Artificial marble and its manufacturing method

Abstract

To provide a technique that can reduce the weight of artificial marble while preventing its hardness from decreasing.SOLUTION: Artificial marble disclosed herein has a design layer, a substrate layer containing a plurality of balloons, and an intermediate layer lying between the design layer and the substrate layer, the intermediate layer having a different composition from those of the design layer and the substrate layer.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The technology disclosed in this specification relates to artificial marble and its manufacturing method.

Background Art

[0002] Patent Document 1 discloses a technology of blending glass micro hollow spheres into a resin composition for weight reduction of artificial marble.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the above artificial marble contains micro hollow spheres, its hardness may decrease. This specification provides a technology for preventing the decrease in hardness while realizing weight reduction of artificial marble. <0​​​​​​​​​A method for manufacturing artificial marble disclosed herein comprises a design layer, a base layer containing a plurality of balloons, and an intermediate layer located between the design layer and the base layer, wherein a first material for forming the design layer is applied to the surface of a mold, a second material for forming the intermediate layer, having a different composition from the first material, is applied on top of the first material, and after the first and second steps, a third material for forming the base layer, containing the plurality of balloons, is poured into the mold. [Brief explanation of the drawing]

[0007] [Figure 1] A cross-sectional view showing the composition of artificial marble. [Figure 2] Enlarged view of Part II in Figure 1. [Figure 3] A schematic flowchart illustrating the manufacturing method of artificial marble. [Figure 4] A table showing the results of performance evaluation tests. [Figure 5] A table showing the results of the thick-film coating performance test. [Modes for carrying out the invention]

[0008] (Composition of artificial marble: Figures 1 and 2) The structure of the artificial marble 10 will be described with reference to Figures 1 and 2. The artificial marble 10 is used in residential equipment such as washbasins, kitchen counters, and bathtubs. As shown in Figure 1, the artificial marble 10 comprises a design layer 12, an intermediate layer 14, and a base layer 16. In this embodiment, the artificial marble 10 is characterized by comprising an intermediate layer 14 having a different composition from the design layer 12 and the base layer 16.

[0009] In this embodiment, the thickness of the design layer 12 is, for example, 0.30 to 0.60 mm. The design layer 12 has a design surface 12a located on the uppermost surface of the artificial marble 10. Therefore, when the artificial marble 10 is used in residential equipment, the user will see the design surface 12a. The design layer 12 is made of a resin material. In this embodiment, the resin material is a thermosetting resin, specifically an unsaturated polyester resin. In a modified example, the resin material may be other materials such as vinyl ester resin, epoxy resin, or acrylic resin. In another modified example, the resin material may be a resin material different from the thermosetting resin (for example, urethane resin, acrylic urethane resin, etc.).

[0010] In this embodiment, the thickness of the base layer 16 is, for example, 10 mm or more. The upper limit of the thickness of the base layer 16 is not particularly limited. Considering strength and moldability, the upper limit of the thickness of the base layer 16 is preferably 30 mm or less. If moldability is given more importance, 25 mm or less, and even more preferably 20 mm or less, is preferred. The base layer 16 is made of a resin material. In this embodiment, the resin material is a thermosetting resin, specifically an unsaturated polyester resin. In a modified example, the resin material may be other materials such as vinyl ester resin, epoxy resin, or acrylic resin. In another modified example, the resin material may be a resin material different from the thermosetting resin (e.g., urethane resin). As shown in Figure 2, the base layer 16 includes a plurality of balloons 18. The balloons 18 are spherical hollow bodies. The balloons 18 are made of an organic material. In this embodiment, the balloons 18 are resin balloons. In a modified example, the balloons 18 may be made of an inorganic material such as a ceramic balloon.

[0011] When the base layer 16 contains balloons 18, the density of the base layer 16 is lower compared to when the base layer 16 does not contain balloons 18, making it possible to realize a lightweight artificial marble 10. The density of the base layer 16 can be adjusted by the mixing ratio of balloons 18. To achieve weight reduction, the density of the base layer 16 should be 1.5 g / cm³. 3 Preferably, the following, and in this embodiment, 0.5 g / cm³ 3In a modified example, the density of the base layer 16 is 1.5 g / cm³. 3 It can be even larger, for example, 1.7 g / cm³ 3 That's fine.

