Polystyrene composite insulation board and preparation method thereof

Abstract

The application relates to the technical field of thermal insulation boards, and particularly discloses a polystyrene composite thermal insulation board and a preparation method thereof. The polystyrene composite thermal insulation board comprises the following proportions of raw materials: polystyrene 75-90 wt%; reinforcing material 5-10 wt%; nucleating agent 0.5-3 wt%; flame retardant 1-5 wt%; foaming agent 5-10 wt%; the foaming agent comprises any one or more of alcohol, CO2, R-152a, HFO-1233zd and HFO-1234ze. The preparation method comprises the following steps: S1, raw material preparation; and S2, thermal insulation board preparation. The composite thermal insulation board can be used for wall thermal insulation, and has the advantages of low thermal conductivity, high strength, stable foam holes and the like.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of thermal insulation boards, and more particularly to a polystyrene composite thermal insulation board and a preparation method thereof. BACKGROUND

[0002] Extruded polystyrene (XPS) foam is a kind of foam material prepared by using general-purpose polystyrene as raw material and adopting continuous extrusion foaming method. Due to its excellent thermal insulation performance, moisture resistance, high compressive strength, chemical corrosion resistance and convenient processability, the XPS foam is widely used in the fields of transportation, refrigeration, building and indoor decoration.

[0003] The existing XPS boards are mainly used in the field of thermal insulation, such as cold storage heat insulation and wall heat insulation indoors and outdoors. However, in some high-end fields such as wind power and rail transportation, the lower use temperature (0-75℃) and the side compressive strength of the XPS boards limit the expansion of the application field. SUMMARY

[0004] In order to improve the thermal insulation effect and the compressive effect of the polystyrene thermal insulation board, the application provides a polystyrene composite thermal insulation board and a preparation method thereof, which adopts the following technical scheme:

[0005] In the first aspect, the application provides a polystyrene composite thermal insulation board, which comprises the following proportions of raw materials:

[0006] Polystyrene 75-90wt%;

[0007] Reinforcing material 5-10wt%;

[0008] Nucleating agent 0.5-3wt%;

[0009] Flame retardant 1-5wt%;

[0010] Foaming agent 5-10wt%; the foaming agent comprises any one or more of alcohol, CO2, R-152a, HFO-1233zd and HFO-1234ze.

[0011] By adopting the above technical scheme, the application preferably adopts a foaming agent combination with multiple components and low thermal conductivity, which is beneficial to reducing the thermal conductivity while maintaining the strength of the composite thermal insulation board.

[0012] R-152a, HFO-1233zd and HFO-1234ze are all foaming agents with low thermal conductivity, which can reduce the foam density, increase the foam compressive strength, and make the pore size distribution uniform, thereby improving the thermal insulation effect and mechanical strength of the thermal insulation board.

[0013] Optionally, the foaming agent includes CO2, HFO-1233zd and R-152a in a mass ratio of 3.5:2.1:2.2.

[0014] By adopting the above technical solution, preferably, the multi-component low thermal conductivity foaming agent with appropriate proportion is adopted to cooperate with each other, CO2 is used as the main foaming agent, and 1233zd and 152 are used as the auxiliary foaming agent, CO2 can alleviate the problem of high brittleness of the foam, effectively reduce the thermal insulation coefficient of the composite insulation board, and make the insulation board obtain excellent thermal insulation effect.

[0015] Optionally, the reinforcing material includes any one or more of polyamide 6, ABS and PC.

[0016] By adopting the above technical solution, by adding the reinforcing material, the melt strength of the PS matrix is higher, which is more conducive to forming a stable cell structure in the cell growth process of the composite insulation board, and the composite insulation board obtains excellent compressive strength and hot deformation temperature.

[0017] Polyamide 6 can significantly enhance the compressive strength of XPS while maintaining the thermal conductivity coefficient unchanged, and simultaneously improve the side compressive strength. With the increase of the PA6 feeding amount, the compressive strength of the front and side surfaces also increases. The introduction of the reinforcing material can also increase the hot deformation temperature of XPS and increase the use temperature range. Therefore, the introduction of PA6 and other reinforcing materials can significantly increase the mechanical properties of XPS.

