A kind of building thermal insulation sandwich foam material and preparation method thereof

Abstract

The present invention relates to the technical fields of efficient utilization of agricultural and forestry biomass resources and green energy-saving building materials, and discloses a building insulation sandwich foam material and a preparation method thereof. The present invention utilizes agricultural and forestry biomass resources such as corn cobs, converts them through alkaline hydrolysis to form alkali lignin and polysaccharides with good toughening and cross-linking reaction activity, and then copolymerizes them with phenol and formaldehyde solutions to produce a high-solids foaming resin. The resin is then blended and foamed with phase change microcapsules to prepare a building sandwich foam material. The preparation method of the present invention increases the toughness of the foam material, overcomes defects such as high brittleness and easy surface pulverization of the foam material, improves the compressive strength of the foam material, and enhances the heat storage and release capacity of the foam material in a temperature alternating environment, thereby giving the foam material excellent self-insulating properties.

Description

Technical Field

[0001] The invention relates to a building thermal insulation sandwich foam material and a preparation method thereof, and belongs to the field of efficient utilization of agricultural and forestry biomass resources and green energy-saving building materials. Background Art

[0002] Rigid foam plastics are lightweight, inexpensive, dimensionally stable, and provide excellent thermal insulation. They are widely used as sandwich materials for roofing and wall enclosures in industrial plants, simple buildings, and mobile homes. Commonly used rigid foam plastics include polystyrene foam, rigid polyurethane foam, and phenolic foam, with an annual production exceeding 2.5 million tons. All three foam plastics offer excellent thermal insulation and sound absorption properties. Polystyrene foam is less expensive, but its thermal insulation performance is significantly affected by ambient humidity. Rigid polyurethane foam offers stable thermal insulation and excellent adhesion to other materials, but is more expensive. Both have a combustion oxygen index of around 26%. In comparison, phenolic foam has a combustion oxygen index of up to 50% and a smoke density rating of 4. Its heat resistance and flame retardancy are far superior to polyurethane and other foam plastics. It is non-flammable and does not melt or drip in air, and can withstand long-term use at temperatures up to 200°C. Its cost is only about two-thirds that of rigid polyurethane foam.

[0003] But phenolic foam is brittle and easy to pulverize and fall off on the surface, thereby is affected by the bonding property of other materials, and the intensity of phenolic foam needs to be further improved in addition.The fundamental reason that there is above-mentioned shortcoming in phenolic foam is that the benzene ring structure rotational freedom linked by methylene group is little, steric hindrance is large, and the benzene ring density height causes phenolic foam hard brittleness large.Publication number is that the patent of CN113321842A discloses a kind of preparation method of phenolic resin foam composite material, by foaming together with expandable phenolic resin material with mesh cloth and prepare phenolic resin foam composite material, this composite material is with mesh cloth as skeleton, greatly improved the intensity of phenolic foam board, flame retardant property is constant, but this method can't guarantee that foam material has excellent heat storage and release capacity under temperature alternating environment when not reducing its compressive strength and toughness. Summary of the Invention

[0004] The present invention aims to overcome the shortcomings of the prior art by providing a building insulation sandwich foam material and its preparation method. The preparation method of the present invention increases the toughness of the foam material, overcomes defects such as brittleness and surface pulverization, improves the foam material's compressive strength, and enhances its heat storage and release capacity in temperature-switching environments, thereby endowing the foam material with excellent self-insulating properties.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a building thermal insulation sandwich foam material comprises the following steps:

[0007] S1: Pour purified water and caustic soda into the reactor, stir, add biomass powder, heat to 70-90℃, stir and react for 20-40 minutes, and then cool to 45-60℃;

[0008] S2: inject molten phenol and formaldehyde solution into the reactor, react at 50-60°C for 30-40 minutes, then raise the temperature to 80-95°C and continue the reaction for 60-90 minutes;

[0009] S3: Add PEG 400 to the reactor, stir, cool to 70-75°C, vacuum dehydrate, cool to 0-35°C, discharge, and prepare biomass-modified foamable phenolic resin;

[0010] S4: injecting the above-mentioned biomass-modified foamable phenolic resin into a container, adjusting the pH to 3.5-5.5 with acid, and sequentially adding a surfactant, a curing accelerator, a foaming agent, and a phase change microcapsule, and stirring;

[0011] S5: injecting the material obtained in S4 into a mold with a non-woven fabric on the bottom, covering the non-woven fabric on the top, and placing it into a hot press to foam, take it out and cool it to make a building insulation sandwich foam material.

