Use of bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate as plasticizer in surface covering

Abstract

To provide a multilayer surface covering composed of a polyvinyl chloride (PVC) plasticizer composition capable of achieving a desired gelation rate without addition of a high-speed gelling agent.SOLUTION: There is provided a multilayer surface covering comprising: at least one layer derived from a filler-containing PVC plastisol; and at least one layer derived from a filler-free PVC plastisol, in which both plasticizer compositions each contain bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate. Such surface covering may be used as a floor covering or as an artificial leather.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to multilayer surface coatings, each coating comprising at least one layer derived from a filler-containing PVC plastisol and a filler-free PVC plastisol, the plastisol composition containing a plasticizer containing bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate (hereinafter 1,4-DEHCH). Such surface coatings can be used as floor coverings or artificial leather.

Background Art

[0002] Multilayer surface coatings, particularly floor coverings and artificial leather, are known and manufactured on an industrial scale. Such surface coatings consist of multiple layers. At least some of the layers are mainly composed of polyvinyl chloride (PVC), and it is necessary to add a plasticizer to improve properties such as stretchability and workability. The most well-known plasticizer for PVC in Europe is diisononyl phthalate (DINP), which is also standardly used in applications such as floor coverings and artificial leather. DINP is characterized by acceptable gelling properties, medium viscosity, and above all, low volatility. In particular, low volatility is important in the applications mentioned for reducing emissions during production and in the final product. During the production of flexible PVC articles, since the processing temperature is high, the plasticizer evaporates at least partially and then condenses and / or drips in a cooler place, leading to contamination and as a result, often causing production to stop, which may lead to economic disadvantages.

[0003] Indeed, DINP is one of the global standards. Market demand is also increasingly for phthalate-free plasticizers (Patent Document 1). Among phthalate-free plasticizers, diisononylcyclohexane-1,2-dicarboxylic acid (1,2-DINCH) is the most important. Terephthalates, such as di-2-ethylhexyl terephthalate (DEHT or DOTP), could also be used in large quantities with phthalates, especially DINP, but they are increasingly not generally accepted. This is because they are classified as phthalates. However, these two types of plasticizers have lower gelation rates and higher volatility compared to DINP.

[0004] To compensate for the fragility of the gel, it is necessary to add a fast gelling agent. However, fast gelling agents are generally highly volatile, which increases the overall process volatility of the plasticizer composition. Furthermore, fast gelling agents are usually more expensive, so using them further increases the cost of the formulation. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] U.S. Patent Application Publication No. 2016 / 0326346 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The object of the present invention was to provide a multilayer surface coating comprising an advantageous plasticizer composition for an existing PVC plastisol layer. [Means for solving the problem]

[0007] The aforementioned problems can be achieved by the multilayer surface coating of the present invention as described in claim 1 of this application. Preferred embodiments of the present invention are shown in the dependent claims. Such a surface coating is a multilayer surface coating comprising at least one layer derived from a filler-containing PVC plastisol comprising PVC, a filler and a plasticizer composition, and at least one layer derived from a filler-free PVC plastisol comprising PVC and a plasticizer composition, wherein the plasticizer composition in the filler-containing PVC plastisol and the filler-free PVC plastisol each comprises bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate (1,4-DEHCH). [Effects of the Invention]

[0008] The performance of this plasticizer composition according to the present invention is improved overall when used in plastisols compared to other cyclohexanedicarboxylic acid esters or mixtures thereof. Therefore, the desired gelation rate of DINP can be achieved without the addition of a fast gelling agent. Furthermore, the viscosity of plastisols using the plasticizer composition according to the present invention is significantly lower compared to plastisols using DINP, thereby allowing the plastisol to diffuse rapidly or easily and / or increasing the filler content, which can be advantageously used to reduce formulation costs. Compared to other cyclohexanedicarboxylic acid esters (1,4-DINCH, 1,2-DINCH, 1,2-DEHCH, etc.), the gelation rate is improved, and improvements in processing speed and reductions in energy input during processing can be expected. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows the arrangement of the surface coating layers according to the present invention. [Figure 2] This figure shows the arrangement of the surface coating layers according to the present invention. [Figure 3] This figure shows the arrangement of the surface coating layers according to the present invention. [Modes for carrying out the invention]

[0010] In the context of this invention, the term "derived layer" means that each layer is obtained from the corresponding plastisol composition. For the production of the surface coating according to the present invention, the plastisols presented herein are used in liquid or free-flowing form, applied layer by layer, and then repeatedly pre-gelled at a temperature insufficient for complete gelation or foaming (100-150°C), thereby pre-drying the layer and making it possible to apply the next layer, and the final product can only be obtained at a temperature of 160-230°C, for example, in a "gelling tunnel." In this process, foaming and "adhesion (bonding)" of the individual layers also occur.