[0012] The balloon 18 has a layer of gas inside. This reduces the thermal conductivity of the base layer 16, increasing the thermal insulation of the artificial marble 10. High thermal insulation of the artificial marble 10 can prevent users from feeling that the artificial marble 10 is cold when they come into contact with it, for example, in winter. The thermal conductivity of the base layer 16 can be adjusted by the mixing ratio of the balloon 18. In order to achieve thermal insulation that can prevent users from feeling uncomfortable, the thermal conductivity of the base layer 16 is preferably 1 W / m·K or less, and in this embodiment it is 0.11 W / m·K. In a modified example, the thermal conductivity of the base layer 16 may be greater than 1 W / m·K, for example, 1.1 W / m·K.

[0013] The intermediate layer 14 is located between the design layer 12 and the base layer 16. The intermediate layer 14 is made of a resin material. In this embodiment, the resin material is a thermosetting resin, specifically an unsaturated polyester resin. In a modified example, the resin material may be other materials such as vinyl ester resin, epoxy resin, or acrylic resin. In another modified example, the resin material may be a resin material different from the thermosetting resin (e.g., urethane resin). As shown in Figure 2, the intermediate layer 14 does not contain balloons 18 but contains glass fibers 20. Therefore, the intermediate layer 14 has a different composition from the design layer 12, which does not contain glass fibers 20, and also a different composition from the base layer 16, which contains balloons 18. In a modified example, the intermediate layer 14 may contain organic fibers such as polyester or vinylon instead of glass fibers 20. In this embodiment, the length of one glass fiber 20 is approximately 200 μm.

[0014] The intermediate layer 14 is formed, for example, by spray coating. The glass fibers 20 function as a sagging prevention material when the intermediate layer 14 is formed in this manner. In other words, the glass fibers 20 function as a viscoelastic modifier during the formation of the intermediate layer 14. The glass fibers 20 also function as a shrinkage inhibitor during the formation of the intermediate layer 14. Specifically, when the spray-coated wet film hardens and shrinks, the glass fibers 20 can suppress the shrinkage of the film. As a result, the occurrence of wrinkles in the film after hardening can be suppressed. In modified examples, the intermediate layer 14 may not contain a sagging prevention material or a shrinkage inhibitor. The intermediate layer 14 may also contain other materials different from the sagging prevention material and the shrinkage inhibitor.

[0015] The thickness of the intermediate layer 14 will now be described. In this embodiment, the thickness of the intermediate layer 14 is 0.8 mm. Preferably, the thickness of the intermediate layer 14 is 0.1 mm or more. With such a thickness, a decrease in the hardness of the artificial marble 10 is prevented. More preferably, the thickness of the intermediate layer 14 is 0.3 mm or more. With such a thickness, the drop resistance of the artificial marble 10 is sufficiently maintained. More preferably, the thickness of the intermediate layer 14 is 0.5 mm or more. With such a thickness, it is possible to form an intermediate layer 14 with little variation in thickness. The thickness of the intermediate layer 14 is preferably 1.1 mm or less. With such a thickness, sagging during the formation of the intermediate layer 14 can be suppressed. In a modified example, the thickness of the intermediate layer 14 may be less than 0.1 mm, for example, 0.05 mm. In another modified example, the thickness of the intermediate layer 14 may be greater than 1.1 mm, for example, 0.12 mm.

[0016] As described above, the artificial marble 10 includes a base material layer 16 containing a plurality of balloons 18. Therefore, the weight of the artificial marble 10 can be reduced. However, when the base material layer 16 contains balloons 18, the hardness of the artificial marble 10 decreases. To prevent this, the artificial marble 10 of the present embodiment further includes an intermediate layer 14 having a composition different from that of the design layer 12 and the base material layer 16 between the design layer 12 and the base material layer 16. Therefore, compared with the artificial marble composed only of the design layer 12 and the base material layer 16, the artificial marble 10 with a reduced hardness can be realized.