[0012] Preferably, the mass ratio of the purified water, caustic soda, and biomass powder is 100:(20-40):(5-20); the molecular weight ratio of the phenol, formaldehyde, and caustic soda is 1:(1.47-2.12):(0.15-0.4); and the mass ratio of the phenol and PEG 400 is 100:(5-30).

[0013] Preferably, the biomass powder in step S1 is one or more of corn cob powder, coconut shell powder, grapefruit peel powder, and oil tea peel powder, and the fineness of the biomass powder is above 180 mesh.

[0014] Preferably, the concentration of the formaldehyde solution in step S2 is 37-37.5%.

[0015] Preferably, the vacuum dehydration time in step S3 is 40-90 min.

[0016] Preferably, the acid in step S4 is p-toluenesulfonic acid and phosphoric acid, with a mass ratio of 100:(50-100).

[0017] Preferably, the surfactant in step S4 is a mixture of Tween-80 and OP-10, the mass ratio of the two is 1:1, and the amount used is 3%-8% of the mass of the foaming resin; the curing accelerator is one or both of zinc chloride and calcium chloride, and the amount used is 2%-5% of the mass of the foaming resin.

[0018] Preferably, the foaming agent in step S4 is n-pentane, and its usage is 5%-15% of the mass of the foaming resin; the phase change material of the phase change microcapsule is n-octadecane, and the wall material is one or more of melamine resin, methyl methacrylate or acrylic resin, and the usage of the phase change microcapsule is 2%-10% of the mass of the foaming resin.

[0019] Preferably, the foaming temperature in step S5 is 70-95° C., and the foaming time is 30-50 min.

[0020] A building thermal insulation sandwich foam material is prepared by adopting the above-mentioned preparation method.

[0021] The beneficial effects achieved by the present invention are:

[0022] (1) Biomass materials with low lignin content and high hemicellulose content are used to form alkaline lignin and polysaccharides with good toughening and cross-linking reaction activity through alkaline hydrolysis, which are further copolymerized with phenol, formaldehyde solution, and polyethylene glycol to produce a foaming resin with a high solid content. This significantly improves the rheological properties of the resin, improves the foaming ability of the resin, increases the toughness of the foam material, and overcomes the defects of the foam material such as high brittleness and easy surface pulverization.

[0023] (2) Phase change energy storage capsules with good compatibility are added to the foaming resin, and Lewis acids such as zinc chloride are used as curing accelerators to increase the cross-linking probability of the ortho-functional groups of the benzene ring, significantly improve the compressive strength of the foam material, and enhance the heat storage and release capacity of the foam material in a temperature alternating environment, thereby giving the foam material excellent self-insulation properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an SEM image of the building thermal insulation sandwich foam material prepared in Example 1;

[0025] Figure 2 This is an SEM image of the phenolic foam material prepared in Comparative Example 1;

[0026] Figure 3 This is a partially enlarged SEM image of the building thermal insulation sandwich foam material prepared in Example 1. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0028] Example 1

[0029] A method for preparing a building thermal insulation sandwich foam material comprises the following steps:

[0030] Step 1: Pour 1000g of purified water into the reactor, slowly add 212g of caustic soda, stir, and after the caustic soda is completely dissolved, add 100g of corn cob powder with a fineness of 200 mesh, heat to 80℃, stir and react for 40min;

[0031] Step 2: Cool to 55°C, inject 1992.8g of molten phenol, and stir for 15 minutes; inject 2595.6g of 37% formaldehyde solution, react at 55°C for 30 minutes, heat to 85°C, and continue the reaction for 60 minutes;

[0032] Step 3: Add 300g of PEG400, cool to 70°C under stirring, and vacuum dehydrate for 60 minutes; cool to below 35°C, discharge the material, and prepare a biomass-modified foamable phenolic resin;

[0033] Step 4: Prefabricate a frame mold with a length of 500 mm, a width of 400 mm, and a height of 50 mm, place the mold on a stainless steel pad, lay a layer of non-woven fabric on the bottom of the mold, and apply a release agent to the inner wall of the mold; weigh 700 g of the biomass-modified foamable phenolic resin prepared in step 3, pour it into a rapidly stirred container, adjust the pH value to 5.0 with a mixed acid prepared by mixing p-toluenesulfonic acid and phosphoric acid in a mass ratio of 1: 1, and add 35 g of a surfactant (Tween-80 and OP-10 are mixed in a mass ratio of 1: 1) in sequence, 28 g of a curing accelerator zinc chloride, 70 g of a n-pentane foaming agent, and 56 g of n-octadecane phase change microcapsules in proportion, and stir rapidly;

[0034] Step 5: Pour the evenly stirred material into the mold, lay it evenly, cover it with a layer of non-woven fabric, and cover the mold with a stainless steel pressing plate covered with exhaust holes; then send the whole into a preheated drying oven, foam it at 75°C for 40 minutes, take it out and cool it to make a building insulation sandwich foam material.