[0011] In principle, the layers of the surface coating according to the present invention may be arranged in any order. However, according to the present invention, it is preferable that the layer derived from filler-containing PVC plastisol be placed below the layer derived from filler-free PVC plastisol. One or more further layers and / or a carrier material such as polyester cloth, glass fleece, paper, or board may be present between the layer derived from filler-containing PVC plastisol and the layer derived from filler-free PVC plastisol. Preferably, the carrier material may also be present within the filler-containing layer.

[0012] A filler-containing PVC plastisol contains a filler and a plasticizer composition in addition to PVC. Various types of PVC can be used as the PVC for the filler-containing PVC plastisol. The PVC in the filler-containing PVC plastisol is preferably a paste-type PVC, a expander PVC, or a mixture of two or more of these PVC types. In other embodiments, the PVC is a mixture of two or more paste-type PVCs.

[0013] The difference between paste-type PVC and expander PVC generally lies in the manufacturing method and the particle size of the resulting PVC particles. Paste-type PVC can be manufactured by emulsion polymerization or microsuspension polymerization, resulting in PVC particles with a particle size of typically 1 to 40 μm. Expander PVC can be manufactured by suspension polymerization. The particle size of the resulting aggregated PVC particles is typically 80 to 200 μm. One effect of adding expander PVC is that it can lower the viscosity level of the plastisol even with a low plasticizer content, making the diffusion (spreading) of the plastisol easier.

[0014] The exact composition is essentially variable and can be adjusted to suit the corresponding application. In the case of surface coating according to the present invention, the filler-containing PVC plastisol preferably contains the plasticizer composition in a ratio of 35 to 80 parts by mass, preferably 40 to 75 parts by mass, per 100 parts by mass of PVC. The plasticizer composition contains bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate (1,4-DEHCH), but may contain one or more additional plasticizers. The corresponding plasticizers are known to those skilled in the art. 1,4-DEHCH is present in the plasticizer composition, particularly based on the plasticizer composition as a whole, in each case at a ratio of at least 50% by mass, preferably at least 65% by mass, and more preferably at least 80% by mass. In a particularly preferred embodiment, the plasticizer composition of the filler-containing PVC plastisol consists solely of 1,4-DEHCH.

[0015] The filler-containing PVC plastisol for multilayer surface coating according to the present invention preferably contains filler in a ratio of 50 to 200 parts by mass per 100 parts by mass of PVC, preferably 70 to 180 parts by mass per 100 parts by mass of PVC, and more preferably 85 to 170 parts by mass per 100 parts by mass of PVC. Fillers suitable for surface coating are known to those skilled in the art. In the context of the present invention, preferred fillers that can be used in the filler-containing PVC plastisol are calcium carbonate, magnesium carbonate, alumina (clay), calcium silicate, talc, calcium sulfate, calcium oxide, magnesium oxide, aluminum silicate, dolomite, silicon oxide, and diatomaceous earth. Calcium carbonate and magnesium carbonate are particularly preferred.

[0016] The filler-containing PVC plastisol may contain additives in addition to the above components. Examples of further additives include rheological additives that can reduce the viscosity of the plastisol, epoxidized vegetable oils such as epoxidized soybean oil (ESBO) as co-stabilizers, and heat stabilizers or defoamers that can lower the surface tension to make it easier to remove bubbles that form in the plastisol during manufacturing. Examples of rheological additives include VISCOBYK®-5120, VISCOBYK®-5130, and VISCOBYK®-4041. Known defoamers include products sold under the trade names of methylalkylpolysiloxane (e.g., available under the trademark name BYK®-3105) or polyalkylene derivatives (e.g., available under the trademark name BYK®-3155). Defoamers that do not contain silicone are preferred. Suitable heat stabilizers include lead salts, organotin compounds, barium / zinc compounds, cadmium compounds or zinc compounds, calcium / zinc stabilizers, and organic stabilizers (so-called OBS). Preferred heat stabilizers are barium / zinc compounds, calcium / zinc stabilizers, and organic stabilizers (so-called OBS). Each additive can be individually incorporated into the plastisol in an amount of up to 15 parts by mass per 100 parts by mass of PVC.

