Anti-cracking heat-insulating extruded polystyrene board and preparation method thereof

Abstract

The invention relates to the technical field of extruded polystyrene boards, in particular to an anti-cracking heat-preservation extruded polystyrene board which comprises an extruded polystyrene board body bonded to a granary storage wall, the extruded polystyrene board body comprises an extruded board base board layer, graphite particles pretreated by a silane coupling agent are evenly dispersed in the extruded board base board layer, and the graphite particles are evenly dispersed in the extruded board base board layer. A first anti-overflow glue layer, a first alkali-resistant glass fiber mesh layer and a first ultraviolet curing coating are sequentially compounded at the top of the extruded sheet substrate layer from inside to outside. Benefited from an efficient heat insulation network constructed by the pretreated graphite and the nano nucleating agent, the heat conductivity coefficient of the plate is remarkably reduced to 0.019-0.022 W / (m.K), the heat insulation efficiency is improved by about 30% compared with that of a traditional product, the refrigeration energy consumption of a granary is effectively reduced, and the 28-day size change rate of the product is stabilized at an extremely low level of 0.05-0.09% and is less than 1 / 5 of that of the traditional product through multiple stabilization design, so that the energy consumption of the granary is effectively reduced. And the problems of slab joint cracking and cold bridge caused by shrinkage are fundamentally avoided.

Description

Technical Field

[0001] This invention relates to the field of extruded polystyrene board technology, specifically to a crack-resistant and heat-insulating extruded polystyrene board and its preparation method. Background Technology

[0002] During grain storage, insulation materials are needed to maintain a stable temperature and humidity environment inside the warehouse to prevent grain from becoming moldy, infested by insects, and condensing. Extruded polystyrene (XPS) boards are commonly used as grain warehouse insulation materials due to their low thermal conductivity and good insulation performance.

[0003] Currently, commercially available traditional extruded polystyrene boards have the following main drawbacks in grain silo applications: 1. Poor dimensional stability: Due to insufficient aging time during production, the boards are prone to shrinkage and creep under changes in ambient temperature and long-term static load of grain piles, resulting in widening of board gaps and the formation of cold bridges.

[0004] 2. Weak interfacial adhesion: Its surface is smooth and chemically inert, resulting in poor adhesion to inorganic mortar substrates. It is prone to hollowing during construction, and thermal stress can easily lead to interfacial debonding during long-term use.

[0005] 3. Insufficient weather resistance and mechanical properties: Under the significant temperature fluctuations in grain silos, the boards are prone to warping and bulging; at the same time, they are brittle and have poor impact resistance, making them easy to break during loading and unloading operations.

[0006] 4. Environmental hazards: Some products add harmful substances such as HBCD to meet flame retardant requirements, posing environmental and health risks.

[0007] In summary, we propose a crack-resistant and heat-insulating extruded polystyrene board and its preparation method. Summary of the Invention

[0008] The purpose of this invention is to provide a crack-resistant and heat-insulating extruded polystyrene board and its preparation method, which has the advantages of safety, stability and high efficiency, and solves a series of coupled problems of existing extruded polystyrene boards such as shrinkage deformation, interfacial adhesion, heat stress resistance and long-term durability.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a crack-resistant and heat-insulating extruded polystyrene board, comprising: An extruded polystyrene board is bonded to the wall of a grain storage silo. The extruded polystyrene board includes an extruded board substrate layer. The extruded board substrate layer contains graphite particles that have been pretreated with a silane coupling agent. The top of the extruded board substrate layer is sequentially laminated with a first anti-overflow adhesive layer, a first alkali-resistant fiberglass mesh layer, and a first UV-curable coating layer from the inside out. The bottom of the extruded board substrate layer is sequentially laminated with a second anti-overflow adhesive layer, a second alkali-resistant fiberglass mesh layer, and a second UV-curable coating layer from the inside out.

[0010] Preferably, the raw materials of the extruded board substrate layer, by weight percentage, include: The composition includes 88-93% polystyrene resin, 2-5% pretreated graphite particles, 3-5% environmentally friendly foaming agent, 0.5-1.5% nucleating agent, 0.3-0.8% composite antioxidant, and 0.2-0.7% ultraviolet absorber. The composite antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] as the primary antioxidant and tris(2,4-di-tert-butylphenyl) phosphite as the secondary antioxidant in a mass ratio of 2:1 to 3:1.

