Double-foaming floor and mold thereof

Abstract

The invention relates to a double-foamed floor and a mold thereof, and belongs to the technical field of wood-plastic foamed floors. A double-foaming floor comprises a base plate and a weather-proof surface layer, and the base plate comprises a first foaming body composed of first resin and a skinning foaming body composed of second resin; the skinning foaming body comprises a second foaming body and a skinning layer, the skinning layer wraps the second foaming body, and the second foaming body wraps the first foaming body; the first foam has a lower density than the second foam. Through a dual-foaming mechanism, a high-foaming area-low-foaming area-crust layer organization structure is formed, a low-density center provides light weight and buffering, a high-density periphery achieves structure supporting and load dispersing, the crust surface layer and the weather-resistant surface layer endow wear-resistant and impact-resistant protection, and the final product is not prone to deformation while keeping light. The composite material has excellent compression resistance, bending resistance, impact resistance and weather-resistant surface characteristics, and realizes balanced improvement of mechanical properties and use durability.

Description

Technical Field

[0001] This invention relates to a foamed floor, and more particularly to a double-foamed floor and its mold, belonging to the technical field of wood-plastic foamed floor. Background Technology

[0002] Wood-plastic composites are environmentally friendly materials made by blending wood fibers with thermoplastic plastics. They combine the texture of wood with the corrosion resistance and moisture resistance of plastics, and are widely used in flooring, decorative wall panels, and other fields. However, wood-plastic foam flooring, by introducing a foaming process to reduce material density, while reducing weight and improving thermal and sound insulation performance, also suffers from a significant decrease in mechanical strength due to the introduction of the foam structure, making it difficult to meet the load-bearing and durability requirements of residential and commercial spaces.

[0003] To address the insufficient strength of foamed flooring, existing technologies have proposed a solution involving composite layered reinforcements on both sides of the foamed core layer. For example, invention patent CN 113043704B discloses a typical technique: using resin-impregnated glass fiber mesh as the reinforcing material, two layers of mesh are pre-placed between the foamed core layer and the plastic shell through a mold channel during the board manufacturing process, before co-extrusion, forming a composite structure of mesh, foamed core layer, and plastic shell; subsequently, out-of-mold foaming is performed in the shaping mold. This solution aims to disperse surface stress and improve overall bending resistance through the supporting effect of the resin-impregnated glass fiber mesh.

[0004] However, in the aforementioned flooring, the materials on both sides of the resin-impregnated fiberglass tape have significantly different coefficients of thermal expansion (the plastic-based foam core and the plastic shell have different thermal deformation characteristics). During temperature changes or long-term use, the interface is prone to peel stress, leading to delamination between the mesh and the plastic shell, affecting the structural integrity and lifespan of the flooring. Therefore, a comprehensive optimization of the product and its mold structural design is necessary. Summary of the Invention

[0005] To solve the above-mentioned problems, the present invention provides, in a first aspect, an enhanced foamed flooring.

[0006] A dual-foam flooring includes a substrate and a weather-resistant surface layer covering at least the upper surface of the substrate. The substrate includes a first foam body made of a first resin and a skin foam body made of a second resin. The skin foam body includes a second foam body and a skin layer integrally connected to the second foam body. The second foam body covers the first foam body, and the skin layer covers the second foam body. The first foam body has a lower density than the second foam body.

[0007] In the above-mentioned technical solution of the present invention, a dual foaming mechanism is used to form a high-foaming zone-low-foaming zone-skin layer structure, optimizing the configuration of the foam body and thus improving the strength of the foamed flooring. The specific strengthening mechanism is as follows:

[0008] 1) The first foam (central foam) is a low-density region, and the second foam (peripheral foam) is a relatively high-density region. Through differentiated formulations and / or foaming processes (such as pre-foaming sequence control and parameter control), the first foam achieves a higher foaming ratio, while the second foam reduces the foaming ratio. The first foam has higher porosity and lighter weight, and its density and degree of foaming can be flexibly adjusted. While reducing the overall material density and raw material consumption, it provides filling and a certain degree of support. The second foam surrounds and encapsulates the first foam, has a higher density, and forms a continuous density gradient, playing a role in structural support and transition. It can effectively disperse external loads, avoid stress concentration, and prevent premature deformation or damage. The two foams are supplied through different channels, are independent, and can be freely configured with various parameters.