[0017] The multilayer surface coating may also include a carrier material. Various materials can be used as the carrier material for the surface coating described herein. Preferably, the carrier material for the multilayer surface coating consists of polyester fabric, glass nonwoven fabric, paper, or board. If a carrier material is present, at least the upper side, i.e., one side, is coated with filler-containing PVC plastisol. This is particularly applicable to paper and substrates. As a result of the coating, the fluid plastisol composition penetrates into the structure of the carrier material. Thus, in the context of the present invention, the carrier material forms part of the layer derived from the filler-containing PVC plastisol. Preferably, the carrier material is coated on both sides, i.e., the upper and lower sides, with filler-containing PVC plastisol, although this can also be achieved in one step. This impregnates or immerses the carrier material with filler-containing PVC plastisol, and then incorporates the carrier material into the layer derived from the filler-containing PVC plastisol.

[0018] A filler-free PVC plastisol contains at least one plasticizer composition in addition to PVC. As the name suggests, a filler-free PVC plastisol does not contain fillers, i.e., substances that can be considered fillers. The layer derived from the filler-free PVC plastisol is preferably transparent. Various PVCs can be used as the PVC in the filler-free PVC plastisol. The PVC in the filler-free PVC plastisol is preferably paste-like PVC, expander PVC, or a mixture of two or more of these PVCs. In other embodiments, the PVC is a mixture of two or more paste-like PVCs. The definitions and differences between paste-like PVC and expander PVC are as described above.

[0019] In the case of a filler-free PVC plastisol, it is preferably composed of at least one paste PVC and at least one extender PVC. The amounts of the paste PVC and the extender PVC can vary within a wide range and can be adjusted according to the requirements of a specific application. In a preferred embodiment, the paste PVC is present in an amount of 40% to 80% by mass, based on the total amount of PVC in the filler-free PVC plastisol, and the extender PVC is present in an amount of 20% to 60% by mass. It is clear that the combined amounts of the paste PVC and the extender PVC must add up to 100% by mass.

[0020] The composition of the filler-free PVC plastisol is basically variable and can be adjusted according to the corresponding application. In the case of the surface coating according to the present invention, the filler-free PVC plastisol preferably contains a plasticizer composition containing 1,4-DEHCH in an amount of 15 to 40 parts by mass per 100 parts by mass of PVC. The plasticizer composition contains bis(2-ethylhexyl) cyclohexane-1,4-dicarboxylate (1,4-DEHCH), but may contain one or more further plasticizers. The corresponding plasticizers are known to those skilled in the art. 1,4-DEHCH is present in the plasticizer composition, in particular based on the entire plasticizer composition, in each case in a ratio of at least 50% by mass, preferably at least 65% by mass, more preferably at least 80% by mass. According to the present invention, the plasticizer composition for the filler-free PVC plastisol preferably contains a high-speed gelling agent in addition to 1,4-DEHCH. The high-speed gelling agent may be present in the filler-free PVC plastisol in a ratio of up to 15 parts by mass per 100 parts by mass of PVC. Suitable high-speed gelling agents are glycol dibenzoate, dibutyl or dipentyl terephthalate, 2-ethylhexyl, isononyl or isodecyl benzoate, tributyl citrate, acetyl tributyl citrate, or hydrogenated phthalic or terephthalic acid esters having a C4-C7 alkyl chain.

[0021] The filler-free PVC plastisol can further contain additives and the described components. Examples of additional additives are rheology additives that can reduce the viscosity of the plastisol. Examples of known rheology additives include products sold under the trade names VISCOBYK®-5120, VISCOBYK®-5130, and VISCOBYK®-4041. The additives may be present in the filler-free PVC plastisol in a ratio of 3 to 12, preferably 4 to 10, parts by mass per 100 parts by mass of PVC.

[0022] Furthermore, the filler-free PVC plastisol may contain one or more heat stabilizers. Suitable heat stabilizers include lead salts, organotin compounds, barium / zinc compounds, cadmium compounds or zinc compounds, calcium / zinc stabilizers, and organic stabilizers (so-called OBS). Preferred heat stabilizers are barium / zinc compounds, calcium / zinc stabilizers, and organic stabilizers (so-called OBS). The ratio of the stabilizer in the filler-free PVC plastisol is preferably 1 to 4 parts by mass per 100 parts by mass of PVC.