[0035] Step 6: Use SEM to observe the building insulation sandwich foam material. The results are as follows: Figure 1 As shown in the picture, there is less debris on the surface of the sample, indicating that the foam has good flexibility. Figure 3 This is a partially enlarged SEM image of the building thermal insulation sandwich foam material prepared in Example 1. The red circled part of the image is the phase change microcapsule particles.

[0036] Example 2

[0037] A method for preparing a building thermal insulation sandwich foam material comprises the following steps:

[0038] Step 1: Pour 1000g of caustic soda solution with a concentration of 17.5% into the reactor, add 150g of 200-mesh camellia peel powder, heat to 75°C and stir to react for 40 minutes;

[0039] Step 2: Cool to 50°C, inject 1880g of molten phenol, and stir for 15 minutes; inject 2400g of 37.5% formaldehyde solution, react at 58°C for 30 minutes, heat to 85°C, and continue the reaction for 60 minutes;

[0040] Step 3: Add 250g of a certain amount of PEG400, cool to 70°C under stirring, and vacuum dehydrate for 60 minutes; cool to below 35°C, discharge the material, and prepare a biomass-modified foaming phenolic resin;

[0041] Step 4: Prefabricate a frame mold with a length of 500 mm, a width of 400 mm, and a height of 50 mm, place the mold on a stainless steel pad, lay a layer of non-woven fabric on the bottom of the mold, and apply a release agent to the inner wall of the mold; weigh 800 g of the biomass-modified foamable phenolic resin prepared in step 3, pour it into a rapidly stirred container, adjust the pH value to 5.0 with a mixed acid prepared by mixing p-toluenesulfonic acid and phosphoric acid in a mass ratio of 1:1, and add 38 g of a surfactant (Tween-80 and OP-10 are mixed in a mass ratio of 1:1) in sequence, 25 g of a curing accelerator zinc chloride, 75 g of a n-pentane foaming agent, and 50 g of n-octadecane phase change microcapsules in proportion, and stir rapidly;

[0042] Step 5: Pour the evenly stirred material into the mold, lay it evenly, cover it with a layer of non-woven fabric, and cover the mold with a stainless steel pressing plate covered with exhaust holes; then send the whole into a preheated drying oven, foam it at 75°C for 40 minutes, take it out and cool it to make a building insulation sandwich foam material.

[0043] Example 3

[0044] A method for preparing a building thermal insulation sandwich foam material comprises the following steps:

[0045] Step 1: Pour 1000g of 20% caustic soda solution into the reactor, add 100g of 300-mesh coconut shell powder, heat to 90°C and stir to react for 40 minutes;

[0046] Step 2: Cool to 60°C, inject 1880g of molten phenol, and stir for 15 minutes; inject 2400g of 37.5% formaldehyde solution, react at 60°C for 30 minutes, heat to 90°C, and continue the reaction for 60 minutes;

[0047] Step 3: Add 200g of PEG400, cool to 70°C under stirring, and vacuum dehydrate for 60 minutes; cool to below 35°C, discharge the material, and prepare a biomass-modified foamable phenolic resin;

[0048] Step 4: Prefabricate a frame mold with a length of 500 mm, a width of 400 mm, and a height of 50 mm, place the mold on a stainless steel pad, lay a layer of non-woven fabric on the bottom of the mold, and apply a release agent to the inner wall of the mold; weigh 600 g of the biomass-modified foamable phenolic resin prepared in step 3, pour it into a rapidly stirred container, adjust the pH value to 5.0 with a mixed acid prepared by mixing p-toluenesulfonic acid and phosphoric acid in a mass ratio of 1:1, and add 32 g of a surfactant (Tween-80 and OP-10 mixed in a mass ratio of 1:1) in sequence, 26 g of a curing accelerator zinc chloride, 65 g of a n-pentane foaming agent, and 52 g of n-octadecane phase change microcapsules in proportion, and stir rapidly;

[0049] Step 5: Pour the evenly stirred material into the mold, lay it evenly, cover it with a layer of non-woven fabric, and cover the mold with a stainless steel pressing plate covered with exhaust holes; then send the whole into a preheated drying oven, foam it at 75°C for 40 minutes, take it out and cool it to make a building insulation sandwich foam material.

