manner.

[0062] After passing through the first zone, the reaction mixture enters a second zone where the temperature is lowered to a second temperature of 20 °C to 30 °C to complete the polymerization reaction.

[0063] During cooling, stearic acid is added as a demolding agent. A polymerization inhibitor may also be added if necessary.

[0064] The composition of the reaction mixture corresponds to that in Table 2 of Example 1. The amounts of the individual components in weight percent are given there.

[0065] The MMA / PMMA solution obtained at the reactor outlet has an average viscosity of approximately 300 mPas at 18 °C and a PMMA solids content of 22% to 24%. The PMMA precipitate isolated from the MMA / PMMA solution has a number-mean molecular weight (Mn) of approximately 80,000 g / mol (±2,000 g / mol), a weight-mean molecular weight (Mw) of approximately 144,000 g / mol (±1,000 g / mol), and a polydispersity (D) of approximately 1.8 (±0.05).

[0066] The polymer-based binder provided according to the above-described method can be used directly for the production of curable casting compounds for plastic molded parts.

[0067] In summary, at least one embodiment of the present invention may have at least one of the following features and / or may provide at least one of the following advantages: - Cost-effective and simple production. - Reduced production time. - High purity of the provided binder. - Uniform product properties of the binder and the plastic molded parts produced with it.

[0068] Although the present invention has been described using preferred embodiments, it is not limited to these, but can be modified in many ways. Reference symbol list S1 Providing a reaction mixture comprising the at least one ethylene unsaturated monomer, at least one polymerization initiator and at least one polymerization regulator, wherein the reaction mixture contains essentially no other solvents besides the at least one ethylene unsaturated monomer S2 Polymerization of the reaction mixture at a first temperature of 80 °C to 100 °C to form a solution comprising a polymer in which at least one ethylene unsaturated monomer S3 Termination of the polymerization reaction upon reaching a conversion level of 15% to 30%, preferably 18% to 25%, of the at least one ethylene unsaturated monomer used, by cooling the solution to a second temperature and optionally adding a polymerization inhibitor QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 38 32 351 A1

[0004] WO 2005 / 071000 A1

[0004] DE 10 2004 055 365 A1

[0005] DE 10 2019 125 777 A1

[0005] EP 4 406 984 A1

[0005]