[0011] Preferably, the environmentally friendly foaming agent is HFO-1336mzz, and the nucleating agent is nano-sized talc powder with a particle size D50 of 1-5μm.

[0012] Preferably, the raw materials of the first and second anti-spill adhesive layers, by weight percentage, include: Waterborne epoxy resin 55-65%, polyurethane toughening agent 15-25%, latent amine curing agent 12-18%, reactive diluent 3-7%; The coating thickness of the first and second anti-overflow adhesive layers is 0.3-0.5 mm.

[0013] Preferably, the first and second alkali-resistant fiberglass mesh layers have a basis weight of 160-200 g / m², a mesh size of 4 mm × 4 mm or 5 mm × 5 mm, and their surfaces are coated with a sizing agent containing a silane coupling agent. Their alkali resistance retention rate is ≥92%, and their tensile strength is ≥1500 N / 50 mm.

[0014] Preferably, the raw materials for the first and second UV-curable coatings, by weight percentage, include: The composition includes: 80-90% aliphatic polyurethane acrylate resin, 3-8% photoinitiator 1-hydroxycyclohexylphenyl ketone, 2-5% silane coupling agent KH-560, 0.5-2% leveling agent, and 0.5-1.5% defoamer. The dry film thickness of the first UV-curable coating and the second UV-curable coating is 0.1-0.2 mm.

[0015] A method for preparing the crack-resistant and heat-insulating extruded polystyrene board includes the following steps: S1. Raw material pretreatment: Place graphite particles in an ethanol solution of silane coupling agent KH-550 with a concentration of 1-2wt%, disperse ultrasonically for 20-40 minutes, filter, and dry at 80-100℃ to obtain pretreated graphite particles. S2. Preparation of extruded polystyrene board substrate: Polystyrene resin, pretreated graphite particles, foaming agent, nucleating agent, composite antioxidant and ultraviolet absorber are mixed according to the formula, and then melt extruded and foamed to obtain extruded polystyrene board substrate; S3. Preparation of anti-overflow adhesive: Mix water-based epoxy resin, polyurethane toughening agent and reactive diluent evenly, then add latent amine curing agent, and stir at 300-500 r / min for 15-25 min to obtain anti-overflow adhesive. S4. Applying anti-overflow adhesive layer and laying fiberglass mesh: Apply anti-overflow adhesive evenly to the upper and lower surfaces of the extruded board substrate layer to form the first anti-overflow adhesive layer and the second anti-overflow adhesive layer; then, within 3-5 minutes, lay alkali-resistant fiberglass mesh and compact it with a pressure roller with a pressure of 0.2-0.4 MPa, so that 1 / 3 to 1 / 2 of the thickness of the fiberglass mesh is embedded in the adhesive layer. S5. Coating and UV curing: Apply UV curing coating to the surface of the fiberglass mesh layer and cure it by irradiation with UV light with a wavelength of 365nm and a light intensity of 80-120mW / cm² for 30-60s. S6. Aging treatment: Place the composite board in a standard environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 7-10 days to age it.

[0016] Preferably, in step S2, the process parameters for melt extrusion are: zone 1 temperature 175-185℃, zone 2 temperature 180-190℃, zone 3 temperature 185-195℃, zone 4 temperature 190-200℃, and die temperature 185-195℃.

[0017] Preferably, in step S4, the pressure roller is a heated pressure roller, and the roller surface temperature is controlled at 40-60℃.

[0018] Preferably, in step S6, the aging process is carried out under constant ventilation conditions, with the wind speed controlled at 0.5-1.5 m / s.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention benefits from the high-efficiency thermal insulation network constructed by pretreated graphite and nano-nucleating agents, which significantly reduces the thermal conductivity of the board to 0.019-0.022 W / (m·K), and improves the thermal insulation efficiency by about 30% compared with traditional products, effectively reducing the energy consumption of grain silo cooling.

[0020] 2. Through multiple stabilization designs, the product's 28-day dimensional change rate is kept at an extremely low level of 0.05%-0.09%, less than 1 / 5 of that of traditional products, fundamentally eliminating the problems of board seam cracking and cold bridging caused by shrinkage.

[0021] 3. The present invention enables the plate to effectively distribute the load and thermal stress of the grain pile through the composite reinforcement structure. After thermal cycling test from -25℃ to 60℃, there was no bulging or cracking, demonstrating excellent adaptability to the harsh environment of the grain warehouse.