[0023] For example, in the surface coating, there may be a further foamed layer derived from the foaming PVC plastisol on the back surface. Such a layer can improve the acoustic properties. In the floor covering, such a layer derived from the foamed PVC plastisol can be used to attenuate impact sound.

[0024] The further foamed layer derived from the foamed PVC plastisol comprises, in particular, PVC, a plasticizer composition containing at least bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate (1,4-DEHCH), one or more fillers, a blowing agent, a kicker, and optionally one or more further additives. The plasticizer composition of the further foamed layer of the foamed PVC plastisol may further contain a fast gelling agent. Suitable fast gelling agents include glycol dibenzoate, dibutyl or dipentyl terephthalate, 2-ethylhexyl, isononyl or isodecyl benzoate, tributyl citrate, acetyl tributyl citrate, or hydrogenated phthalates or terephthalates having C4-C7 alkyl chains.

[0025] The composition of the further foamed layer derived from the foamed PVC plastisol is, in principle, variable and can be adjusted according to the corresponding application. In the case of the surface coating according to the present invention, the further layer of foamed PVC plastisol preferably contains a plasticizer composition containing 1,4-DEHCH at a ratio of 40 to 80 parts by mass per 100 parts by mass of PVC. The further layer of foamed PVC plastisol may further contain a filler at a ratio of 70 to 200 parts by mass per 100 parts by mass of PVC.

[0026] To achieve the desired foaming, one or more blowing agents can be used. The blowing agent decomposes to generate gas (bubbles), causing foaming. Examples of known blowing agents include azodicarbonamide, carbonate, bicarbonate, or oxybisbenzenesulfonyl hydrazide (OBSH). Blowing agents are usually used in relatively small amounts. However, in principle, the amount of blowing agent correlates with the desired level of foaming. A further foamed layer derived from foamed PVC plastisol contains the blowing agent in a ratio of 2 to 5 parts by mass per 100 parts by mass of the blowing agent.

[0027] According to the present invention, the decomposition of the foaming agent can be catalyzed by a so-called kicker. The kicker used is generally a zinc-containing compound. Suitable kickers include, for example, ZnO, ZnBO3, and Zn salts, such as Zn octanoate, NaZn, KZn, or MgZn compounds. The kicker is usually used in small amounts, but its type and amount also have a significant effect on the rate of decomposition of the foaming agent, and therefore on the amount of bubbles formed in the time-limited foaming process, and thus causes foaming. Therefore, a further layer of foamed PVC plastisol may preferably contain the kicker in a ratio of 1 to 5 parts by mass per 100 parts by mass of PVC.

[0028] The further foamed layer derived from the foamed PVC plastisol may contain additives in addition to the above components. An example of such an additive is a rheological additive that can reduce the viscosity of the plastisol. Examples of rheological additives include products sold under the trade names VISCOBYK(registered trademark)-5120, VISCOBYK(registered trademark)-5130, and VISCOBYK(registered trademark)-4041. The additive may be present in the foamed PVC plastisol at a ratio of 4 to 10 parts by mass per 100 parts by mass of PVC.

[0029] In some cases, a further foam layer can be produced by mechanical foaming, i.e., agitation in air, instead of the chemical decomposition of the foaming agent. In this case, a so-called foam stabilizer, rather than a kicker agent or foaming agent, is added to the corresponding plastisol to prevent the introduced air from diffusing again, thereby preventing the collapse of the foam. Such compounds are usually silicone-based or soap-based and are known to those skilled in the art, for example, under the trade names "BYK® 8070" or "BYK® 8020". In a particularly preferred embodiment, this mechanical foam can also be used for impregnation of a carrier material.

[0030] In preferred embodiments of the present invention, the multilayer surface coating according to the present invention is decorated. Decoration in the context of the present invention means a visual and / or tactile configuration, for example, by the introduction of (printing) ink and / or embossing of a pattern. Such decoration can be applied and / or embossed on a layer derived from filler-containing PVC. However, it may be a further, optionally foamed decorative layer derived from PVC plastisol, on which decoration can be applied and / or embossed. The further, optionally foamed decorative layer derived from foamed PVC plastisol comprises, in particular, PVC, a plasticizer composition containing at least bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate, a filler, optionally a foaming agent, a kicker, and / or one or more additives.