[0017] (Method for manufacturing artificial marble 10: Fig. 3) Referring to Fig. 3, the method for manufacturing the artificial marble 10 will be described. The materials for forming the design layer 12, the intermediate layer 14, and the base material layer 16 are resin mixtures X, Y, and Z, respectively. The details of X, Y, and Z will be described in the following examples.

[0018] First, as shown in the upper figure of Fig. 3, a mold 22 is prepared and the first spraying process is executed. In the first spraying process, in a state where the surface 22a of the mold 22 extends in the vertical direction, the resin mixture X, which is the material constituting the design layer 12, is applied to the surface 22a by a spray gun G1. When the wet film of the resin mixture X applied to the mold 22 hardens, the design layer 12 is formed.

[0019] As shown in the central figure of Fig. 3, after the first spraying process, the second spraying process is executed. In the second spraying process, in a state where the surface 22a of the mold 22 extends in the vertical direction, the resin mixture Y, which is the material constituting the intermediate layer 14, is applied onto the design layer 12 by a spray gun G2. When the wet film of the resin mixture Y applied onto the design layer 12 hardens, the intermediate layer 14 is formed.

[0020] As shown in the lower figure of FIG. 3, after the second spraying step, a casting step is performed. In the casting step, a resin mixture Z, which is the material constituting the base material layer 16, is poured into a mold 22 with the surface on which the design layer 12 and the intermediate layer 14 are formed as the bottom surface. When the poured resin mixture Z cures, the base material layer 16 is formed. Then, when the design layer 12, the intermediate layer 14, and the base material layer 16 are removed from the mold 22, the artificial marble 10 is completed.

[0021] (Example) An example will be described. The resin mixture X, which is the material constituting the design layer 12, is obtained by adding 0.5 to 2 parts by weight of methyl ethyl ketone peroxide as a curing agent to 100 parts by weight of unsaturated polyester. The resin mixture Y, which is the material constituting the intermediate layer 14, is obtained by adding a trace amount of a mixture of methyl ethyl ketone peroxide and dimethyl phthalate as a curing agent to the main agent. The main agent contains 80 parts by weight of unsaturated polyester, 17 to 19 parts by weight of glass fiber having a length of about 200 μm, and a trace amount of cobalt octenoate, and specifically, is "MF-A Main Agent #6978" manufactured by Daitai Chemical Industry Co., Ltd. The resin mixture Z, which is the material constituting the base material layer 16, is obtained by adding 0.5 to 2 parts by weight of methyl ethyl ketone peroxide as a curing agent to 100 parts by weight of unsaturated polyester and 15 parts by weight of resin balloons (EMC-80(B) manufactured by Nippon Filight Co., Ltd.).

[0022] By the manufacturing method shown in FIG. 3, the artificial marble 10 was formed from the resin mixtures X, Y, and Z. As a result, an artificial marble 10 having a density of the base material layer 16 of 0.5 g / cm 3 and a thermal conductivity of the base material layer 16 of 0.11 W / m·K was obtained.

[0023] In the first and second spraying processes, the air pressure of the spray gun was 0.15 MPa. Samples 1 to 4 were formed, each with the same thickness of design layer 12 (for example, approximately 0.35 mm) and different thicknesses of the intermediate layer 14. The following performance evaluation tests were then conducted. The thicknesses of the intermediate layer 14 in samples 1, 2, 3, and 4 were 0.1, 0.3, 0.5, and 0.8 mm, respectively.

[0024] As Comparative Example 1, an artificial marble without the intermediate layer 14 was formed. The design layer and base layer of Comparative Example 1 were formed under the same conditions as in the Examples. Then, a performance evaluation test was performed on the artificial marble of Comparative Example 1 in the same manner as in the Examples.

[0025] (Performance evaluation test: Figure 4) As shown in Figure 4, the performance evaluation test evaluates the hardness, drop resistance, and coating stability of the artificial marble 10 and the intermediate layer 14. Tests that meet the evaluation criteria are indicated with "○ (i.e., good)", and tests that do not meet the evaluation criteria are indicated with "× (i.e., poor)".