[0009] 2) The skin foam is located on the outermost side. The skin layer (usually a non-foamed or micro-foamed dense surface layer) has good hardness and wear resistance. Alternatively, it can be co-extruded and coated with a thermoplastic shell, which can significantly improve the floor's scratch resistance, impact resistance and surface durability. The skin layer and the second foam below it (the outer peripheral foam) are integrally foamed and molded, together forming a high-strength "shell" with a continuous density gradient. This not only protects the internal structure but also enhances the overall dimensional stability and bending strength.

[0010] 3) By combining a "low-density center (first foam) + higher-density periphery (second foam) + high-strength skin," a density gradient structure from the outside to the inside is formed. The first foam constructs the low-density area and initially stabilizes the foam structure, while the second foam forms a matching higher-density periphery structure. Through differentiated formulations and / or foaming processes (such as pre-foaming timing control and parameter control), the two adapt to their respective functions. The first foam focuses on lightweighting and support, while the second foam focuses on transition and protection. The skin layer provides the necessary strength and protection, enabling the overall floor to maintain its lightweight while possessing excellent mechanical properties. Because the skin foam has a continuous density gradient, it has a significant and uniform weakening effect from the outside to the inside when transferring and distributing loads. It can evenly distribute the load without transferring all or most of the load to the low-density center (first foam), making the load distribution in the floor adapt to the floor structure and avoiding the obvious "barrel effect."

[0011] This dual foaming mechanism, which independently controls the foaming of the first and second foaming bodies (adjusting the relatively low foaming ratio), or combined with their respective formulation optimizations, creates a density gradient difference. Combined with functional layered design, the material can leverage its advantages in different areas, achieving excellent strength, rigidity, and durability while being lightweight. In particular, it demonstrates balanced performance in key indicators such as compression resistance, bending resistance, and impact resistance, thus optimizing and improving overall performance.

[0012] As a preferred embodiment of the above technical solution, both the first resin and the second resin are PVC.

[0013] As a preferred embodiment of the above technical solution, the density of the first foam body is 0.6~0.8 g / cm³. 3 The density of the second foam is 1.0~1.5 g / cm³. 3 .

[0014] As a preferred embodiment of the above technical solution, the density of the second foam body is at least 40% higher than that of the first foam body.

[0015] As a preferred embodiment of the above technical solution, a layered reinforcement is provided between the first foam and the second foam. More preferably, two layered reinforcements are provided, horizontally disposed on the upper and lower surfaces of the first foam.

[0016] In the above technical solution of the present invention, by providing a layered reinforcing body between the first foam body and the second foam body, in addition to its own reinforcing effect, it also has the following three advantages:

[0017] 1) Excellent interfacial bonding: The layered reinforcement is firmly bonded to the foam on both sides, effectively avoiding the problem of cracking at the interface; and the two foams are not much different in material (such as using the same resin system), which can effectively reduce the interfacial cracking caused by the difference in materials on both sides (synchronous expansion and contraction temperature, synchronous thermal shrinkage rate).

[0018] 2) Effective gradient buffer: There are differences in physical properties (such as compressive strength, elastic modulus, thermal shrinkage rate, etc.) between the first foam and the second foam based on the difference in foaming degree; the layered reinforcement forms a buffer layer between the two, which alleviates the internal stress caused by the difference in foaming degree.

[0019] 3) Significant stress dispersion effect: Under the composite structure of "low density center + high density periphery + high strength skin" of the present invention, when the floor is under pressure (such as when the joists are laid), stress concentration is easily generated in the middle of the interface between the two foams; the layered reinforcement can bear the concentrated stress and effectively disperse it, thereby further improving the compressive strength and load-bearing stability of the floor.

[0020] As a preferred embodiment of the above technical solution, the surface of the first foam body not covered by the layered reinforcement abuts against the second foam body.

[0021] As a preferred embodiment of the above technical solution, it further includes a co-extruded coating shell disposed on the outer periphery of the skin layer.

[0022] As a preferred embodiment of the above technical solution, the second foam body extends downward at at least two sides at the bottom to form a platform that allows the main body to be suspended during flooring installation.

[0023] As a preferred embodiment of the above technical solution, the second foam body extends downward at the center of the bottom to form a second platform that allows the main body to be suspended during flooring installation.

[0024] A second objective of the present invention is to provide a mold for preparing the aforementioned flooring.