[0022] 4. This invention achieves a bonding strength of over 0.40 MPa between the product and inorganic mortar through an optimized interface layer, and the failure mode is more convincing cohesive failure of the substrate. Its water-resistant bonding strength exceeds 0.30 MPa, and the strength retention rate after accelerated aging is >98%, ensuring long-term reliability.

[0023] 5. The surface treatment layer of this invention eliminates the traditional interface agent application process, enabling immediate use. It adopts environmentally friendly foaming agents and halogen-free flame retardant systems throughout the process, eliminating harmful substances such as HBCD and meeting the requirements for green grain storage in grain warehouses. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the extruded polystyrene board structure of the present invention; Figure 2 This is a schematic diagram of the structure of the extruded polystyrene board and the grain storage wall of the present invention.

[0025] In the figure: 1. Extruded polystyrene board; 101. Extruded board substrate layer; 102. First anti-overflow adhesive layer; 103. First alkali-resistant fiberglass mesh layer; 104. First UV-curable coating; 105. Second anti-overflow adhesive layer; 106. Second alkali-resistant fiberglass mesh layer; 107. Second UV-curable coating. Detailed Implementation

[0026] Example 1: This invention provides a technical solution: a crack-resistant and heat-insulating extruded polystyrene board, comprising: An extruded polystyrene board 1 is bonded to the wall of a grain storage silo. The extruded polystyrene board 1 includes an extruded board substrate layer 101. Graphite particles pretreated with a silane coupling agent are uniformly dispersed inside the extruded board substrate layer 101. The top of the extruded board substrate layer 101 is sequentially laminated with a first anti-overflow adhesive layer 102, a first alkali-resistant fiberglass mesh layer 103, and a first UV-curable coating 104 from the inside out. The bottom of the extruded board substrate layer 101 is sequentially laminated with a second anti-overflow adhesive layer 105, a second alkali-resistant fiberglass mesh layer 106, and a second UV-curable coating 107 from the inside out. The raw materials of the extruded board substrate layer 101, by weight percentage, include: The composition includes 91% polystyrene resin, 4% graphite particles pretreated with KH-550, 3.2% environmentally friendly foaming agent, 1% nucleating agent, 0.5% composite antioxidant, and 0.3% ultraviolet absorber. The composite antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] as the primary antioxidant and tris(2,4-di-tert-butylphenyl) phosphite as the secondary antioxidant, in a mass ratio of 2:1 to 3:1. The environmentally friendly foaming agent is HFO-1336mzz, and the nucleating agent is nano-sized talc powder with a particle size D50 of 1-5 μm. The raw materials of the first anti-overflow adhesive layer 102 and the second anti-overflow adhesive layer 105, by weight percentage, include: Waterborne epoxy resin 60%, polyurethane toughening agent 20%, latent amine curing agent 16%, reactive diluent 4%; The coating thickness of the first anti-overflow adhesive layer 102 and the second anti-overflow adhesive layer 105 is 0.4 mm. The basis weight of the first alkali-resistant fiberglass mesh layer 103 and the second alkali-resistant fiberglass mesh layer 106 is 180 g / m², the mesh size is 4 mm × 4 mm, and their surfaces are coated with a wetting agent containing a silane coupling agent. Their alkali resistance retention rate is ≥95%, and their tensile strength is ≥1500 N / 50 mm. The raw materials of the first UV-curable coating 104 and the second UV-curable coating 107, by weight percentage, include: The composition includes 87% aliphatic polyurethane acrylate resin, 5% photoinitiator 1-hydroxycyclohexylphenyl ketone, 3% silane coupling agent KH-560, 1.5% leveling agent, and 0.5% defoamer. The dry film thickness of the first UV-curable coating 104 and the second UV-curable coating 107 is 0.2 mm.