[0026] The hardness of the artificial marble 10 was evaluated by measuring the Barcol hardness of the surface of the sample (i.e., the design surface 12a) using a Barcol hardness tester. A Barcol hardness of 40 or higher was set as the evaluation criterion. In Comparative Example 1, the Barcol hardness was 0 (i.e., the hardness evaluation was "×"). In Samples 1 to 4, the Barcol hardness was 40 or higher (i.e., the hardness evaluation was "〇"). From this, it was confirmed that even when the base layer 16 contains multiple balloons 18, the hardness (i.e., surface hardness) of the artificial marble 10 can be improved if an intermediate layer 14 with a thickness of 0.1 mm or more is provided.

[0027] The drop durability was evaluated by observing the diameter of the indentation and the surface condition resulting from dropping a steel ball onto the decorative layer of artificial marble. The dimensions of the decorative layer were 100 mm x 100 mm. The diameter and mass of the steel ball were 19 mm and 28.1 g, respectively. The drop height of the steel ball was 700 mm. The evaluation criteria were set as an indentation diameter of 3 mm or less and no cracks or delamination on the decorative surface. No cracks or delamination were observed in Comparative Example 1 and Sample 1. However, the indentation diameter was greater than 3 mm in Comparative Example 1 and Sample 1 (i.e., the drop durability evaluation was "×"). In Samples 2-4, there were no cracks or delamination, and the indentation diameter was 3 mm or less (i.e., the drop durability evaluation was "〇"). From this, it was confirmed that if the thickness of the intermediate layer 14 is 0.3 mm or more, drop durability that meets the product standard can be ensured.

[0028] The coating stability of the intermediate layer 14 was evaluated by observing images of the cross-sectional structure of the artificial marble 10 using an electron microscope. The evaluation criterion was set as follows: the surface irregularities between the intermediate layer 14 and the substrate layer 16 should not be noticeable when visually inspecting the observed images. In samples 1 and 2, the thickness of the intermediate layer 14 was not uniform, and irregularities were noticeable (i.e., the coating stability evaluation was "×"). In samples 3 and 4, the thickness of the intermediate layer 14 was uniform, and irregularities were not noticeable (i.e., the coating stability evaluation was "〇"). From this, it was confirmed that the coating stability of the intermediate layer 14 can be improved if the thickness of the intermediate layer 14 is 0.5 mm or more. The reason why coating stability improves with increasing film thickness lies in the liquid properties of the resin material used in the intermediate layer 14. Due to the inclusion of glass fibers for functionalization, the droplet size of the spray coating becomes coarser, so a film thickness of 0.5 mm or more is necessary for a smooth coated surface.

[0029] (Thick film coating performance test: Figure 5) Next, as shown in Figure 5, the thick-film coating properties of the intermediate layer 14 of the example were evaluated. In the thick-film coating properties test, the material constituting the intermediate layer 14 (i.e., the resin mixture Y of the example) was applied to the surface of the mold using a spray gun to form an intermediate layer 14 of a predetermined thickness on its own. At this time, the mold was set up so that the surface extended in the vertical direction, and the resin mixture Y was applied to the surface from a direction perpendicular to the surface using a spray gun. The spray application conditions were an air pressure of 0.15 MPa and a distance of 300 mm between the surface of the mold and the spray gun.

[0030] In this test, multiple intermediate layers 14 with different thicknesses were formed, with film thicknesses of 0.3, 0.5, 0.7, 0.9, 1.1, and 1.3 mm. The film thicknesses are those of the uncured film immediately after deposition. At each film thickness, it was checked whether or not sagging of the resin mixture Y occurred. In Figure 5, "○" indicates that no sagging occurred at each film thickness, and "×" indicates that sagging occurred.

[0031] Comparative Example 2 in Figure 5 shows the test results when resin mixture X from the example was used instead of resin mixture Y. In other words, the material of Comparative Example 2 is approximately equivalent to resin mixture Y with the glass fibers removed.