[0050] Comparative Example 1

[0051] A method for preparing a phenolic foam material comprises the following steps:

[0052] Step 1: Prefabricate a frame mold with a length of 500 mm, a width of 400 mm, and a height of 50 mm, place the mold on a stainless steel pad, lay a layer of non-woven fabric on the bottom of the mold, and apply a release agent on the inner wall of the mold; weigh 800 g of commercially purchased phenolic foam resin, pour it into a rapidly stirring container, adjust the pH value to 5.0 with a mixed acid prepared by mixing p-toluenesulfonic acid and phosphoric acid in a mass ratio of 1:1, add 35 g of a surfactant (Tween-80 and OP-10 mixed in a mass ratio of 1:1) and 75 g of a n-pentane foaming agent in proportion, and stir rapidly and evenly;

[0053] Step 2: Pour the evenly stirred material into the mold, lay it evenly, cover it with a layer of non-woven fabric, and cover the mold with a stainless steel pressing plate covered with exhaust holes; then send the whole into a preheated drying oven, foam it at 75°C for 40 minutes, take it out and cool it to make a phenolic foam material.

[0054] The phenolic foam material was observed using SEM. Figure 2 As shown in the picture, there are many debris on the surface of the sample, indicating that the foam is relatively brittle.

[0055] Comparative Example 2

[0056] A method for preparing a building thermal insulation sandwich foam material comprises the following steps:

[0057] Step 1: Pour 1000g of purified water into the reactor, slowly add 212g of caustic soda, stir, and after the caustic soda is completely dissolved, add 100g of corn cob powder with a fineness of 200 mesh, heat to 80℃, stir and react for 40min;

[0058] Step 2: Cool to 55°C, inject 1992.8g of molten phenol, and stir for 15 minutes; inject 2595.6g of 37% formaldehyde solution, react at 55°C for 30 minutes, heat to 85°C, and continue the reaction for 60 minutes;

[0059] Step 3: cooling to 70°C under stirring conditions, vacuum dehydration for 60 minutes; cooling to below 35°C, discharging the material, and preparing a biomass-modified foaming phenolic resin;

[0060] Step 4: Prefabricate a frame mold with a length of 500 mm, a width of 400 mm, and a height of 50 mm, place the mold on a stainless steel pad, lay a layer of non-woven fabric on the bottom of the mold, and apply a release agent to the inner wall of the mold; weigh 700 g of the biomass-modified foamable phenolic resin prepared in step 3, pour it into a rapidly stirred container, adjust the pH value to 5.0 with a mixed acid prepared by mixing p-toluenesulfonic acid and phosphoric acid in a mass ratio of 1: 1, and add 35 g of a surfactant (Tween-80 and OP-10 are mixed in a mass ratio of 1: 1) in sequence, 28 g of a curing accelerator zinc chloride, 70 g of a n-pentane foaming agent, and 56 g of n-octadecane phase change microcapsules in proportion, and stir rapidly;

[0061] Step 5: Pour the evenly stirred material into the mold, lay it evenly, cover it with a layer of non-woven fabric, and cover the mold with a stainless steel pressing plate covered with exhaust holes; then send the whole into a preheated drying oven, foam it at 75°C for 40 minutes, take it out and cool it to make a building insulation sandwich foam material.

[0062] Comparative Example 3

[0063] A method for preparing a building thermal insulation sandwich foam material comprises the following steps:

[0064] Step 1: Pour 1000g of purified water into the reactor, slowly add 212g of caustic soda, stir, and after the caustic soda is completely dissolved, add 100g of corn cob powder with a fineness of 200 mesh, heat to 80℃, stir and react for 40min;

[0065] Step 2: Cool to 55°C, inject 1992.8g of molten phenol, and stir for 15 minutes; inject 2595.6g of 37% formaldehyde solution, react at 55°C for 30 minutes, heat to 85°C, and continue the reaction for 60 minutes;

[0066] Step 3: Add 300g of PEG400, cool to 70°C under stirring, and vacuum dehydrate for 60 minutes; cool to below 35°C, discharge the material, and prepare a biomass-modified foamable phenolic resin;

[0067] Step 4: Prefabricate a frame mold with a length of 500 mm, a width of 400 mm, and a height of 50 mm, place the mold on a stainless steel pad, lay a layer of non-woven fabric on the bottom of the mold, and apply a release agent to the inner wall of the mold; weigh 700 g of the biomass-modified foamable phenolic resin prepared in step 3, pour it into a rapidly stirred container, adjust the pH value to 5.0 with a mixed acid prepared by mixing p-toluenesulfonic acid and phosphoric acid in a mass ratio of 1: 1, and add 35 g of a surfactant (Tween-80 and OP-10 are mixed in a mass ratio of 1: 1) in sequence, 28 g of a curing accelerator zinc chloride, and 70 g of a n-pentane foaming agent in proportion, and stir rapidly;

[0068] Step 5: Pour the evenly stirred material into the mold, lay it evenly, cover it with a layer of non-woven fabric, and cover the mold with a stainless steel pressing plate covered with exhaust holes; then send the whole into a preheated drying oven, foam it at 75°C for 40 minutes, take it out and cool it to make a building insulation sandwich foam material.