Claims

[1] Method for providing a polymer-based binder by radical polymerization of at least one ethylene unsaturated monomer, wherein the at least one ethylene unsaturated monomer serves as solvent and reactant, comprising the steps: a) Providing (S1) a reaction mixture comprising the at least one ethylene unsaturated monomer, at least one polymerization initiator and at least one polymerization regulator, wherein the reaction mixture contains essentially no other solvents besides the at least one ethylene unsaturated monomer; b) Polymerizing (S2) the reaction mixture at a first temperature of 80 °C to 100 °C to form a solution comprising a polymer in the at least one ethylene unsaturated monomer; c) Terminating (S3) the polymerization reaction upon reaching a conversion level of 15% to 30%, preferably 18% to 25%, of the at least one ethylene unsaturated monomer used by cooling the solution to a second temperature and optionally adding a polymerization inhibitor; a polymer-based binder is provided. [2] Method according to claim 1, wherein the at least one ethylene unsaturated monomer is selected from the group consisting of acrylates, methacrylates, vinyl aromatics, N-vinyl lactams and N-vinylamides, preferably wherein the at least one ethylene unsaturated monomer is selected from the group consisting of acrylates and methacrylates, wherein the acrylates and / or methyl acrylates are preferably selected from the group consisting of epoxy acrylates, epoxy methacrylates, aliphatic acrylates, aromatic acrylates, aromatic methacrylates, urethane acrylates, urethane methacrylates, polyester acrylates, polyester methacrylates, silicone acrylates, silicone methacrylates, silicone urethane acrylates, silicone urethane acrylate methacrylates, silicone polyester acrylates and silicone polyester methacrylates and combinations thereof, preferably wherein the at least one ethylene unsaturated monomer is methyl methacrylate. [3] Method according to claim 1 or 2, wherein the polymerization regulator is selected from the group of thiols, preferably the polymerization regulator is selected from the group consisting of dodecyl mercaptan, mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate and tert-butyl mercaptan or salts thereof, wherein the polymerization regulator is preferably a thioglycolate. [4] Method according to any one of claims 1 to 3, wherein the polymerization regulator has a weight fraction of 0.1 wt.% to 3.0 wt.% of the total mass of the provided reaction mixture, preferably 0.15 wt.% to 1.5 wt.%, preferably 0.2 wt.% to 0.5 wt.%. [5] Method according to any one of claims 1 to 4, wherein the polymerization initiator is selected from the group consisting of azo compounds and organic peroxides. [6] Method according to any one of claims 1 to 5, wherein the polymerization initiator has a weight fraction of 0.001 wt.% to 0.1 wt.% of the total mass of the reaction mixture provided, preferably 0.005 wt.% to 0.05 wt.%, preferably 0.01 wt.% to 0.03 wt.%. [7] Method according to any one of claims 1 to 6, wherein a demolding agent is added to the reaction mixture during cooling, preferably selected from the group consisting of long-chain fatty acid amides, long-chain fatty acid esters, metal soaps of long-chain fatty acids and silicones, wherein the demolding agent is preferably stearic acid. [8] Method according to any one of claims 1 to 7, wherein the demolding agent has a weight fraction of 0.05 wt.% to 1.0 wt.% of the total mass of the reaction mixture, preferably 0.1 wt.% to 0.5 wt.%, preferably 0.2 wt.% to 0.4 wt.%. [9] Method according to any one of claims 1 to 8, wherein the polymerization inhibitor is selected from the group consisting of hydroquinone, p-methoxyphenol, 2,6-di-tert-butyl-4-methylphenol and phenothiazine, wherein the polymerization inhibitor is preferably 2,6-di-tert-butyl-4-methylphenol. [10] Method according to any one of claims 1 to 9, wherein the polymerization inhibitor has a weight fraction of 0.0025 wt.% to 0.03 wt.% of the total mass of the reaction mixture, preferably 0.005 wt.% to 0.020 wt.%, preferably 0.0075 wt.% to 0.01 wt.%. [11] Method according to any one of claims 1 to 10, wherein the second temperature is at most 30 °C, preferably at most 25 °C, preferably at most 20 °C. [12] Method according to any one of claims 1 to 11, wherein the method is carried out as a batch process, preferably wherein a stirred tank reactor, preferably a stirred tank reactor with flow breakers, is used as the reactor. [13] Method according to claim 12, wherein the first temperature is 80 °C to 90 °C. [14] Method according to claim 12 or 13, wherein setting the first temperature comprises: - Heating the reaction mixture to a starting temperature of at least 70 °C using external heat input; - Ending the external heat supply; and - Removal of the heat of reaction. [15] Method according to any one of claims 12 to 14, wherein the degree of conversion is monitored by determining the viscosity, preferably by means of an inline viscometer. [16] Method according to claim 15, wherein step c) is initiated at a viscosity of 35 mPas to 45 mPas. [17] Method according to any one of claims 1 to 11, wherein the method is carried out as a continuous process, preferably wherein a static mixer reactor with at least two successive zones having different temperatures is used as the reactor. [18] Method according to claim 17, wherein a first zone has the first temperature and a second zone has the second temperature. [19] Method according to claim 17 or 18, wherein the first temperature is 90 °C to 100 °C. [20] Polymer-based binder produced by a method according to any one of claims 1 to 19. [21] Polymer-based binder according to claim 20, wherein the polymer-based binder has a PMMA solids content of 18 wt% to 25 wt%, and / or a PMMA with a number-average molecular weight (Mn) of 75,000 g / mol to 115,000 g / mol and / or a weight-average molecular weight (Mw) in the range of 130,000 g / mol to 215,000 g / mol and / or a polydispersity (D) of at most 2.

0. [22] Use of a polymer-based binder according to claim 20 or 21 for the production of a plastic molded part for the kitchen and / or sanitary sector, in particular kitchen sinks and kitchen worktops.

Images