[0025] A mold for producing the above-mentioned double-foamed flooring is formed by sequentially connecting multiple mold plates. The mold has a first main channel, a reinforcement channel, a second main channel, a co-extrusion coating channel, and a weather-resistant surface coating channel inside.

[0026] The second main channel includes a jacketed channel whose diameter gradually decreases along the material flow direction;

[0027] The first main channel is internally connected to the jacketed channel;

[0028] The reinforcement channel is internally connected to the jacketed channel;

[0029] The outlet of the reinforcement channel is located between the outlet of the first main channel and the outlet of the second main channel;

[0030] It also includes a foaming cavity that extends to the outlet of the mold;

[0031] The first main channel, the reinforcement channel, and the second main channel are independent of each other and converge to form a unified outlet; the unified outlet is connected to the foaming cavity.

[0032] The outlet of the co-extrusion coating channel is connected to the outlet of the foaming cavity;

[0033] The outlet of the weather-resistant surface coating channel is connected to the outlet of the foaming cavity.

[0034] As a preferred embodiment of the above technical solution, the jacketed channel is formed by joining two adjacent mold plates, each having a recessed top surface and a recessed bottom surface.

[0035] As a preferred embodiment of the above technical solution, the reinforcing channel is formed by joining two adjacent mold plates, each having a top concave surface and a bottom concave surface respectively.

[0036] This mold employs multi-channel zone control and dynamic structural design, forming an integrated flow channel system through the docking of multiple mold plates. This precisely corresponds to the "low-density central foam + higher-density peripheral foam + free skin surface" structure of the double-foamed flooring. Its core design concept is:

[0037] 1) Low-density central foam material is transported through an independent first main channel; the physical interference between the two main channels is solved by utilizing the jacketed constriction channel of the second main channel, and the feeding method of the second main channel is optimized when transporting the second resin, thereby controlling the foaming ratio of the peripheral foam. This constriction structure increases flow resistance through physical flow restriction, so that the peripheral foam material is pre-compressed in the second main channel. After entering the foaming cavity, the degree of foaming is lower than that of the central foam, forming a higher density peripheral structure; the reinforcement channel introduces reinforcement into the stress concentration area (at the interface between the two foams) (optional).

[0038] 2) The reinforcement channel outlet is located between the first and second main channel outlets to ensure that the reinforcement material preferentially enters the central area and fuses with the central foam material (if necessary); each channel / channel (first main channel, reinforcement channel, second main channel) is independent of each other. The conveyed material fuses and foams in the foaming cavity according to the preset method. The central foam forms a high-foaming, low-density area, while the peripheral foam forms a higher-density area surrounding the center due to the flow restriction of the jacketed channel (or the difference in control parameters). The two freely construct a density gradient difference; subsequently, the peripheral foam naturally generates a high-strength skin surface layer through free skin foaming (the material is rapidly cooled and solidified under high temperature and high pressure to form a non-foaming or micro-foaming dense surface layer), without the need for additional co-extrusion channels, ultimately forming a functional layered structure of "low-density center (lightweight filling) + higher-density periphery (structural support) + dense skin (protection)".

[0039] Compared to traditional molds, the mold of this invention directly controls the density of the outer foam (or further controls parameter differences) through the jacketed narrowing physical flow restriction of the second main channel. Combined with the skinning characteristics of the outer foam itself, it forms a substrate surface with a continuous density gradient, which can freely construct density gradient differences. At the same time, the reinforcing channels ensure that the product structure interface is clear, the gradient is stable, and the bonding is solid, accurately achieving the synergistic optimization of lightweight and high strength.

[0040] As a preferred embodiment of the above technical solution, the first main channel has a pre-foaming chamber.

[0041] The technical advantages of setting the pre-foaming chamber in the above-mentioned solution of the present invention are mainly reflected in the following two aspects:

[0042] 1) The pre-foaming chamber provides an independent pre-foaming space for the raw materials transported by the first main channel, so that the central foaming material is foamed and forms a stable low-density structure before entering the main foaming chamber; when the subsequent peripheral foaming material (foamed by flow restriction through a jacketed channel) wraps around it, the difference in the degree of foaming between the two has been initially fixed, thereby directly forming a clear density gradient interface, avoiding the loss of density gradient control caused by synchronous foaming, and ensuring the layered optimization of the mechanical properties of the floor;

[0043] 2) By adjusting the independent space and process parameters (such as temperature, pressure, and residence time) of the pre-foaming chamber, the foaming ratio and porosity of the central foam can be precisely controlled, forming a lightweight structure with high porosity.