[0031] In a particularly preferred embodiment of the present invention, the multilayer surface coating comprises at least one layer derived from a filler-containing PVC plastisol comprising a carrier material, PVC, a filler, and a plasticizer composition; at least one layer derived from a filler-free PVC plastisol comprising PVC and a plasticizer composition; and at least one foamed layer of a foamed PVC plastisol comprising PVC, a plasticizer composition, a filler, a foaming agent, and a kicker. Each plasticizer composition of the PVC plastisol used contains bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate (1,4-DEHCH). In a particularly preferred embodiment, the multilayer surface coating comprises a further scratch-resistant layer, preferably made of polyurethane or polyacrylate, and being transparent.

[0032] Preferably, the multilayer surface coating includes a further filler-containing layer, particularly a foamed layer, to which decoration is applied between a filler-free layer and a filler-containing layer. The decorative ink can be applied in one or more steps (individually for each color used), for example, using a screen printing drum. In this case, the principle of chemical inhibition is often used, but the printing ink may be a colored PVC plastisol and may contain an inhibitory solution that prevents or delays the decomposition of the foaming agent by chemically complexing the kicker at the site where it is applied to the layer, in which case foaming does not occur or occurs only slightly at that site. Suitable inhibitors, for example, benzotriazole or thiourea-based ones are commercially available.

[0033] The surface coating according to the present invention is preferably arranged in a specific sequence of layers. These arrangements of layers can also be seen in Figures 1, 2, and 3. In a basic embodiment (see Figure 1), the multilayer surface coating comprises at least one layer derived from a filler-containing PVC plastisol (2), which is preferably transparent, and at least one layer derived from a filler-free PVC plastisol (1). The at least one preferred transparent layer derived from the filler-free PVC plastisol (1) is positioned on top of the at least one layer derived from the filler-containing PVC plastisol (2).

[0034] Figure 2 shows a preferred embodiment in which, in addition to at least one preferred transparent layer derived from filler-free PVC plastisol (1) and at least one layer derived from filler-containing PVC plastisol (2), a carrier material (3) and a foamed layer derived from foamed PVC plastisol (4) are present. In this embodiment, the carrier material (3) is covered on both sides with filler-containing PVC plastisol and is therefore located within at least one layer derived from filler-containing PVC plastisol (2). Next, the foamed layer derived from foamed PVC plastisol (4) is placed below this layer (2). Alternatively, the carrier material may be covered only on its upper surface with filler-containing PVC plastisol. The carrier material is then directly adjacent to the foamed layer derived from foamed PVC plastisol (4).

[0035] Figure 3 shows a further preferred embodiment in which a further, optionally, foamed decorative layer (5) is present. This layer is then subjected to visual (color) and / or tactile decoration (e.g., embossing of a pattern) (6). Thus, the decorative layer (5) is positioned between at least one layer derived from filler-containing PVC plastisol (2) and at least one preferred transparent layer derived from filler-free PVC plastisol (1).

[0036] In a particularly preferred embodiment, a scratch-resistant layer, preferably polyurethane or polyacrylate, is applied to a preferably transparent layer derived from filler-free PVC plastisol to enhance scratch or abrasion resistance. This layer is not shown.

[0037] The multilayer surface coating according to the present invention can be manufactured by methods well known to those skilled in the art, by applying still-fluid plastisol layer by layer and optionally performing intermediate drying using a roller / gelling drum heated to, for example, about 100-140°C, to bring about gelation, i.e., incomplete gelation, so that the plastisols can be applied to the next layer without colliding with each other. Intermediate drying may be performed, for example, using a so-called gelling drum, i.e., a roller heated to a desired temperature.

[0038] Multilayer surface coatings can be used for a variety of applications. In a particularly preferred embodiment of the present invention, the surface coating is floor covering or artificial leather and is used for the corresponding application.