[0018] Optionally, the flame retardant includes any one or more of methyl octabromoether, siloxane and silicone rubber.

[0019] Optionally, the nucleating agent includes any one or more of talc, calcium carbonate and carbon black.

[0020] Optionally, the reinforcing material further includes straw fibers, and the straw fibers are straw / mycelium composite materials.

[0021] By adopting the above technical solution, the mycelium has a large number of mycelium and hollow tubular structure, the mycelium can combine with the straw fibers to form a super-dense linear network structure, and form a three-dimensional network structure, that is, the composite material has more pore structures, and after being added to the composite insulation board, the pore structure in the insulation board can be effectively improved, and the thermal conductivity of the insulation board is further reduced. The fiber structure can increase the nucleation sites in the insulation board, so that the insulation board obtains excellent foaming effect and cell stability.

[0022] Optionally, the preparation of the straw / mycelium composite material is as follows: the straw fibers are immersed in an alkali solution, immersed, filtered, washed, dried, and the pretreated straw fibers are obtained; the pretreated straw fibers, bran, glucose, calcium carbonate, magnesium sulfate, and mushroom enzyme are mixed to obtain a culture medium; the mycelium balls are inoculated into the culture medium, cultured, compacted, demolded, and dried to obtain the straw / mycelium composite material.

[0023] By adopting the above technical solution, the straw fibers are preferably pretreated with an alkali solution, which can destroy the internal structure of the straw fibers, increase the specific surface area of the straw fibers, provide a good growth interface for the mycelium, promote the growth of the mycelium, and make the mycelium and the straw fibers tightly combined, so that the composite material has excellent mechanical effect. Moreover, the alkali treatment can increase the content of hydrophobic protein in the mycelium, thereby effectively improving the hydrophobic effect of the composite material.

[0024] Optionally, the straw / mycelium composite material is a straw / mycelium composite material wrapped with oleic acid and magnesium hydroxide.

[0025] By adopting the above technical solution, the composite material is wrapped with oleic acid and magnesium hydroxide. The oleic acid can be combined with the hydroxyl groups in the magnesium hydroxide, thereby grafting long-chain groups on the surface of the composite material, and improving the polarity and hydrophobic effect of the composite material, and improving the compatibility and combination effect between the composite material and polystyrene. Moreover, the wrapping of magnesium hydroxide can make the composite material have a rough surface and excellent flame retardant effect, and can improve the bonding strength between the composite material and polystyrene, and further improve the flame retardancy and mechanical strength of the composite insulation board.

[0026] In a second aspect, the application provides a preparation method of a polystyrene composite insulation board, which adopts the following technical solution:

[0027] A preparation method of a polystyrene composite insulation board, comprising the following steps:

[0028] S1, raw material preparation: polystyrene, reinforcing material, nucleating agent, flame retardant, and foaming agent are weighed according to weight parts;

[0029] S2, preparation of the insulation board: the polystyrene, reinforcing material, nucleating agent, and flame retardant are added to a first-stage extruder, mixed, the foaming agent is injected from a foaming agent injection port, mixed, extruded, conveyed to a second-stage extruder through a screen changer, stirred, mixed, molded, and cut to obtain the composite insulation board.

[0030] Optionally, the screen changer is a replaceable screen changer system.

[0031] By adopting the above technical scheme, since the replaceable screen changing system is adopted, the screen changer can replace the iron wire mesh and clean the large impurities on the iron wire mesh after running for a period of time, thereby reducing the influence of screen changer blockage on the production efficiency of the composite insulation board.

[0032] Optionally, the second-order extruder is a single-screw extruder.

[0033] By adopting the above technical scheme, preferably, the single-screw extruder is used as the second-order extruder, and the single-screw extruder can cool the homogeneous melt with greatly reduced melt strength after plasticization of the foaming agent, so as to improve the melt strength and reach the required viscosity range of the formed product.