[0044] As a preferred embodiment of the above technical solution, the first main channel is used to transport the first resin; the second main channel includes a second resin inlet and two second resin conveying channels that are symmetrically distributed vertically or horizontally, and the outlets of the two second resin conveying channels are connected to the jacketed channel.

[0045] The technical advantages of this preferred design are as follows: After centralized feeding through the second resin inlet, the second resin is evenly distributed into the jacketed channel using symmetrically distributed dual channels. This not only ensures the flow balance and pressure stability of the outer foam material delivery, but also optimizes the internal flow channel layout of the mold through the symmetrical structure, so that the second resin is evenly pressurized and flow-limited in the jacketed channel, thereby ensuring the uniform density distribution and good structural consistency of the outer foam (high density area). At the same time, the dual-channel symmetrical design simplifies the mold processing and assembly precision requirements, improves the mold manufacturing feasibility and long-term operational reliability, and ultimately ensures the accurate construction and stable performance of the gradient structure between the outer high-density area and the central low-density area in the double-foamed floor.

[0046] In summary, the present invention has the following beneficial effects:

[0047] 1. Precisely construct density gradient and functional layering structure: By independently controlling the foaming process of the first foam body (low-density central area) and the second foam body (high-density peripheral area), and combining the pre-foaming cavity of the first main channel and the jacketed narrowing channel of the second main channel, the density gradient difference of "low-density center - high-density periphery" is precisely realized, forming a functional layering of lightweight center and high load-bearing periphery, which significantly improves the comprehensive mechanical performance of the floor.

[0048] 2. Strong process self-controllability: The first foaming body can be preferentially foamed and shaped through the pre-foaming chamber, and the second foaming body can reduce the foaming ratio through physical flow restriction of the jacketed channel. Both can flexibly adjust the density and porosity through independent formulations (such as resin type and foaming agent ratio) or process parameters (such as temperature and pressure). At the same time, it supports the introduction of reinforcing materials through the reinforcing body channel (layered reinforcing bodies, such as resin-impregnated reinforcing fiber mesh, can be directly input; melt resin used to form the reinforcing body, such as ABS, can also be directly input), adapting to the differentiated needs of different scenarios for cushioning and support.

[0049] 3. Stable structure and reliable interface bonding: The central foam and the peripheral foam are transported through independent flow channels and fused sequentially in the foaming cavity, with a clear density gradient interface; the peripheral foam naturally forms a high-strength and dense surface layer (skin layer) at the mold exit through free skin foaming, without the need for additional co-extrusion flow channels, avoiding structural homogenization caused by the mixing of multiple layers of materials, and ensuring that each functional layer is firmly bonded and performs synergistically.

[0050] 4. The mold design is efficient and reliable: The second main channel adopts a symmetrically distributed double material conveying channel connected by a jacketed constriction structure to ensure uniform and stable material conveying on the outer periphery; the pre-foaming chamber and the independent layout of the multi-channel reduce mutual interference of materials, improve the consistency and repeatability of product structure during the production process, and are suitable for large-scale stable production.

[0051] 5. Significantly optimized overall performance: The low-density center provides lightweighting and cushioning, the high-density periphery provides structural support and load distribution, and the skin and weather-resistant surface (co-extruded coating optional) provide wear-resistant and impact-resistant protection. The final product maintains its lightweight properties while also possessing excellent compressive strength, bending strength, impact resistance, and weather-resistant surface characteristics, achieving a balanced improvement in mechanical properties and service durability. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the floor structure in Example 1;

[0053] Figure 2 yes Figure 1 A magnified view of a portion of the image;

[0054] Figure 3 This is a schematic diagram of the overall mold structure of Example 1;

[0055] Figure 4 This is a schematic diagram of the floor structure in Example 2;

[0056] Figure 5 This is a front view of the third mold plate in Embodiment 2 of the present invention;

[0057] In the diagram, the component names represented by each number are as follows:

[0058] 1-Substrate,

[0059] 2-Weather-resistant surface layer,

[0060] 11-First foam body,

[0061] 12-Layered Reinforcement

[0062] 13-Cerebrolysin,

[0063] 13' - platform,

[0064] 13'' - Second pad,

[0065] 131-Second foam body,

[0066] 132-Cereary layer,

[0067] 14- Co-extruded surface layer,

[0068] 2-Weather-resistant surface layer,

[0069] A - First mold plate,

[0070] B - Second mold plate,

[0071] C - Third mold plate,

[0072] D - Fourth mold plate,

[0073] E-Fifth mold plate,

[0074] F-Sixth mold plate,

[0075] G-Fifth mold plate,

[0076] H-Seventh mold plate,

[0077] S1 - The first main road,

[0078] S2-Reinforcement Channel

[0079] S3 - Second Main Road

[0080] S4 - Foaming chamber

[0081] S5 - Co-extrusion coated flow channel

[0082] S6 - Weather-resistant surface coating flow channel,

[0083] S7 - At the discharge port

[0084] S1-1 - Pre-foaming chamber,

[0085] S3-1 - Second resin inlet,

[0086] S3-2 - Second resin conveying channel

[0087] S3-3-Jacketed Channel. Detailed Implementation

[0088] The present invention will be further explained and described below with reference to the accompanying drawings.

[0089] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. Any changes made by those skilled in the art after reading this specification, as long as they fall within the scope of the claims, will be protected by patent law.

[0090] Example 1

[0091] This embodiment provides a double-foamed flooring based on polyvinyl chloride (PVC) resin, such as... Figures 1-2 As shown, its structure includes: a substrate 1 and a weather-resistant surface layer 2. The substrate 1 includes a foam and a co-extruded coating surface layer 14. The foam includes a first foam 11 and a skin foam 13. Specifically, the substrate structure from the inside out is as follows: a low-density first foam 11, a layered reinforcement 12, a higher-density second foam 131, a skin layer 132, and a co-extruded coating surface layer 14. Among them, the second foam 131 and the skin layer 132 are integrally connected to form the skin foam 13.

[0092] First foam 11: The central foam, made of polyvinyl chloride as the base resin (first resin), with a density controlled at approximately 0.6 g / cm³, serves as a lightweight filling structure for the flooring. During production, raw materials are transported through an independent main channel and pre-foamed to form a low-density zone with high porosity.

[0093] Layered reinforcement 12: In this embodiment, it is a glass fiber mesh impregnated with ABS resin, with a thickness of about 1.0 mm.

[0094] Second foam 131: Based on polyvinyl chloride (PVC) resin (second resin), with an average density controlled at approximately 1.25 g / cm³ (based on the average density due to a continuous density gradient), it encapsulates the central foam and provides the main structural support. During production, the raw material is transported through an independent main channel, which is a jacketed structure with a gradually decreasing diameter along the material flow direction (formed by the contact of the concave top and bottom surfaces of adjacent mold plates). This physically restricts the flow of the outer foam material (containing the second resin) during transport, reducing the foaming ratio.

[0095] Skin layer 132: Also called free skin surface layer, it is naturally formed by the outer foam through free skin foaming. That is, the material is rapidly cooled and solidified on the surface under high temperature and high pressure (rapid cooling under pressure, such as jacket water cooling), forming a non-foamed or micro-foamed dense surface layer (density of about 1.6 g / cm³, thickness of about 200 μm), covering the outermost side of the floor, providing physical protection such as scratch resistance, impact resistance and wear resistance.

[0096] The aforementioned low-density central foam material, layered reinforcement, and peripheral foam material conveyed by the second resin conveying channel are transported separately through independent channels and fused and initially foamed in the foaming cavity in the order of "low-density center + layered reinforcement + high-density periphery," forming a density gradient structure from the inside to the outside. After leaving the foaming cavity, the peripheral foam naturally forms a skin surface layer through free skin foaming, without the need for additional co-extrusion channels, ultimately forming a three-layer functional structure of "low-density center (lightweight filling) + intercalation reinforcement + higher-density periphery (structural support) + dense skin (protection)" (the second foam 131 and the skin layer 132 are integrated).

[0097] The co-extruded coating layer 14 and the weather-resistant coating layer 2 are existing technologies, so they will not be described in detail here.

[0098] The mold used in this embodiment is a multi-channel integrated mold, such as... Figure 3 As shown, this specifically includes the first to seventh mold plates (A to G), each with a structure corresponding to various flow channels or passages. The components work together to achieve integrated extrusion molding of a "low-density center (lightweight filling) + intercalation reinforcement + high-density periphery (structural support) + dense skin (protection)". For example... Figure 3 As shown, the mold composition and runner design are as follows:

[0099] First main channel S1: Used for independently conveying the first resin (low-density central foam raw material), which includes a pre-foaming chamber S1-1. The pre-foaming chamber is an independent space located at the rear of the first main channel, so that the first resin is foamed to a certain extent before entering the main foaming chamber and achieves a preliminary stable low-density structure, and accurately controls the foaming ratio and porosity of the central foam.