[0069] The sources of the products used in the above examples and comparative examples are shown in Table 1 below:

[0070] Table 1 Sources of products used in Examples and Comparative Examples

[0071]

[0072] The foam materials prepared in the above embodiments and comparative examples were subjected to performance tests in accordance with relevant provisions of standards such as GB / T17657 "Test methods for physical and chemical properties of wood-based panels and veneered wood-based panels", GB / T8813 "Determination of compression properties of rigid foam plastics", GB / T8811 "Test method for dimensional stability of rigid foam plastics", GB / T18696.1 "Measurement of sound absorption coefficient and acoustic impedance in acoustic impedance tubes", GB / T2406.3 "Plastic oxygen index method for determination of combustion behavior - Part 3", and GB / T10294 "Determination of thermal resistance and related properties of insulating materials". The phase change enthalpy was tested using a differential scanning calorimeter. The relevant test data are shown in Table 2 below.

[0073] Table 2 Performance test data of foam materials prepared in different embodiments and comparative examples

[0074]

[0075]

[0076] The test data in Table 2 above show that, with similar foam density, the embodiment of the present invention has significantly higher strength than the comparative example, better sound absorption performance in all frequency bands, significantly improved dimensional stability and pulverization and slagging defects, similar thermal conductivity to that of the comparative example, and flame retardancy exceeding the flame retardant level. The addition of phase change microcapsules imparts a certain heat storage and release capacity to the foam material.

[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a building thermal insulation sandwich foam material, characterized in that: The following steps are involved: S1: Pour purified water and caustic soda into a reactor with stirring, add biomass powder, heat to 70-90°C, stir and react for 20-40 minutes, and then cool to 45-60°C; the biomass powder is one or more of corn cob powder, coconut shell powder, grapefruit peel powder, and oil tea peel powder, and the biomass powder has a fineness of 180 mesh or above; the mass ratio of purified water, caustic soda, and biomass powder is 100:(20-40):(5-20); S2: injecting molten phenol and formaldehyde solution into the reactor, reacting at 50-60°C for 30-40 minutes, then heating to 80-95°C and continuing the reaction for 60-90 minutes; the concentration of the formaldehyde solution is 37-37.5%; in S1-S2, the molar ratio of phenol, formaldehyde, and caustic soda is 1:(1.47-2.12):(0.15-0.4); S3: adding PEG 400 to the reactor, stirring, cooling to 70-75° C., vacuum dehydration, cooling to 0-35° C., discharging, and preparing a biomass-modified foamable phenolic resin; the vacuum dehydration time is 40-90 min; in S2-S3, the mass ratio of phenol to PEG 400 is 100:(5-30); S4: injecting the above-mentioned biomass-modified foamable phenolic resin into a container, adjusting the pH to 3.5-5.5 with acid, and sequentially adding a surfactant, a curing accelerator, a foaming agent, and a phase change microcapsule, and stirring; the surfactant is a mixture of Tween-80 and OP-10, the mass ratio of the two is 1:1, and the amount used is 3%-8% of the mass of the foamable resin; the curing accelerator is one or both of zinc chloride and calcium chloride, and the amount used is 2%-5% of the mass of the foamable resin; the acid is p-toluenesulfonic acid and phosphoric acid, and the mass ratio of p-toluenesulfonic acid and phosphoric acid is 100:(50-100); the foaming agent is n-pentane, and the amount used is 5%-15% of the mass of the foamable resin; the phase change material of the phase change microcapsule is n-octadecane, and the wall material is one or more of melamine resin, methyl methacrylate or acrylic resin, and the amount used is 2%-10% of the mass of the foamable resin; S5: injecting the material obtained in S4 into a mold with a non-woven fabric on the bottom, covering the non-woven fabric on the top and putting it into a hot press, foaming it, taking it out and cooling it to make a building insulation sandwich foam material; the foaming temperature is 70-95°C, and the foaming time is 30-50min.

2. A building insulation sandwich foam material, characterized in that: The preparation method according to claim 1 is used for preparation.

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