[0039] The present invention will be explained below with reference to examples. However, these examples are merely illustrative and should not be considered limiting. [Examples]

[0040] Plastisol manufacturing PVC plastisol was manufactured, for example, for the production of topcoat films (filler-free layers) for floor coverings. The amount of plastisol used is expressed as mass fraction (phr) in each case. The formulations are shown in Table 1. Table 1: Plastisol preparations

[0041] [Table 1] First, the liquid component and then the powder component were weighed and placed in a PE beaker. The mixture was manually stirred with a spatula until no unwetted powder remained in the mixture. The mixing beaker was then clamped to the clamping device of the dissolving stirrer. After switching on the stirrer, the speed was slowly increased to approximately 2000 rpm (revolutions per minute). Meanwhile, the plastisol was carefully degassed. For this purpose, the pressure was adjusted to less than 20 mbar. When the plastisol reached approximately 30°C, the rotation speed was reduced to approximately 350 rpm. The plastisol was then degassed at that speed for 9 minutes, and the pressure was reduced to less than 20 mbar. This confirmed that premature partial gelation did not occur during the homogenization of the plastisol.

[0042] The following plasticizers or mixtures of the following plasticizers were used in the plastisol: 1,4-DEHCH: Bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate (Invention, Hanwha Chemical Corp., South Korea) 1,2-DEHCH: Bis(2-ethylhexyl)cyclohexane-1,2-dicarboxylate (Nanya, Taiwan) DINP: Diisononyl phthalate (VESTINOL 9, manufactured by Evonik Operations GmbH) 1,2-DINCH: Diisononylcyclohexane-1,2-dicarboxylate (ELATUR CH, Evonik Operations GmbH) 1,4-DINCH: Diisononylcyclohexane-1,4-dicarboxylate (produced by cyclic hydrogenation of diisononyl terephthalate) DOTP: Dioctyl terephthalate (Eastman 168, Eastman, USA) DPT: Dipentyl terephthalate (Elatur DPT, Evonik Operations GmbH) 2088: Benzoflex 2088 (Glycol dibenzoate mixture, Eastman, USA) [Examples]

[0043] Measurement of plastisol viscosity The viscosity of the plastisol prepared in Example 1 was measured using a Physica MCR 101 rheometer (manufactured by Anton Paar Germany GmbH) with the associated software, in rotation mode and using the CC27 measurement system. The measurement was performed 24 hours after the plastisol was prepared and equilibrated at 25°C.

[0044] During the measurement, the following points were controlled: 60 seconds (100s) -1 Preliminary shear tests are performed, but measurements are not recorded during this period. Shear rate 200s -1 from 0.1s -1 The device was lowered to a certain point, and 30 measurement points were recorded, each with a measurement time of 10 seconds.

[0045] Measurements were performed at room temperature. In each case, the shear rate was 100 s. -1 The viscosity obtained was measured. Table 2 shows the results of viscosity measurements of the plastisol produced in Example 1 with the indicated plasticizer or plasticizer mixture. [Examples]

[0046] Gelation properties The gelation properties of the plastisol were investigated in vibration mode using a parallel plate analysis system (PP25) operating under shear stress control with Physica MCR 101 (Anton Paar). Furthermore, a temperature-controlled hood was connected to the system to achieve optimal thermal distribution. The following measurement parameters were set. mode: Temperature gradient (linear temperature gradient) Starting temperature: 25℃ End temperature: 180℃ Heating / cooling rate 5K / min Oscillation frequency: 4~0.1Hz Ramp (logarithmic) Cycle frequency omega: 10s -1 Measurement points: 63 Measurement duration: 0.5 minutes Automatic gap adjustment Constant measurement point interval Gap width: 0.5 mm Measurement procedure: A few drops of the plastisol to be measured were applied to the lower plate of the measurement plate using a spatula, ensuring that no air bubbles were present. After assembling the analysis system, it was confirmed that some of the plastisol could seep uniformly out of the analysis system (less than approximately 6 mm in any direction). Then, a temperature-controlled hood was placed over the sample, and the measurement was started. The so-called complex muscosity of the plastisol was measured as a function of temperature. The start of the gelation process can be recognized by a rapid increase in complex muscosity. The earlier this viscosity increase begins, the better the gelation ability of the system. From the obtained measurement curves, the temperature at which a complex muscosity of 1000 Pa*s was measured was determined for each plastisol using interpolation. The results are shown in Table 2. [Examples]

[0047] Film manufacturing The plastisols produced in Example 1 were each processed into 1 mm thick films.

