Whisker enhanced light-transmitting artificial stone and preparation method thereof

Abstract

The invention discloses a whisker enhanced light-transmitting artificial stone and a preparation method thereof. The artificial stone consists of 55-75wt% of anhydrous calcium sulfate whiskers, 35-45wt% of unsaturated resin and a curing agent, and has the innovation points that: a) the special whiskers with unique axial sub-wavelength cylindrical bulges (with the width of 50-200nm) are adopted, so that light scattering is effectively reduced; b) forming a gradient refractive index interface by accurately regulating and controlling the refractive index (1.59) of the whisker and the refractive index (1.57) of the resin until the difference value is less than or equal to 0.02; and c) optimizing the optical performance by adopting an orthophthalic resin system added with 10-25% of MMA monomer. The crystal whiskers form an interlocking network in a matrix through a stepped mixing and vacuum vibration exhaust curing process, finally, the high light transmittance of 30%-40% of a plate with the thickness of 20 mm under the wavelength of 550 nm is achieved, and the standard deviation of light transmittance uniformity is smaller than or equal to 5%. The product is particularly suitable for the field of high-end building light-transmitting decoration, the uniform light-transmitting effect under the ultra-short light source hiding distance smaller than or equal to 50 mm can be achieved, and the technical problems that the thickness of a traditional light-transmitting stone is limited, and a light source is difficult to hide are solved.

Description

Technical Field

[0001] This invention relates to the field of functional building decoration materials technology, specifically to a whisker-reinforced artificial stone with light transmittance and high uniformity, its preparation method, and its application. Background Technology

[0002] Artificial translucent stone, as a high-end decorative material, is typically composed of resin as a matrix, mineral powder, or special functional fillers. Through specific processes, it is endowed with excellent light transmission capabilities (some products can achieve a light transmittance of over 85%). This type of material combines the aesthetic texture and lightweight characteristics of natural stone (weighing approximately one-quarter of natural stone) with good workability (such as hot bending). It is mainly used in high-end commercial spaces (such as translucent background walls in hotels and illuminated counters in luxury stores) and customized home furnishings (translucent ceilings, artistic lampshades). According to data from the China Building Materials Federation (2023), its market demand has grown at an average annual rate of 12%. Although artificial translucent stone possesses a unique translucent visual effect and flexible workability, its development is still limited by its complex production process, high raw material costs, and relatively lower surface hardness compared to quartz stone.

[0003] The key to achieving high-performance light transmission lies in the selection and design of fillers. Traditional mineral powder fillers face significant challenges in light transmission applications: insufficient matching between their refractive index and the resin matrix can easily lead to interfacial scattering losses; irregular shapes and wide particle size distributions can exacerbate light path disturbances; and it is difficult to maintain uniform dispersion and stable structure at high filling ratios, ultimately limiting light transmittance and uniformity.

[0004] Whisker materials (such as the anhydrous calcium sulfate whiskers used in the core of this patent) have shown unique potential as a type of high-performance reinforcing / functional filler in solving the aforementioned light transmission bottlenecks:

[0005] (1) Excellent axial light guiding properties: Its high aspect ratio (e.g., 30-80) and regular single crystal structure provide better axial light transmission capability and reduce lateral scattering.

[0006] (2) Potential for precise refractive index control: The intrinsic refractive index of certain types of whiskers (such as anhydrous calcium sulfate crystals ≈1.59) is very small (≤ 0.02) compared with that of commonly used resins (≈ 1.57), providing an ideal basis for achieving a gradient refractive index interface with low scattering and high light transmittance.

[0007] (3) Advantages of structural ordering: Whiskers can easily form an interlocked stacked three-dimensional network structure in the matrix through specific processes, which not only improves mechanical properties, but also builds an ordered light transmission channel and optimizes light transmission uniformity.

[0008] (4) Surface morphology designability: By specifically modifying the whisker surface (such as forming a subwavelength structure), the behavior of light at the interface can be further controlled, thereby enhancing the light coupling efficiency.

[0009] Therefore, developing new translucent artificial stone based on high-performance whisker fillers and designing matching precision manufacturing processes are key directions for breaking through existing technological limitations and achieving higher performance (especially high uniformity of light transmission and good mechanical properties) translucent decorative materials.