[0034] In summary, the present application has the following beneficial effects:

[0035] 1. The present application uses blended reinforcing materials to reinforce the PS matrix, which is beneficial to improve the compressive strength and heat distortion temperature;

[0036] 2. The present application uses a multi-component low-thermal-conductivity foaming agent combination, which is beneficial to reduce the thermal conductivity while maintaining the strength;

[0037] 3. The present application uses a PS matrix melt with higher melt strength after blending modification, which is more beneficial to stabilize the cell structure during cell growth;

[0038] 4. The introduction of the multi-component foaming agent is beneficial to the nucleation and growth of the cells. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a flowchart of the method provided by the present application. DETAILED DESCRIPTION

[0040] The present application will be further described in detail below in combination with examples.

[0041] Preparation Example

[0042] Composite Material Preparation Example

[0043] Preparation Example 1

[0044] Alkaline solution preparation: mix urea, sodium hydroxide and water to obtain an alkaline solution with a urea concentration of 10wt% and a sodium hydroxide concentration of 6wt%.

[0045] Soil fiber is immersed in the alkaline solution at 80℃ and a rotation speed of 150rpm for 30min, filtered, washed and dried to obtain pretreated straw fiber.

[0046] Preparation of Pleurotus ostreatus medium: 20 g of corn flour, 2 g of peptone, 0.5 g of MgS04·7H20, 1 g of KH2P04, 0.1 g of NaCl and 200 g of potatoes were mixed to obtain the Pleurotus ostreatus medium.

[0047] Preparation of PDA: 200 g of potatoes, 20 g of glucose, 5 g of peptone, 2 g of agar, 1.5 g of MgS04·7H20 and 3 g of KH2P04 were mixed to obtain PDA.

[0048] Preparation of mycelium medium: 60 g of straw fiber, 7.5 g of bran, 2.8 g of glucose, 0.75 g of calcium carbonate, 0.1875 g of MgS04·7H20, 0.2 g of mushroom enzyme and distilled water were mixed to obtain the mycelium medium (water content 70%).

[0049] The sterilized PDA was placed in an ultraclean workbench, poured into a flat plate, and then sterilized with ultraviolet light for 15 min. The Pleurotus ostreatus 1103 mother strain was placed in an ultraclean workbench, punched into a 0.9 cm diameter fungus cake with a fungus cake puncher, and inoculated into the PDA flat plate with an inoculation hook. The Pleurotus ostreatus 1103 after subculture was placed in a constant temperature incubator at a temperature of 28°C and a relative humidity of 60% for 7 days. After the mycelium grew over the flat plate, it was taken out and stored in a 4°C refrigerator for standby use.

[0050] The sterilized Pleurotus ostreatus medium and the Pleurotus ostreatus 1103 flat plate after subculture were placed in an ultraclean workbench. The fungus cake puncher punched the second generation strain into a 0.9 cm diameter fungus cake, and three fungus cakes were picked out with an inoculation hook and inoculated into 100 mL of Pleurotus ostreatus liquid medium.

[0051] The inoculated Pleurotus ostreatus 1103 was placed in a 28°C, 160 r / min shaker for 7 days to obtain mycelium balls, which were taken out and stored in a 4°C refrigerator for standby use. The Pleurotus ostreatus 1103 mycelium balls were filtered, and 20 g of the sterilized mycelium material medium was inoculated with a 15% mass fraction of the Pleurotus ostreatus mycelium balls, and then stirred uniformly with a glass plate and loaded into a cylindrical glass mold. The mycelium material was placed in a culture box for dark culture, and every 7 days, it was taken out and pressed to 5 cm. After the mycelium material was cultured in a constant temperature incubator for 16 days, it was taken out and demolded. The demolded material was dried in a 60°C oven for 24 h, broken, and then a straw / mycelium composite material was obtained.