[0027] Preparation steps of a crack-resistant and heat-insulating extruded polystyrene board: S1. Raw material pretreatment: 4 parts of graphite particles were added to 100 parts of 1.5wt% KH-550 ethanol solution, ultrasonically treated at 35kHz frequency for 30min, then filtered, and dried in an oven at 95℃ for 2h for later use. S2. Preparation of substrate: All the above substrate raw materials are put into a high-speed mixer and mixed at 450r / min for 12min. Then they are fed into a twin-screw extruder and the temperature zones are set as follows: Zone 1 180℃, Zone 2 185℃, Zone 3 190℃, Zone 4 195℃, and the die temperature is 190℃. After foaming, traction and cutting, a substrate with a thickness of 50mm is obtained. S3. Preparation and application of anti-overflow adhesive: Stir each component of the anti-overflow adhesive at 400r / min for 20min according to the ratio. In a clean room at 23℃ and 55% humidity, apply the adhesive evenly to the upper and lower surfaces of the substrate with a scraper, and control the thickness to 0.4mm. S4. Laying fiberglass mesh: Within 4 minutes after applying the adhesive, quickly lay the alkali-resistant fiberglass mesh, and then compact it with a roller heated to 50°C and with a pressure of 0.3MPa to ensure that about 40% of the thickness of the fiberglass mesh is embedded in the adhesive layer. S5, UV curing: Immediately apply UV curing coating to the surface of the fiberglass mesh, with a wet film thickness of 0.15mm, and then irradiate it for 45s through a 365nm UV curing machine (light intensity 100mW / cm²); S6. Controlled aging: Move the boards to a standard aging room (23℃, 50% humidity), place them on a support, and maintain a constant wind speed of 1.0m / s for ventilation and aging for 8 days.

[0028] Comparative Example 1 It uses commercially available ordinary XPS boards, without added graphite, any composite reinforcement layer, or surface treatment.

[0029] Comparative Example 2 The same basic formulation as in the example was used, but the graphite pretreatment and heated roller process were omitted (and replaced with room temperature rollers) to examine the individual contributions of these two key technologies.

[0030] Performance Comparison and Data Analysis Three sets of samples were sent to a third-party testing agency for performance testing according to national standards. The results are compared below: Test Project Test Standards Best Practice Comparative Example 1 Comparative Example 2 Thermal conductivity (W / m·K) GB / T10295 0.019 0.030 0.022 28-day dimensional change rate (%) GB / T8811 0.05 0.35 0.10 Tensile strength (MPa) GB / T29906 0.45㊟ 0.18 0.32 Water-resistant bond strength (MPa) JGJ / T144-2019 0.35 0.12 0.25 Thermal cycling stability -25℃ / 60℃, 30 cycles No abnormalities Severe bulging and cracking Slight bulging at the edges Long-term durability 70℃ / 95% humidity, 28 days 98% 75% 88% The failure mode is "cohesive failure of the substrate", meaning that the substrate itself is broken during the test, rather than the bonding interface falling off.

[0031] Based on the above comparative data, the following key conclusions can be drawn: Breakdown of core technology contributions: Example 1 - Comparative Example 1: The product of the present invention has achieved comprehensive superiority in thermal insulation performance (thermal conductivity reduced by 36%), dimensional stability (shrinkage rate reduced by 86%), interfacial bonding strength (increased by 150%), and long-term durability, proving the excellence of the entire technical solution.

[0032] Best Example - Comparative Example 2: Although the performance of Comparative Example 2 is better than that of the conventional product, it is significantly lower than that of the best example. This proves that graphite pretreatment and heated roller are two crucial technical know-hows. The former ensures the uniform dispersion and interfacial bonding of graphite, which is the key to achieving ultra-low thermal conductivity; the latter significantly improves the wetting and bonding force between the adhesive layer and the fiberglass mesh, which is the core to achieving high strength and high durability.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A crack-resistant and heat-insulating extruded polystyrene board, characterized in that, include: An extruded polystyrene board (1) is bonded to the wall of a grain storage silo. The extruded polystyrene board (1) includes an extruded board substrate layer (101). The extruded board substrate layer (101) contains graphite particles that have been pretreated with a silane coupling agent. The top of the extruded board substrate layer (101) is sequentially coated with a first anti-overflow adhesive layer (102), a first alkali-resistant fiberglass mesh layer (103), and a first ultraviolet curing coating layer (104) from the inside out. The bottom of the extruded board substrate layer (101) is sequentially coated with a second anti-overflow adhesive layer (105), a second alkali-resistant fiberglass mesh layer (106), and a second ultraviolet curing coating layer (107) from the inside out.

2. The crack-resistant and heat-insulating extruded polystyrene board according to claim 1, characterized in that, The raw materials of the extruded board substrate layer (101) include, by weight percentage: The composition includes 88-93% polystyrene resin, 2-5% pretreated graphite particles, 3-5% environmentally friendly foaming agent, 0.5-1.5% nucleating agent, 0.3-0.8% composite antioxidant, and 0.2-0.7% ultraviolet absorber. The composite antioxidant is composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] as the primary antioxidant and tris(2,4-di-tert-butylphenyl) phosphite as the secondary antioxidant in a mass ratio of 2:1 to 3:

1.