[0010] The optical properties of translucent artificial stone, especially its transmittance and uniformity, primarily depend on the refractive index matching between the filler and the resin matrix. When light passes through the interface of two media with different refractive indices, significant Fresnel reflection and scattering occur, leading to light energy loss and optical path disruption. The refractive indices of mineral powder fillers (such as aluminum hydroxide and quartz powder) used in traditional translucent stone are typically in the range of 1.48-1.55 or 1.54-1.56, which differs significantly from commonly used unsaturated resins (refractive index ≈ 1.57) (the difference is often greater than 0.05). This mismatch creates strong scattering centers at numerous filler-resin interfaces, severely reducing the overall transmittance of the material and causing uneven light distribution (resulting in "white spots" or "dark areas"), especially when the thickness increases or the filler ratio rises.

[0011] This invention creatively selects anhydrous calcium sulfate whiskers (CaSO4) as the core light-transmitting filler. Its core optical advantage lies in the extremely close proximity of its intrinsic refractive index (≈ 1.59) to that of the selected unsaturated resin matrix (≈ 1.57), with the difference strictly controlled within a very small range of ≤ 0.02 (preferably ≤ 0.015). This near-matched refractive index relationship fundamentally and significantly reduces the intensity of light reflection and scattering at the whisker-resin interface. Theoretical calculations and experiments both show that when the refractive index difference between the two media is less than 0.03, Fresnel reflection loss at the interface can be reduced to an extremely low level, and scattering effects are also significantly suppressed, laying a key physical foundation for constructing high-transmittance composite materials.

[0012] The deeper innovation of this invention, going beyond simple refractive index matching, lies in inducing the formation of a "Graded Refractive Index Interface" (GRIN) and an interlocking stacked three-dimensional network structure with optically graded refractive index characteristics between the surface of anhydrous calcium sulfate whiskers and the resin matrix through specific process control (see the preparation method section for details). The formation mechanism of this structure mainly involves:

[0013] (1) Molecular-level wetting and interdiffusion: During the step mixing stage (especially the triggering step at 60 °C and 90 rpm), the resin monomer / oligomer molecules deeply wet the surface of the whiskers under the action of heat and shear force, and partially interdiffusion occurs with the extremely thin adsorption layer or modified groups that may exist on the surface of the whiskers.

[0014] (2) Synergistic effect of subwavelength structure: The inherent axially extending subwavelength cylindrical protrusions (50-200 nm wide) on the whisker surface provide nanoscale anchors for the resin. Simultaneously, their size is much smaller than the visible light wavelength (380-780 nm), causing light to pass through this microstructure region not at a sudden transition from the whisker (n = 1.59) to the resin (n = 1.57), but rather through a gradual transition in refractive index from close to 1.59 to close to 1.57. This gradual transition further reduces the effective refractive index difference at the whisker-resin interface to near zero. Light passing through this gradient layer follows a smoother path, and the scattering cross-section is greatly compressed.

[0015] (3) The interlocked stacked three-dimensional network structure formed is the core structure for realizing the excellent comprehensive performance of this invention. A large number of relatively continuous, low-torsion "light guiding channels" are constructed. Light can be transmitted efficiently and orderly along the whisker axis and through the low-loss path formed by the close contact points between whiskers.

[0016] In translucent composite materials, the spatial distribution of fillers has a decisive influence on optical and mechanical properties. Traditional mineral powder fillers, due to their irregular shapes, low aspect ratios, and smooth surfaces, are prone to agglomeration, sedimentation, or random disordered stacking at high filler concentrations. This disordered structure leads to: severe light scattering centers: agglomerates and filler contact points form numerous interfaces with significantly different refractive indices from the resin, generating strong Mie scattering, significantly reducing transmittance and disrupting uniformity; blocked light transmission paths: disordered stacking creates numerous dead ends and tortuous paths, hindering effective light penetration, especially with a sharp decrease in transmittance as thickness increases; and mechanical performance bottlenecks: the lack of effective connections between fillers means that stress is mainly transferred through the resin, making it difficult to achieve high strength and high toughness.