[0048] Therefore, first, a high-gloss release paper (Sappi, Italy) was cut to a size of 30 x 44 cm and set on the stent frame of the Mathis oven LTSV coater. Then, the stent frame was placed on the guide frame, and the Mathis oven (LTF type) was set to 200°C and preheated after reaching this temperature. After that, the squeegee was set in the clamping device, and the squeegee gap was adjusted in a preliminary test so that the film thickness after gelation was 1 mm (±0.05 mm). Plastisol was spread onto the clamped release paper using the squeegee (speed 3 m / min). After that, the squeegee was removed and the stent frame was placed in the oven. After gelation (200°C, 2 minutes), the frame was removed from the oven, cooled, and the film was peeled off the paper. [Examples]

[0049] Cold flexibility due to glass transition temperature (DSC) For measurement, small circles (φ4.5 mm) were punched out from PVC films prepared from plastisol according to Example 4. These samples were analyzed under nitrogen in an aluminum crucible (perforated crucible lid) using a Mettler Toledo DSC 1 with the following settings: Dry nitrogen gas: Approximately 45 ml (STP) / min (= standard ml / min) Gas nitrogen (purge gas): Approximately 180 ml (STP) / min Cooling: Liquid nitrogen (1.5 bar auxiliary tank) method: [1] 25.0~120.0℃, 25.0K / min [2] Constant temperature method at 120.0°C for 5.00 minutes [3] 120.0℃ to -50.0℃, 25.0K / min [4] -50.0 to -120.0°C, 10.0K / min [5] Constant temperature method at -120.0°C for 3.00 minutes [6] -120 to 50.0°C, 10.0K / min Sync switch on Various temperature lamps eliminate the thermal history of the sample, thereby improving the reproducibility of the results. For the glass transition, the maximum peak value of the first derivative from the lamp [6] was evaluated. The obtained heat flux was plotted as a function of the measurement temperature. [Examples]

[0050] Volatility of plasticizers in film Three circles were punched out per sample from the PVC film manufactured in Example 4 using a punch (circular; 5 cm in diameter). The samples were equilibrated in a desiccator for 16 hours. The sample circle was weighed using an analytical balance, placed in a wire basket, and closed with a jaw clamp. 130 ml of activated carbon was placed in a tin can (1L tall). The first wire basket containing the sample was placed in the center of the activated carbon, and another 130 ml of activated carbon was added to the sample circle. 520 ml of activated carbon was placed in the tin can, and the sample was layered into three wire baskets. Finally, another layer of 130 ml of activated carbon was added. A lid with holes was placed over the can without applying pressure. The filled tin cans were placed in a temperature-controlled cabinet at 120°C, ensuring they did not obstruct the cabinet's fan or come into contact with each other. The air exchange and exhaust flaps were each set to 10%. After 72 hours at 120°C, the cans were removed from the cabinet and cooled. After cooling, individual samples were removed from the basket and allowed to rest in a desiccator for a further 16 hours before being weighed again on an analytical balance. The resulting mass difference was due to plasticizer loss. The average value was calculated from the three mass differences, and the amount of plasticizer loss was calculated as a percentage. The results are shown in Table 2. [Examples]

[0051] Measurement of Shore A hardness of a film Shore A hardness was measured by pouring plastisol, prepared in the same manner as in Example 1, into a round stainless steel mold with a diameter of 42 mm (initial weight: 20 g), and measuring the Shore A hardness. The paste was then placed in the mold and gelled in a circulating air drying oven at 200°C for 25 minutes. After cooling, it was removed and allowed to adjust in a climate chamber (25°C) for at least 16 hours before measurement. The thickness of the resulting specimen was approximately 12 mm. Hardness measurements were performed in accordance with DIN 53 505 using a Shore A hardness tester manufactured by Zwick-Roell, and the measurements were read after 3 seconds in all cases. Measurements were taken at three different locations on each test specimen, and the average value was calculated. The results are shown in Table 2. Table 2: Measurement results for Examples 2, 3, 5, 6, and 7