3. The extruded polystyrene board for crack resistance and heat insulation according to claim 2, characterized in that, The environmentally friendly foaming agent is HFO-1336mzz, and the nucleating agent is nano-sized talc powder with a particle size D50 of 1-5μm.

4. The extruded polystyrene board for crack resistance and heat insulation according to claim 1, characterized in that, The raw materials of the first anti-spill adhesive layer (102) and the second anti-spill adhesive layer (105) by weight percentage include: Waterborne epoxy resin 55-65%, polyurethane toughening agent 15-25%, latent amine curing agent 12-18%, reactive diluent 3-7%; The coating thickness of the first anti-overflow adhesive layer (102) and the second anti-overflow adhesive layer (105) is 0.3-0.5 mm.

5. The extruded polystyrene board for crack prevention and heat insulation according to claim 1, characterized in that, The first alkali-resistant fiberglass mesh layer (103) and the second alkali-resistant fiberglass mesh layer (106) have a basis weight of 160-200 g / m², a mesh size of 4 mm × 4 mm, and their surfaces are coated with a wetting agent containing silane coupling agent. Their alkali resistance retention rate is ≥92%, and their tensile strength is ≥1500 N / 50 mm.

6. The extruded polystyrene board for crack resistance and thermal insulation according to claim 1, characterized in that, The raw materials for the first UV-curable coating (104) and the second UV-curable coating (107) comprise, by weight percentage: The composition includes: 80-90% aliphatic polyurethane acrylate resin, 3-8% photoinitiator 1-hydroxycyclohexylphenyl ketone, 2-5% silane coupling agent KH-560, 0.5-2% leveling agent, and 0.5-1.5% defoamer. The dry film thickness of the first UV-curable coating (104) and the second UV-curable coating (107) is 0.1-0.2 mm.

7. A method for preparing the crack-resistant and heat-insulating extruded polystyrene board as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Raw material pretreatment: Place graphite particles in an ethanol solution of silane coupling agent KH-550 with a concentration of 1-2wt%, disperse ultrasonically for 20-40 minutes, filter, and dry at 80-100℃ to obtain pretreated graphite particles. S2. Preparation of extruded polystyrene board substrate: Polystyrene resin, pretreated graphite particles, foaming agent, nucleating agent, composite antioxidant and ultraviolet absorber are mixed according to the formula, and then melt extruded and foamed to obtain extruded polystyrene board substrate; S3. Preparation of anti-overflow adhesive: Mix water-based epoxy resin, polyurethane toughening agent and reactive diluent evenly, then add latent amine curing agent, and stir at 300-500 r / min for 15-25 min to obtain anti-overflow adhesive. S4. Applying anti-overflow adhesive layer and laying fiberglass mesh: Apply anti-overflow adhesive evenly to the upper and lower surfaces of the extruded board substrate (101) to form a first anti-overflow adhesive layer (102) and a second anti-overflow adhesive layer (105); then lay alkali-resistant fiberglass mesh within 3-5 minutes and compact it with a pressure roller with a pressure of 0.2-0.4 MPa, so that 1 / 3 to 1 / 2 of the thickness of the fiberglass mesh is embedded in the adhesive layer; S5. Coating and UV curing: Apply UV curing coating to the surface of the fiberglass mesh layer and cure it by irradiation with UV light with a wavelength of 365nm and a light intensity of 80-120mW / cm² for 30-60s. S6. Aging treatment: Place the composite board in a standard environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 7-10 days to age it.

8. The method for preparing a crack-resistant and heat-insulating extruded polystyrene board according to claim 7, characterized in that, In step S2, the process parameters for melt extrusion are as follows: temperature of zone 1 of the twin-screw extruder is 175-185℃, temperature of zone 2 is 180-190℃, temperature of zone 3 is 185-195℃, temperature of zone 4 is 190-200℃, and die temperature is 185-195℃.

9. The method for preparing a crack-resistant and heat-insulating extruded polystyrene board according to claim 7, characterized in that, In step S4, the pressure roller is a heated pressure roller, and the roller surface temperature is controlled at 40-60℃.

10. The method for preparing a crack-resistant and heat-insulating extruded polystyrene board according to claim 7, characterized in that, In step S6, the aging process is carried out under constant ventilation conditions, with the wind speed controlled at 0.5-1.5 m / s.

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