[0100] The second main channel S3 includes a second resin inlet S3-1, two second resin conveying channels S3-3 symmetrically distributed vertically, and a jacketed channel S3-3; the outlets of the two second resin conveying channels are connected to the jacketed channel S3-3; the jacketed channel is formed by the concave top and concave bottom surfaces of adjacent mold plates (D, E), and the channel diameter gradually decreases along the material flow direction, thereby reducing the foaming ratio of the outer foam body through physical flow restriction, making its density higher than that of the central foam body.

[0101] Reinforcing channel S2: It is formed by the top and bottom recessed surfaces of adjacent mold plates (F, G) coming together. The outlet is located between the first main channel outlet and the second main channel outlet. It is used to introduce layered reinforcement (or raw materials for forming layered reinforcement to form a reinforced structure in the later stage) between the two foams to further improve the mechanical properties of the central region.

[0102] Foaming cavity S4: also known as the main foaming cavity. The first main flow channel S1, the reinforcement channel S2, and the second main flow channel S3 are independent of each other and converge to form a unified outlet; the unified outlet is connected to the foaming cavity S4; that is, the materials transported by the above three independent flow channels / channels are integrated here and gradually foamed and formed, while being transported forward; among them, the central foam body forms a low-density area due to pre-foaming and shaping, and the outer peripheral foam body forms a high-density area due to the flow restriction of the jacketed channel, and the two naturally create a density gradient difference; the layered reinforcement between the two to a certain extent physically isolates the two foaming areas and stabilizes their respective foaming densities (in the area covered by the layered reinforcement, the two foaming areas form a clear separation; in the area not covered by the layered reinforcement, the two foaming areas form a transitional connection, and the separation may not be obvious, especially in the thickness direction). The S4 foaming chamber also has a skin formation zone: the outer foam body naturally generates a dense surface layer (skin layer) through free skin foaming in the foaming chamber, without the need for co-extrusion channels, ensuring a strong bond between the surface layer and the outer foam body interface, giving the floor surface high wear resistance and impact resistance.

[0103] The mold also includes a co-extrusion coating channel S5 and a weather-resistant surface coating channel S6, both of which converge at the outlet S7 of the foaming cavity S4. Both the co-extrusion coating channel S5 and the weather-resistant surface coating channel S6 are existing technologies and will not be described in detail here.

[0104] The production process in this embodiment is as follows:

[0105] Step 1: Raw material preparation: Mix polyvinyl chloride resin with foaming agent, etc. (the first resin is used for the central foam and the second resin is used for the peripheral foam. The proportion of foaming agent is adjusted according to the density requirements). After being heated and melted by two extruders, the central foam melt and the peripheral foam melt are formed.

[0106] Step 2: Mold closing and runner preheating: Assemble and lock the mold plates together, and turn on the power to heat the main runner, the second main runner and the foaming cavity to the set temperature.

[0107] Step 3: Co-extrusion molding: The raw material melt of the central foam body is conveyed through the first main channel S1 and pre-foamed in the pre-foaming chamber; the resin-impregnated glass fiber mesh is conveyed through the reinforcement channel S2; the raw material melt of the peripheral foam body is conveyed through the second main channel S3; the pre-foamed pre-formed structure of the central foam body melt, the resin-impregnated glass fiber mesh, and the peripheral foam body melt are sequentially fused and gradually foamed in the foaming chamber; the peripheral foam body wraps the central foam body through the resin-impregnated glass fiber mesh and forms a density gradient structure; after the material leaves the foaming chamber, the surface of the peripheral foam body forms a dense skin surface layer through free skin foaming; then, the thermoplastic shell (PVC) and weather-resistant ASA are co-extruded and coated, and finally uniformly extruded through the die discharge plate, and after cooling and shaping, a double-foamed floor is obtained.

[0108] Example 2

[0109] Given that traditional flooring has a flat structure on both the upper and lower surfaces, and the lower surface is in complete contact with the ground or joists during installation, it has defects such as being unable to be fully laid flat if the dimensions are slightly irregular, being greatly affected by moisture, having insufficient ventilation, and being limited in size changes due to thermal expansion and contraction. This embodiment designs an asymmetrical irregular-shaped floor with a "small bridge pier" structure.