[0032] In the embodiment, no sagging occurred when the thickness of the intermediate layer 14 was 0.3 to 1.1 mm (i.e., evaluation "○"), but sagging occurred when the thickness of the intermediate layer 14 was 1.3 mm (i.e., evaluation "×"). From this, it was confirmed that if the thickness of the intermediate layer 14 is 1.1 mm or less, sagging does not occur during spray coating, and an intermediate layer 14 with a constant thickness can be formed.

[0033] In Comparative Example 2, no sagging occurred when the thickness of the intermediate layer was 0.3 to 0.7 mm (i.e., evaluation "○"), but sagging occurred when the thickness of the intermediate layer was 0.9 mm (i.e., evaluation "×"). From the above, it was confirmed that in the example, sagging was less likely to occur even when the thickness of the intermediate layer 14 was greater than in Comparative Example 2, and that it had excellent thick-film coating properties. In other words, the inclusion of glass fibers 20 in the intermediate layer 14 suppressed sagging when the intermediate layer 14 was formed.

[0034] The above describes in detail specific examples of the technology disclosed herein. These are merely illustrative examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples described above. The following are some examples of modifications.

[0035] (Modification 1) The structure of the artificial marble 10 is not limited to the three-layer structure of the above embodiment. For example, the artificial marble 10 may have another layer between the design layer 12 and the intermediate layer 14, or another layer between the intermediate layer 14 and the base layer 16.

[0036] (Modification 2) The method for manufacturing the artificial marble 10 is not limited to the above embodiment. It may include a step of forming another layer between the first spraying step and the second spraying step, or a step of forming another layer between the second spraying step and the casting step.

[0037] (Modification 3) In the above embodiment, the resin materials constituting the design layer 12, the intermediate layer 14, and the base layer 16 are the same unsaturated polyester resin. Alternatively, the resin materials constituting the design layer 12, the intermediate layer 14, and the base layer 16 may be different resin materials.

[0038] The technical elements described herein and in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technologies illustrated herein and in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of symbols]

[0039] 10: Artificial marble, 12: Design layer, 14: Intermediate layer, 16: Base layer, 18: Balloon, 20: Glass fiber, 22: Mold, 22a: Surface

Claims

1. Design layer and, A substrate layer containing multiple balloons, An intermediate layer located between the design layer and the base material layer, which does not contain balloons but contains glass fibers, comprising: The thickness of the aforementioned intermediate layer is 0.1 mm or more and 1.1 mm or less. Artificial marble, wherein the design layer, the base layer, and the intermediate layer are each composed of an unsaturated polyester resin.

2. The artificial marble according to claim 1, wherein the balloon includes a resin balloon.

3. The artificial marble according to claim 1 or 2, wherein the glass fibers function as a sagging prevention material.

4. The artificial marble according to any one of claims 1 to 3, wherein the glass fibers function as a shrinkage inhibitor.

5. The artificial marble according to any one of claims 1 to 4, wherein the thickness of the intermediate layer is 0.3 mm or more.

6. The artificial marble according to any one of claims 1 to 5, wherein the thickness of the intermediate layer is 0.5 mm or more.

7. The artificial marble according to any one of claims 1 to 6, wherein the thermal conductivity of the base material layer is 1 W / m·K or less.

8. The density of the substrate layer is 1.5 g / cm³. 3 The artificial marble according to any one of claims 1 to 7, which is as follows:

9. A method for manufacturing artificial marble comprising a design layer, a base layer containing a plurality of balloons, and an intermediate layer located between the design layer and the base layer, which does not contain balloons but contains glass fibers, The aforementioned manufacturing method is A first material for forming the design layer is applied to the surface of the mold. A second material for forming the intermediate layer, wherein the second material is applied on the first material. A third material for forming the base layer, wherein the third material including the plurality of balloons is poured into the mold. The thickness of the aforementioned intermediate layer is 0.1 mm or more and 1.1 mm or less. A manufacturing method wherein the design layer, the base material layer, and the intermediate layer are each composed of an unsaturated polyester resin.

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