[0017] The anhydrous calcium sulfate whiskers selected in this invention, with their unique aspect ratio (30-80) and the axially extending subwavelength cylindrical protrusions on the surface as described in feature (a) of claim 1, provide an ideal foundation for solving the aforementioned challenges: High aspect ratio (30-80): endows the whiskers with excellent geometric interlocking ability. Compared to short fibers or particles, long whiskers are more likely to cross greater distances, contacting and intertwining with each other; Subwavelength protrusions on the surface (50-200 nm wide): these protrusions are not smooth surfaces, but provide nanoscale mechanical interlocking points. When whiskers approach or contact each other, the protrusions can effectively "hook" adjacent whiskers, resisting relative slippage and significantly enhancing the bonding force between whiskers. This "micromechanical interlocking" mechanism is key to forming a stable three-dimensional network; Rigid single-crystal structure: ensures that the whiskers are not easily bent or deformed during processing and under stress, maintaining the stability of the network skeleton.

[0018] The precision fabrication process described in claim 3, particularly the vacuum vibration degassing stage, is the key driving force for inducing the oriented arrangement of whiskers and achieving effective interlocking stacking to form a three-dimensional network: Stage 1 vibration (25 ~ 40 ℃, 30 – 50 Hz, 0.2 - 0.4 mm amplitude): The high-frequency, large-amplitude vibration in this stage mainly plays the following role:

[0019] (1) Powerful agglomeration breaking: High energy input effectively breaks down whisker pre-agglomerates.

[0020] (2) Promote uniform dispersion: make the whiskers fully dispersed in the resin with relatively low viscosity.

[0021] (3) Inducing preliminary orientation: The vibration shear force field causes whiskers with large aspect ratios to align to a certain extent along the vibration direction or shear plane, reducing random crossing.

[0022] (4) Stage 2 vibration (55 ~ 65 ℃, 10 – 20 Hz, 0.05 - 0.1 mm amplitude): The low-frequency, micro-amplitude vibration in this stage is more refined. The lower energy input avoids damaging the initial structure or inducing turbulence. The gentler vibration encourages the whiskers to achieve precise interlocking (rather than simple physical contact) at closer positions through the "hooking" effect of surface subwavelength protrusions. Under the condition that the resin viscosity is appropriately reduced due to the increase in temperature, the vibration helps to fine-tune the whisker network structure, eliminate local stress concentration points, and form a more uniform and more interconnected three-dimensional skeleton. Micro-amplitude vibration helps to remove the tiny air bubbles remaining in the network gaps. At the same time, the resin is better "wetted" and filled in the micro-space around the whisker interlocking points under vibration, solidifying the connection between the whiskers.

[0023] One of the core microscopic features of the anhydrous calcium sulfate whiskers described in this invention is that their surface has axially extending subwavelength cylindrical protrusions (claim 1(a)). Specifically:

[0024] Morphological characteristics: The protrusions are cylindrical and extend strictly along the axial direction of the whisker (not randomly or radially distributed). This directional arrangement is highly consistent with the axial crystal structure and light transmission direction of the whisker itself.

[0025] Scale characteristics: average width: 50 - 200 nm; average height: 20 - 100 nm; coverage: the protrusions have a complete coverage of ≥ 90% on the whisker surface (especially the side surface) (claim 2), ensuring the universality of the effect.

[0026] The characteristic dimensions (width and height) of the protrusions are significantly smaller than the visible light wavelength range (380–780 nm), which is a key prerequisite for their unique optical modulation function. The protrusion dimensions (width 50–200 nm, height 20–100 nm) are much smaller than the visible light wavelength, causing their scattering behavior to fall into the Rayleigh scattering or even weaker quasi-static scattering region. In this region, the scattering intensity is proportional to the sixth power of the particle size. Therefore, controlling the characteristic dimensions within the subwavelength range (especially ≤ 200 nm) can suppress scattering loss to an extremely low level.