[0110] It is largely the same as Example 1, except that: Figure 4 As shown, the second foam 131 extends downward at the two sides and the center of the bottom to form a platform 13' (two sides) and a second platform 13'' (center) that allow the main body to be suspended during flooring installation.

[0111] However, during extrusion, the complex surface structure of this structure, coupled with the significant difference in resistance between the upper and lower surfaces, leads to an imbalance between the melt flow rate and the internal pressure, which brings difficulties to the extrusion process (mainly the extrusion difficulties of the co-extruded coating layer and the weather-resistant coating layer).

[0112] Therefore, we made appropriate adjustments to the mold structure based on Example 1 (the overall structural schematic remains unchanged). Specifically, as follows... Figure 5 As shown. Figure 5 This is the front view of the third mold plate, from... Figure 5 It can be seen that: 1. The upper and lower material conveying channels of the co-extrusion coating channel S5 are both divided into two branches, thereby improving the uniformity of resin melt distribution in the "U-shaped channel" of the thermoplastic shell and the uniformity of material distribution to the foaming cavity S4; 2. The bottom contour of the foaming cavity corresponds to the pad 13' and the second pad 13''. At the same time, the weather-resistant surface coating channel S6 is also designed in the same way, and the figure is omitted.

Claims

1. A double-foamed floor panel, comprising a substrate (1) and a weather-resistant surface layer (2) covering at least the upper surface of the substrate, the substrate (1) comprising a first foamed body (11) made of a first resin and a skin-foamed body (13) made of a second resin; the skin-foamed body comprising a second foamed body (131) and a skin layer (132) integrally connected with the second foamed body, the second foamed body (131) covering the first foamed body (11), and the skin layer (132) covering the second foamed body (131); the first foamed body (11) having a lower density than the second foamed body (131).

2. The double-foamed floor panel according to claim 1, characterized in that: The first resin and the second resin are both PVC.

3. The double-foamed floor panel according to claim 1, wherein: The first foam (11) has a density of 0.6 to 0.8 g / cm 3 ; and the second foam (131) has a density of 1.0 to 1.5 g / cm 3 .

4. The dual-foamed floor panel of claim 3, wherein: The density of the second foamed body (131) is at least 40% higher than that of the first foamed body (11).

5. The dual-foamed floor panel of claim 1, wherein: A layered reinforcement (12) is arranged between the first foamed body (11) and the second foamed body (131).

6. The dual-foamed floor panel of claim 5, wherein: The surface of the first foamed body (11) not covered by the layered reinforcement (12) is in abutment with the second foamed body (131).

7. The dual-foamed floor panel of claim 1, wherein: A co-extrusion shell is further arranged at the periphery of the skin layer (132).

8. The dual-foamed floor panel of claim 1, wherein: The second foamed body (131) extends downward at at least two side ends of the bottom to form a pad (13') that can elevate the main body of the floor panel when laid.

9. The dual-foamed floor panel of claim 8, wherein: The second foamed body (131) extends downward at a central position of the bottom to form a second pad (13'') that can elevate the main body of the floor panel when laid.

10. A mold for producing the double-foamed floor panel according to any one of claims 1 to 9, which is formed by sequentially butting a plurality of mold plates, characterized in that: Internally, a first main flow channel (S1), a reinforcement channel (S2), a second main flow channel (S3), a co-extrusion flow channel (S4), and a weather-resistant surface layer covering channel (S6) are arranged; The second main flow channel (S3) comprises a jacketed channel (S3-3) with a gradually decreasing diameter along the direction of material flow; The first main flow channel (S1) is in communication with the jacketed channel (S3-3) internally; The reinforcement channel (S2) is in communication with the jacketed channel (S3-3) internally; The outlet of the reinforcement channel (S2) is arranged between the outlets of the first main flow channel (S1) and the second main flow channel (S3); A foaming cavity (S4) is further arranged, with the cavity extending to the discharge opening (S7) of the mold; The first main flow channel (S1), the reinforcement channel (S2), and the second main flow channel (S3) are independent of each other and converge to form a unified outlet; the unified outlet is connected to the foaming cavity (S4); The outlet of the co-extrusion flow channel (S5) is connected to the discharge opening (S7) of the foaming cavity (S4); The outlet of the weather-resistant surface layer covering channel (S6) is connected to the discharge opening (S7) of the foaming cavity (S4).

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