[0052] [Table 2] The results in Table 2 can be summarized as follows: The viscosity of the plasticizer 1,4-DEHCH according to the present invention is significantly lower than that of DINP. As a result, a higher packing density (more filler) can be achieved, and the use of viscosity reducers can be omitted. This is advantageous because it saves additional costs that would arise if viscosity reducers were used (e.g., the cost of the material, the cost of additional tanks for storing the material), and also avoids problems that may arise from the evaporation of viscosity reducers, which are usually highly volatile. Furthermore, the high efficiency due to the low Shore hardness can be utilized to conserve plasticizer and further reduce emissions. The glass transition temperature (Tg) of the film produced by Example 4 using 1,4-DEHCH as the plasticizer is equivalent to that of the film using DINP as the plasticizer. The 1,4-DEHCH according to the present invention exhibits the same gelation properties as DINP in Example 3, even without the addition of a fast gelling agent. Other plasticizers such as 1,2-DINCH, DOTP, and 1,4-DINCH can only be adjusted to have equivalent gelation properties if a fast gelling agent (in this case, DPT) is present. However, this increases volatility (Example 6), i.e., degradation occurs. 1,4-DINCH exhibits the lowest volatility, lowest viscosity, and best low-temperature flexibility (Example 5) among all the mixtures, but other properties such as gelation (Example 3) are clearly inferior. Here, it is necessary to consider the overall performance based on different parameters, rather than focusing on just one parameter. The plasticizer 1,4-DEHCH according to the present invention offers the best overall performance among all alternatives to DINP in terms of gelation, volatility, and efficiency (Shore hardness, viscosity, and low-temperature flexibility). Furthermore, it is advantageous because it does not require the addition of a fast gelling agent.

Claims

1. 1. A multi-layer surface coating, each layer comprising at least one layer derived from a filled PVC plastisol comprising PVC, a filler, and a plasticizer composition, and at least one layer derived from an unfilled PVC plastisol comprising PVC and a plasticizer composition, wherein the filled PVC plastisol and the plasticizer composition in the unfilled PVC plastisol each comprise bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate.

2. The multilayer surface coating described in claim 1, wherein the PVC in the filler-containing PVC plastisol and the filler-free PVC plastisol is, respectively, emulsion-type PVC, (micro)suspension-type PVC or a mixture thereof.

3. A multi-layer surface coating as described in claim 2, wherein the filler-free PVC plastisol comprises at least one emulsion type PVC and one (micro)suspension type PVC.

4. The multilayer surface coating of claim 1, wherein the filler-free PVC plastisol comprises a plasticizer composition in a ratio of 15 to 40 parts by weight per 100 parts by weight of PVC.

5. The multilayer surface coating of claim 1, wherein the filler-containing PVC plastisol comprises a plasticizer composition in a ratio of 35 to 80 parts by weight per 100 parts by weight of PVC.

6. The multilayer surface coating of claim 1, wherein the filler-containing PVC plastisol contains a filler in a ratio of 50 to 200 parts by weight per 100 parts by weight of PVC.

7. A multi-layer surface-coating according to any one of claims 1 to 6, comprising at least one carrier material, the filled PVC plastisol being coated on one or both sides with said carrier material.

8. The multi-layer surface coating of claim 7, wherein the carrier material comprises a polyester fabric, a glass non-woven fabric, paper or board.

9. A multi-layer surface-covering according to any one of claims 1 to 8, wherein on the reverse side of the surface-covering there is a further foamed layer derived from a foamable PVC plastisol.

10. 10. The multi-layer surface covering of claim 9, wherein the foamable PVC plastisol comprises PVC, a plasticizer composition, a filler, a foaming agent, and a kicker, and optionally a viscosity reducing additive.

11. 11. The multilayer surface-covering according to claim 9 or 10, wherein the further foamed layer derived from a foamable PVC plastisol comprises a filler in a proportion of 70 to 200 parts by weight per 100 parts by weight of PVC.

12. A multilayer surface-covering according to any one of claims 9 to 11, wherein the further foamed layer derived from a foamable PVC plastisol comprises a proportion of 40 to 80 parts by weight of plasticizer per 100 parts by weight of PVC.

13. 13. The multi-layer surface-coating according to any one of claims 9 to 12, comprising at least one layer from the filled PVC plastisol comprising the carrier material, PVC, a filler and a plasticizer composition, at least one layer from the unfilled PVC plastisol comprising PVC and a plasticizer composition, and at least one foamed layer from a foamable PVC plastisol comprising PVC, a plasticizer composition, a filler, a foaming agent, a kicker, where the plasticizer composition comprises bis(2-ethylhexyl)cyclohexane-1,4-dicarboxylate in all used PVC plastisols.

14. 14. The multi-layer surface coating of claim 13, further comprising a scratch resistant layer and is transparent.

15. The multi-layer surface coating of claim 14, wherein the scratch-resistant layer comprises a polyurethane or a polyacrylate.

16. Use of the multilayer surface coating according to any one of claims 1 to 15 as a floor covering or artificial leather.

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