[0027] The stability and strength of the "interlocked stacked" three-dimensional network structure described in claim 1(c) are highly dependent on these subwavelength protrusions on the whisker surface (claim 2). The cylindrical shape and height of the protrusions (20–100 nm) form dense nanoscale "hooking points" on the whisker surface, providing nanoscale anchoring points. When two whiskers approach and come into contact with each other under vibration (especially the low-frequency micro-vibration of stage 2 in claim 3(b)), the protrusions on their surfaces can interlock and hook with each other, achieving "micromechanical interlocking." This effect significantly increases the friction coefficient between whiskers, effectively resisting relative slippage of whiskers under stress (such as tension or shear). It transforms the simple physical contact of point or line contact into microscopic interlocking nodes with significant load-bearing capacity, providing direct mechanical engagement. A large number of such interlocking nodes are distributed throughout the three-dimensional network, greatly enhancing the overall stiffness and stability of the network. This enables the network to effectively resist resin curing shrinkage stress, external loads, and disturbances during processing even at high filler contents (55 ~ 75 wt%), ensuring structural integrity and dimensional accuracy of the final product.

[0028] This light-force synergistic mechanism is the core microscopic innovation of the present invention, which enables the whisker-shaped translucent artificial stone to simultaneously achieve high light transmittance, high uniformity, high filling capacity, and excellent mechanical properties.

[0029] Currently, high-end artificial translucent stone generally uses high-purity mineral powders (such as aluminum hydroxide and quartz powder) as the main filler, combined with a transparent resin matrix (such as unsaturated polyester resin), and is prepared through casting, vibration venting, and thermosetting processes. Although such products can claim high light transmittance (>85%) for thin sheets (e.g., ≤ 5 mm thickness) or low filler ratios, in practical engineering applications, especially when pursuing high optical uniformity, high light transmittance over large thicknesses, and comprehensive performance, they suffer from the following inherent defects that are difficult to overcome:

[0030] (1) Severe refractive index mismatch and interface scattering:

[0031] The refractive index of mineral powder fillers (e.g., aluminum hydroxide: ≈ 1.57 - 1.59, quartz powder: ≈ 1.54 - 1.56) is insufficiently matched with that of commonly used resins (≈ 1.57) (the difference Δn is often > 0.05). The filler-resin interface exhibits an abrupt change in refractive index, leading to significant Fresnel reflection and Mie scattering. With increasing thickness (> 10 mm) or filling ratio (> 50 wt%), light transmittance decreases sharply (e.g., typically < 15% for a 20 mm thickness), and light distribution becomes uneven (distinct "white haze" or "bright spots"), with a uniformity standard deviation often > 15%.

[0032] (2) Packing morphology and structural defects:

[0033] The mineral powder has an irregular shape, low aspect ratio (close to 1:1), and smooth surface. Under high filling conditions, it is prone to disordered accumulation and agglomeration, forming numerous scattering centers and optical path blockage points. It is impossible to construct long-range ordered optical transmission channels or effective carrier networks. It is difficult to achieve high filling, high light transmittance, and high uniformity simultaneously.

[0034] (3) Process complexity and performance bottlenecks:

[0035] To achieve high light transmittance, ultrafine powders (such as nano-sized powders) are often used, or the filler ratio is significantly reduced (< 40wt%). The former increases costs dramatically and is prone to agglomeration, while the latter sacrifices material rigidity and stone-like texture. Incomplete degassing can easily leave microbubbles (strong scattering sources), and traditional vibration processes have limited effectiveness in eliminating microbubbles in highly filled systems. Production costs are high, and performance improvement faces limitations, especially in achieving the crucial breakthrough of maintaining practical light transmittance (> 30%) and high uniformity (uniformity standard deviation ≤ 5%) at a thickness of > 20 mm.

[0036] (4) Limited application scenarios:

[0037] Its poor light transmission uniformity and thickness limitations make it unsuitable for minimalist designs that require concealed light sources (with the light source flush against the back panel), often necessitating increased light source distance (>100 mm) or the use of a diffusion film, which compromises the aesthetics of the design. Its low hardness and moderate toughness limit its application in high-wear scenarios such as tabletops.