[0052] Preparation Example 2

[0053] In the container, 2 g of straw / mycelium composite material and 50 mL of 0.5 mol / L MgCl2·6H2O solution were added, and after being uniformly dispersed, the digital stirrer was opened, 53 mL of 1 mol / L NaOH solution was added dropwise into the container, the pH value was adjusted to about 9, and after the dropwise addition was completed, it was moved into a 85°C water bath, and reacted for 1 h. Then 3.5 mL of oleic acid (OA) was added, and the reaction was continued for 2 h. After the reaction was completed, it was cooled, filtered, washed with water until neutral, washed with anhydrous ethanol, and the filter cake was obtained, frozen and dried, and broken to obtain the modified straw / mycelium composite material. Embodiment

[0054] Embodiments 1-4

[0055] In one aspect, the present application provides a polystyrene composite insulation board, which comprises polystyrene, reinforcing material, nucleating agent, flame retardant and foaming agent, and the specific mass is shown in the following table.

[0056] Specifically, the polystyrene is general-purpose polystyrene, the reinforcing material is PA6, the nucleating agent is talc, the flame retardant is methyl octabromoether, and the foaming agent is carbon dioxide, HFO-1233zd and R-152a.

[0057]

[0058] In another aspect, the present application provides a preparation method of a polystyrene composite insulation board, which comprises the following steps:

[0059] S1, raw material preparation: polystyrene, reinforcing material, nucleating agent, flame retardant and foaming agent were weighed according to the weight fraction;

[0060] S2, insulation board preparation: polystyrene, reinforcing material, nucleating agent and flame retardant were added to a first-stage extruder, mixed, the foaming agent was injected from a foaming agent injection port, mixed, extruded, conveyed to a second-stage extruder through a screen changer, stirred, mixed, molded, cut, and a composite insulation board was obtained.

[0061] Specifically, step S2, insulation board preparation, comprises:

[0062] S21, polystyrene, reinforcing material, nucleating agent and flame retardant were added to a first-stage extruder (double-screw extruder), and the temperature of each zone of the double-screw extruder was set to 200-230°C;

[0063] Among them: from the discharge port to the front of the foaming agent injection port, it is mainly a strong shearing section, which is used to mix the material sufficiently and uniformly.

[0064] S22, the foaming agent was continuously and stably injected into the double-screw extruder from the foaming agent injection port through a foaming agent metering pump, mixed, and a mixed melt was obtained;

[0065] Wherein: the foaming agent injection state should be liquid, and should be pressurized before injection to prevent gas backflow, the injection position is where the polystyrene, reinforcing material, nucleating agent and flame retardant components are uniformly mixed, the screw at the injection position is designed with multiple protrusions to prevent the formation of liquid pools and promote the rapid dispersion of gas in the melt, and the barrel temperature is set to 200-210°C due to the decrease in melt strength caused by the plasticization of the foaming agent to the melt.

[0066] S23, the mixed melt passes through the screen changer to filter out large impurities, and is conveyed to the second-stage extruder (single screw extruder) through the melt conveying pipeline,

[0067] Wherein: the single screw extruder can cool the homogeneous melt whose strength has been greatly reduced after being plasticized by the foaming agent, so as to increase the melt strength and reach the required viscosity range of the shaped product;

[0068] The screen changer uses a replaceable screen system, which is replaced and cleaned after a certain period of operation to reduce the impact on production efficiency;

[0069] The melt conveying pipeline does not contain a screw, and the barrel temperature is set to 180-200°C;

[0070] The single screw extruder adopts a stepwise cooling mode from the front to the head to sufficiently cool the melt, and the temperature of each zone is set to 90-140°C. The single screw speed should not be too fast to prevent the screw from shearing and heating the melt. The melt cooling rate should be efficient and rapid. A static mixer or melt pump device is arranged before the head of the single screw to control and maintain the pressure of the melt and prevent premature pressure relief of the melt from causing pre-foaming. The static mixer temperature should be appropriately increased, generally set to 110-130°C, to prevent the melt from flowing and stagnating in this area.