[0038] In summary, existing mineral powder-filled translucent artificial stone has inherent defects such as high scattering due to refractive index mismatch, light path blockage and poor uniformity caused by disordered accumulation of fillers, difficulty in balancing high filling and high performance, complex and costly processes, and weak ability to hide light sources. These defects severely restrict its application in broader and more demanding scenarios. Summary of the Invention

[0039] The present invention aims to overcome the shortcomings of the prior art and provide a whisker-shaped translucent artificial stone that not only has high light transmittance but also excellent light transmission uniformity and mechanical properties, as well as its precision preparation method and specific applications.

[0040] This invention provides a translucent artificial stone with whisker-like inclusions, composed of the following components by weight percentage:

[0041] (1) 55% ~ 75% anhydrous calcium sulfate whiskers; (2) 35% ~ 45% unsaturated resin; (3) 0.2% ~ 1% curing agent.

[0042] The key feature of the translucent artificial stone with whiskers is:

[0043] (a) Specific whisker morphology: The anhydrous calcium sulfate whiskers have a high aspect ratio of 30 to 80, and their surface is modified with axially extending subwavelength cylindrical protrusions, the average width of which is 50 to 200 nanometers. Preferably, the average height of the protrusions is 20 to 100 nanometers, and the protrusions have a complete coverage of ≥ 90% of the whisker surface.

[0044] (b) Precise optical matching: The anhydrous calcium sulfate whiskers have a refractive index of 1.59, and the selected unsaturated resin has a refractive index of 1.57, with a refractive index difference of ≤ 0.02. The whiskers and resin form a gradient refractive index (GRIN) structure at the interface through a specific process, which greatly reduces interfacial light scattering.

[0045] (c) Unique three-dimensional structure and properties: The whiskers are stacked in the resin matrix through micromechanical interlocking to form a continuous and stable three-dimensional network structure. This structure enables the 20 mm thick plate to achieve a light transmittance of 30% to 40% at a wavelength of 550 nm, with excellent light transmittance uniformity and a standard deviation of ≤ 5%.

[0046] This invention provides a method for preparing the above-mentioned translucent artificial stone with whiskers, the method comprising the following steps:

[0047] (1) Stepwise mixing: First, mix the whiskers and resin for 10 minutes under mild conditions of 40 ℃ and 30 rpm to form a pre-wetting layer; then raise the temperature to 60 ℃ and increase the speed to 90 rpm to continue mixing for 15 minutes. This stage aims to deeply trigger the interfacial optical coupling between the resin and the whisker surface.

[0048] (2) Vacuum vibration exhaust: This step is divided into two stages:

[0049] Phase 1: Vibrate continuously for 5 to 15 minutes at a higher vibration frequency of 30 to 50 Hz and an amplitude of 0.2 to 0.4 mm at 25 to 40 ℃, aiming to completely break up agglomerates and promote whisker dispersion and initial orientation.

[0050] Phase Two: At 55-65℃, reduce the vibration frequency to 10-20 Hz and the amplitude to 0.05-0.1 mm, and continue vibration for 5-10 minutes. This low-frequency micro-vibration phase aims to precisely induce interlocking stacking of whiskers through surface protrusions and eliminate microbubbles. The end of the process is determined by observing the disappearance of the specular reflection on the material surface or by using a needle scratch test to detect the absence of leveling.

[0051] (3) Graded curing: Turn off the vibration, heat the material to 80 ~ 90 ℃ and keep it at the temperature for 2 - 3 hours for initial curing; then continue to heat to 120 ℃ and keep it at the temperature for 2 - 4 hours for deep curing to ensure that the three-dimensional network structure is completely stable.

[0052] (4) Cooling and demolding: After the cured board is cooled to 60 ℃, it is demolded to obtain the final product.

[0053] The beneficial effects of this invention include:

[0054] (1) High transmittance and high uniformity: Through the synergistic optical design of “refractive index matching + gradient interface + three-dimensional light channel”, a transmittance of 30% - 40% and a uniformity standard deviation of ≤ 5% were achieved with a high fill thickness of 20 mm, which solved the industry problem of sharp drop in transmittance and serious light spot of traditional thick plate materials.

[0055] (2) Excellent mechanical properties: The three-dimensional network formed by the interlocking of surface protrusions of the whiskers plays a significant role in strengthening and toughening, overcoming the shortcomings of traditional translucent stone surface hardness and brittleness.

[0056] (3) Excellent light source concealment capability: The extremely high light transmission uniformity enables the product to achieve uniform light output when the light source distance is ≤ 50 mm, which meets the needs of high-end minimalist design and broadens the application scenarios.

[0057] (4) The process is controllable and cost-effective: The preparation method has clear parameters, especially the two-stage vacuum vibration degassing process, which effectively ensures the formation of the network structure and the elimination of microbubbles, and the high filling ratio reduces the cost of raw materials. Attached Figure Description

[0058] Figure 1 This is a scanning electron microscope (SEM) image of the surface morphology of the anhydrous calcium sulfate whiskers described in this invention. The image clearly shows the microstructure of the axially extending subwavelength cylindrical protrusions on the whisker surface, specifically reflecting the average width (50-200 nm) and morphology of the protrusions as defined in feature (a) of claim 1, and providing a visual basis for the average height and coverage of the protrusions in dependent claim 2.

[0059] Figure 2 This is a scanning electron microscope (SEM) image of the cross-sectional structure of the translucent artificial stone prepared according to Example 2 of this invention. The image visually demonstrates the three-dimensional network structure formed by the interlocking stacking of anhydrous calcium sulfate whiskers in a resin matrix after processing using the specific process of this invention. The image shows that the whiskers hook and overlap with each other through protrusions on their surfaces, forming a continuous and stable spatial framework. This is key structural evidence for achieving the high transmittance, high uniformity, and excellent mechanical properties described in feature (c) of claim 1.

[0060] Figure 3 These are photos comparing the light transmission effects of artificial stone panels prepared with different fillers. Figure 3 (a) is a light transmission effect diagram of an artificial stone panel prepared according to the method of the present invention using anhydrous calcium sulfate whiskers as filler; Figure 3 (b) is a light transmittance image of an artificial stone panel prepared according to the method of Comparative Example 1 using conventional aluminum hydroxide (ATH) powder as filler. Both images were taken under the same thickness (20 mm) and light source conditions. This comparison clearly shows that the product of this invention ( Figure 3 a) The light is soft and uniform, with no visible light spots or bright / dark stripes; while the comparison product ( Figure 3 (b) Poor light transmittance. This figure provides a visual demonstration of the ultra-high light transmittance uniformity (standard deviation ≤ 5%) achieved by this invention and its excellent effect in light source concealment applications. Specific Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below through multiple embodiments and comparative examples. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions or conditions recommended by the manufacturer.

[0062] Example 1:

[0063] A translucent artificial stone with whiskers is prepared from the following components by weight percentage: 55% anhydrous calcium sulfate whiskers (aspect ratio 50, average width of surface protrusions 100 nm, average height 60 nm, coverage ≥ 92%), 44.8% resin mixture (composed of 80 wt% phthalic unsaturated polyester resin and 20 wt% MMA monomer), and 0.2% methyl ethyl ketone peroxide curing agent.

[0064] Preparation method: Step-by-step mixing (Stage 1: 40 ℃, 30 rpm, 10 min; Stage 2: 60 ℃, 90 rpm, 15 min); Vacuum vibration degassing (Stage 1: 30 ℃, 40 Hz, 0.3 mm amplitude, 10 min; Stage 2: 60 ℃, 15 Hz, 0.08 mm amplitude, 8 min, until the specular reflection disappears); Curing (85 ℃, 2.5 h → 120 ℃, 3 h); Cooling to 60 ℃ for demolding to obtain a 20 mm thick sheet.

[0065] Performance: Light transmittance 40.1%, uniformity standard deviation 4.1%, bending strength 42.2 MPa, light source hiding distance 50 mm.

[0066] Example 2:

[0067] A translucent artificial stone with whiskers, which differs from Example 1 in that: the mass percentage of anhydrous calcium sulfate whiskers is 65%, and the mass percentage of the resin mixture is 34.8%.

[0068] Performance: Light transmittance 35.5%, uniformity standard deviation 4.5%, bending strength 46.7 MPa, light source hiding distance 50 mm.