[0071] S24, after cooling, the homogeneous melt passes through the head and the die lip, and due to the rapid pressure relief, the thermodynamic steady state is broken, the foaming agent gas quickly escapes from the polymer, causing the melt to expand in volume and form a closed cell structure. After that, the XPS is sized by a sizing template, a whole platform, and a traction roller;

[0072] Wherein: the design of the head flow channel needs to ensure that the melt flow rate at each position of the die lip is equivalent, as the pressure drop distribution in each zone of the die is calculated on the premise of controlling the total pressure drop of the melt; the traction roller speed is matched with the melt extrusion amount at the die mouth to ensure that the stretching force received by the plate in the transverse direction is consistent.

[0073] S25, after sizing, the flat XPS plate is cut by a cutter to remove a little edge material on both sides, then is sprayed with codes on the side edges and embossed on the front and back surfaces, and then is cut into slices by a transverse cutting machine, packaged and stored to obtain a composite insulation board.

[0074] Table 1 Example 1

[0075]

[0076] Example 5

[0077] The difference from Example 4 is that the reinforcing material comprises PA6 and the straw / mycelium composite material prepared in Preparation Example 1 at a mass ratio of 7:3.

[0078] Example 6

[0079] The difference from Example 3 is that the reinforcing material comprises PA6 and the straw / mycelium composite material prepared in Preparation Example 1 at a mass ratio of 7:3. Comparative Example

[0080] Comparative Example 1

[0081] The difference between the present comparative example and Example 4 is that no reinforcing material is added in the present comparative example.

[0082] Performance detection test

[0083] (1) Apparent density test: The test was performed according to the test method of GB / T6343-1996 "Determination of apparent (bulk) density of foamed plastics and rubbers".

[0084] (2) Thickness detection: The thickness of the insulation board was measured with a ruler.

[0085] (3) Compression strength test: The 10% compression strength and side compression strength of the insulation board were tested according to GB / T8813-1998 "Hard foamed plastics - Compression test methods".

[0086] (4) Heat deformation detection: The heat deformation temperature of the insulation board was tested using a heat deformation Vicat softening point tester.

[0087] (5) Thermal conductivity detection: The thermal conductivity equipment was determined using FOX200 produced by TA Instruments, USA.

[0088] (6) Combustion performance test: The combustion performance grade of the insulation board was tested according to GB / T 10801.2-2018 "Extruded polystyrene foam for thermal insulation".

[0089] Table 2 Performance detection

[0090]

[0091] It can be found from the comparison of Table 2 performance detection that:

[0092] 1、Comparing with Example 1-4 and Comparative Example 1, it can be found that the apparent density, compressive strength and heat distortion temperature of the thermal insulation board prepared in Example 1-4 are improved, and the thermal conductivity is reduced, which shows that the introduction of PA6 in the present application can significantly enhance the compressive strength of XPS while maintaining the thermal conductivity unchanged, and at the same time improve the side compressive strength. And with the increase of the amount of PA6, the compressive strength of the front and side also increases. The introduction of reinforcing materials can also improve the heat distortion temperature of XPS and increase its use temperature range. Therefore, the introduction of reinforcing materials such as PA6 can significantly increase the mechanical properties of XPS.

[0093] 2、Comparing with Example 5-6 and Example 4, it can be found that the apparent density, compressive strength and heat distortion temperature of the thermal insulation board prepared in Example 1-4 are improved, and the thermal conductivity is reduced, which shows that the mycelium in the present application has a large amount of mycelium and hollow tubular structure, and the composite material has a three-dimensional network structure and more pore structure, which can introduce hollow heat insulation structure and fiber structure into the thermal insulation board, effectively improve the thermal insulation effect and mechanical strength of the thermal insulation board. By wrapping the composite material with oleic acid and magnesium hydroxide, flame-retardant groups and long-chain groups can be introduced on the surface of the composite material, thereby improving the polarity, hydrophobicity and flame-retardant effect of the composite material, and improving the compatibility and bonding effect between the composite material and polystyrene.