[0069] Example 3:

[0070] A translucent artificial stone with whiskers, which differs from Example 1 in that: the mass percentage of anhydrous calcium sulfate whiskers is 75%, and the mass percentage of the resin mixture is 24.8%.

[0071] Performance: Light transmittance 30.8%, uniformity standard deviation 4.9%, bending strength 48.5 MPa, light source hiding distance 50 mm.

[0072] Example 4:

[0073] A type of translucent artificial stone with whiskers, which differs from Example 2 in that: the anhydrous calcium sulfate whiskers used have an aspect ratio of 80, and the amount of MMA monomer added accounts for 25% of the total mass of the resin.

[0074] Performance: Light transmittance 36.2%, uniformity standard deviation 4.3%, bending strength 50.3 MPa, light source hiding distance 45 mm.

[0075] Example 5:

[0076] A type of translucent artificial stone with whiskers, which differs from Example 2 in that the parameters of the vacuum vibration exhaust stage 2 are adjusted to 60 ℃, 10 Hz, 0.05 mm amplitude, and 10 min.

[0077] Performance: Light transmittance 35.1%, uniformity standard deviation 4.2%, bending strength 50.1 MPa, light source hiding distance 48 mm.

[0078] Example 6:

[0079] A type of translucent artificial stone with whiskers, which differs from Example 2 in that the amount of MMA monomer added accounts for 15% of the total mass of the resin.

[0080] Performance: Light transmittance 34.9%, uniformity standard deviation 4.7%, bending strength 48.8 MPa, light source hiding distance 55 mm.

[0081] Comparative Example 1:

[0082] A conventional translucent artificial stone is composed of 65% ordinary aluminum hydroxide powder (average particle size 15 μm, refractive index ≈1.57), 34.8% phthalic unsaturated polyester resin (MMA-free), and 0.2% curing agent. It is cured under the same conditions as in Example 1, using a conventional mixing process (60℃, 50 rpm, 30 min) followed by static vacuum degassing (-0.09 MPa, 15 min).

[0083] Performance: Light transmittance 12.3%, uniformity standard deviation 16.8%, bending strength 28.4 MPa, light source hiding distance > 100mm.

[0084] Comparative Example 2:

[0085] A comparative artificial stone, whose composition and preparation process are the same as in Example 2, has the key difference in that the anhydrous calcium sulfate whiskers used are polished, have a smooth surface, and do not have any subwavelength cylindrical protrusions.

[0086] The specific method for whisker polishing is as follows: Anhydrous calcium sulfate whiskers are placed in a 0.5 mol / L hydrofluoric acid (HF) aqueous solution and ultrasonically treated at 25 °C for 30 minutes. Subsequently, they are repeatedly washed with deionized water until neutral and dried at 110 °C for later use. Scanning electron microscopy (SEM) characterization confirmed that the original subwavelength cylindrical protrusion structure on the surface of the treated whiskers had completely disappeared.

[0087] Performance: Light transmittance 28.1%, uniformity standard deviation 9.8%, bending strength 41.5 MPa, light source hiding distance 80 mm.

[0088] Comparative Example 3:

[0089] A comparative artificial stone has the same composition as Example 2, but its preparation process omits the vacuum vibration degassing stage 2, and only performs vibration in stage 1 before curing.

[0090] Performance: Light transmittance 21.5%, uniformity standard deviation 8.5%, flexural strength 41.2 MPa, light source concealment distance 75 mm. Micro-bubbles are visible inside the board.

[0091] Results analysis:

[0092] As demonstrated in Examples 1 to 6, under the component ratios and preparation processes provided by this invention, the resulting whisker-textured translucent artificial stone exhibits excellent comprehensive performance at a thickness of 20 mm: light transmittance ranges from 30.8% to 40.1%, the standard deviation of light transmittance uniformity is no higher than 5%, and the flexural strength is significantly higher than 40 MPa (referencing the flexural strength limit in the standard GBT41919-2022 for artificial stone building slabs). Furthermore, a light source concealment distance of no more than 55 mm can be achieved in all cases. This indicates that this invention can be implemented within a whisker filling range of 55% to 75%, an MMA addition range of 15% to 25%, and within specific process parameter windows, with stable and reliable results.