[0094] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A polystyrene composite insulation board, characterized in that, Including the following proportions of raw materials: Polystyrene 75-90 wt% 5-10 wt% of reinforcing material; Nucleating agent 0.5-3 wt%; Flame retardant 1-5wt%; 5-10 wt% foaming agent; the foaming agent comprises CO2, HFO-1233zd and R-152a in a mass ratio of 3.5:2.1:2.2; The reinforcing material includes straw fiber, which is a modified straw / mycelium composite material; The preparation of straw / mycelium composite material is as follows: straw fibers are impregnated in alkaline solution, impregnated, filtered, washed, and dried to obtain pretreated straw fibers; A culture medium was prepared by mixing pretreated straw fiber, wheat bran, glucose, calcium carbonate, magnesium sulfate, mushroom-enhancing enzyme, and water. Mycelial balls were inoculated into the culture medium, cultured, compacted, demolded, and dried to obtain a straw / mycelial composite material. The alkaline solution is prepared by mixing urea, sodium hydroxide and water to obtain an alkaline solution with a urea concentration of 10 wt% and a sodium hydroxide concentration of 6 wt%. The specific operations of compaction, demolding, and drying include: filtering the oyster mushroom mycelium balls, inoculating them with 15% by weight of oyster mushroom mycelium balls in a sterilized mycelium material culture medium, stirring them evenly with a glass plate, and then filling them into a cylindrical glass mold. A cylindrical glass mold containing mycelial material was placed in an incubator for dark incubation. Every 7 days, the mold was removed and pressed to 5 cm. The mycelial material was incubated in a constant temperature incubator for 16 days and then removed from the mold. The removed material was dried in a 60℃ oven for 24 hours and then crushed to obtain a straw / mycelial composite material. The preparation methods for modified straw / mycelium composite materials include: Add 2g of straw / mycelium composite material and 50mL of 0.5mol / L MgCl2·6H2O solution to a container. After dispersing evenly, turn on the digital display stirrer and add 53mL of 1mol / L NaOH solution dropwise to the container. Adjust the pH value to 9. After the addition is complete, transfer the container to an 85℃ water bath and react for 1h. Then add 3.5mL of oleic acid and continue the reaction for 2h. After the reaction is complete, cool and filter, wash with water until neutral, wash with anhydrous ethanol to obtain filter cake, freeze dry, crush, and obtain modified straw / mycelium composite material.

2. The polystyrene composite insulation board according to claim 1, characterized in that: The reinforcing material includes any one or more of polyamide 6, ABS, and PC.

3. The polystyrene composite insulation board according to claim 1, characterized in that: The flame retardant includes any one or more of methyl octabromoether, siloxane, and silicone rubber.

4. The polystyrene composite insulation board according to claim 1, characterized in that: The nucleating agent includes any one or more of talc, calcium carbonate, and carbon black.

5. A polystyrene composite insulation board according to claim 1, characterized in that: The straw / mycelium composite material is a straw / mycelium composite material treated with oleic acid and magnesium hydroxide.

6. A method for preparing a polystyrene composite insulation board according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Raw material preparation: Weigh out polystyrene, reinforcing material, nucleating agent, flame retardant and foaming agent according to the weight parts; S2. Preparation of insulation board: Polystyrene, reinforcing material, nucleating agent and flame retardant are added to the first-stage extruder and mixed. The foaming agent is injected through the foaming agent injection port, mixed evenly, extruded, and conveyed to the second-stage extruder through the screen changer. The mixture is stirred, mixed evenly, molded, and cut to obtain the composite insulation board.

7. The method for preparing a polystyrene composite insulation board according to claim 6, characterized in that: The network switcher uses a replaceable network switching system.

8. The method for preparing a polystyrene composite insulation board according to claim 6, characterized in that: The second-stage extruder is a single-screw extruder.

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