[0093] Comparative Example 1 used traditional fillers and conventional processes, and all its properties were far inferior to those of the present invention, demonstrating the innovation of the present invention in the selection of material system.

[0094] Although Comparative Example 2 used the same whisker principal component, its optical and mechanical properties could not reach the level of this invention due to the lack of key subwavelength protrusion structures on the whisker surface. This proves that subwavelength cylindrical protrusions on the whisker surface are indispensable for achieving the effects of this invention.

[0095] Comparative Example 3 used the formulation of this invention but simplified the core process, failing to achieve the formation of a three-dimensional stacked whisker structure. Its light transmission uniformity decreased, the light source hiding distance increased, and air bubbles were present inside, demonstrating that the two-stage vacuum vibration degassing process, especially the low-frequency micro-vibration in stage 2, is crucial for forming a defect-free interlocking network structure.

[0096] In summary, this invention, through the organic combination of component design and process control, successfully prepared a whisker-shaped translucent artificial stone that combines high light transmittance, ultra-high light transmittance uniformity, high mechanical strength, and meets the requirements of minimalist light source concealment design. Its comprehensive performance far exceeds that of existing technology products.

Claims

1. A whisker-reinforced translucent artificial stone, composed of 55-75 wt% anhydrous calcium sulfate whiskers, 35-45 wt% unsaturated resin, and 0.2-1 wt% curing agent, characterized in that: (a) The anhydrous calcium sulfate whiskers have an aspect ratio of 30 to 80 and have axially extending subwavelength cylindrical protrusions on their surface, with an average width of 50 to 200 nm. (b) Anhydrous calcium sulfate whiskers have a refractive index of 1.59, and resin has a refractive index of 1.

57. The difference between the two is ≤ 0.02, forming a gradient refractive index interface; (c) The unsaturated resin component is an orthophthalic resin with added MMA monomer, and the amount of added MMA monomer is 10% to 25%; (d) The whiskers interlock and stack in the resin matrix to form a three-dimensional network, so that the transmittance of the 20 mm thick plate reaches 30% ~ 40% at a wavelength of 550 nm, and the standard deviation of transmittance uniformity is ≤ 5%.

2. The translucent artificial stone with whiskers according to claim 1, characterized in that: The average height of the subwavelength cylindrical protrusions is 20 ~ 100 nm, and the protrusions have a complete coverage rate of ≥ 90%.

3. A method for preparing translucent artificial stone with whiskers as described in any one of claims 1-2, comprising the following steps: (a) Stepped mixing: Whiskers and resin were mixed at 30 rpm for 10 minutes at 40 ℃ to form a pre-wetted layer; Heat to 60 °C and mix at 90 rpm for 15 minutes to trigger interfacial optical coupling; (b) Vacuum vibration exhaust: Phase 1: Vibrate continuously for 5 to 15 minutes at a vibration frequency of 30 to 50 Hz and an amplitude of 0.2 to 0.4 mm at 25 to 40 ℃; Phase 2: Vibrate at 55 ~ 65 ℃ with a vibration frequency of 10 ~ 20 Hz and an amplitude of 0.05 ~ 0.1 mm for 5 ~ 10 minutes until the mirror reflection on the material surface disappears or there is no leveling in the needle scratch test; (c) Curing: Turn off vibration and heat to 80-90℃ to cure for 2-3 hours; Continue heating to 120℃ and cure for 2 to 4 hours; (d) Demold after cooling to 60 ℃.

4. The application of the whisker-shaped translucent artificial stone as described in any one of claims 1-2 in translucent architectural decorative materials, such as as wall panels, countertops, partitions, or translucent decorative panels, characterized in that: The thickness of the artificial stone panel is 320 mm; when the panel is used for a light-transmitting structure with a built-in light source, the minimum distance between its back surface and the light source (the light source hiding distance) is ≤ 50 mm, and the standard deviation of the light transmission uniformity of the front surface of the panel is ≤ 5%, so as to achieve a uniform light transmission effect in the state of hiding the light source.

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