A polyurethane composite board with high curvature and its preparation method

Abstract

The present invention relates to the technical field of polyurethane composite panels, and specifically relates to a polyurethane composite panel with a high degree of curvature and a preparation method thereof, comprising the following steps: (1) Foaming and mixing each raw material of the polyurethane slurry to obtain a first polyurethane slurry with a foaming expansion rate of 1.1 - 1.3; (2) Foaming and mixing each raw material of the polyurethane slurry to obtain a second polyurethane slurry with a foaming expansion rate of 1.5 - 1.8; (3) Laying a carbon fiber mesh cloth in a mold, and then sequentially pouring the first polyurethane slurry and the second polyurethane slurry along the length direction or the width direction. After circulating the pouring more than 3 times, the first polyurethane slurry is poured again; (4) Then, curing and drying are carried out. The polyurethane composite panel with a specific foaming structure of the present invention can have excellent curvature, and other properties meet the requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane composite panels, and particularly relates to a polyurethane composite panel with high bending degree and a preparation method thereof. Background Art

[0002] Due to its excellent physical properties (such as rubber elasticity, cold resistance and durability), polyurethane resin has recently been used as a sealing material for buildings, automobiles, etc. The sealing materials for buildings and automobiles are required to be applied to base surfaces of various shapes. With the development of the automotive industry, the requirements for the lightweight and strength of automotive interiors are getting higher and higher. In the prior art, polyurethane composite panels are used in automotive roofs. When the automotive roof is applied to the corresponding part of the automotive handle, the rigidity of the automotive roof is insufficient and it is easy to tear. Generally, the rigidity index of the polyurethane panel used for the automotive roof is characterized by the flexural strength.

[0003] Chinese Patent 201721148529.3 discloses a locally high-strength polyurethane composite panel, which comprises eight layers of materials. The polyurethane composite panel, from top to bottom, is successively: a polymer film 1, a first glass fiber layer 2, a first rubber powder layer 3, a polyurethane panel 4, a local area glass fiber layer 5, a second rubber powder layer 6, a second glass fiber layer 7 and a non-woven fabric layer 8; the local area glass fiber layer 5 is composed of a polymer film 9 and a glass fiber layer 10, with a thickness of 200μm - 800μm. Among them, the glass fiber layer 8 is selected from glass fiber cloth, glass fiber felt or glass fiber, and the grammage of the polyurethane composite panel is 800g / m2. In the prior art, there are disadvantages that the cutting of the polyurethane composite panel is inconvenient and easy to break when the local area glass fiber layer is compounded.

[0004] However, in the prior art, there is an urgent need for a polyurethane composite panel with high bending degree. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defect that the bending degree of the existing polyurethane composite panel is low and needs to be improved, and to provide a polyurethane composite panel with high bending degree and a preparation method thereof. The preparation method can prepare a polyurethane composite panel with a specific foaming structure, which has excellent bending degree and other properties meet the requirements.

[0006] To achieve the above purpose, the first aspect of the present invention provides a preparation method of a polyurethane composite panel with high bending degree, comprising the following steps:

[0007] (1) Foaming and mixing each raw material of the polyurethane slurry to obtain a first polyurethane slurry with a foaming expansion ratio of 1.1 - 1.3;

[0008] (2) Foaming and mixing each raw material of the polyurethane slurry to obtain a second polyurethane slurry with a foaming expansion ratio of 1.5 - 1.8;

[0009] (3) Lay the carbon fiber mesh in the mold, and then pour the first polyurethane slurry and the second polyurethane slurry in sequence along the length direction or the width direction. After circulating the pouring for more than 3 times, pour the first polyurethane slurry again;

[0010] (4) Then carry out curing and drying.

[0011] Preferably, in step (1), the raw materials of the polyurethane slurry include polyether polyol, soybean oil polyol, phenyl alkyl sulfonate, diisocyanate, coupling agent, foaming agent, and catalyst.

[0012] More preferably, in step (1), the raw materials of the polyurethane slurry further include foam stabilizer, antioxidant, and preferably filler.

[0013] Preferably, the foaming expansion ratio of the first polyurethane slurry is 1.2 - 1.3, and the foaming expansion ratio of the second polyurethane slurry is 1.5 - 1.6.

[0014] Preferably, in step (3), in the thickness direction, lay one layer of the carbon fiber mesh every 2 - 3 cm thick.

[0015] Preferably, in step (3), the ratio of the pouring width of the first polyurethane slurry to the pouring width of the second polyurethane slurry is 1:0.3 - 0.7.

[0016] More preferably, in step (3), the ratio of the pouring width of the first polyurethane slurry to the pouring width of the second polyurethane slurry is 1:0.3 - 0.5.

[0017] The second aspect of the present invention provides a polyurethane composite board with high curvature prepared by the preparation method described in the first aspect. Carbon fiber meshes are arranged at intervals in the thickness direction inside the polyurethane composite board, and first foaming structures and second foaming structures are arranged at intervals along the length or width direction. The porosity of the first foaming structure is less than the porosity of the second foaming structure.

[0018] Preferably, the porosity of the second foaming structure / the porosity of the first foaming structure is 1.3 - 1.4:1.

[0019] Preferably, in the thickness direction of the polyurethane composite board, lay one layer of the carbon fiber mesh every 2 - 3 cm thick.

[0020] Compared with the prior art, the preparation method of the polyurethane composite board provided by the present invention uses a carbon fiber mesh cloth as a connecting skeleton, which is high-temperature resistant, friction resistant, corrosion resistant, anisotropic, and has good flexibility. By sequentially pouring polyurethane slurries with different specific foaming expansion ratios, a polyurethane composite board with a regular distribution of "foaming porosity in the pattern of small, large, small, large, small, large, small" can be formed. The polyurethane composite board with this specific foaming structure can have excellent bending properties, and other properties meet the requirements. Among them, the carbon fiber mesh cloth, as a connecting skeleton, tightly connects the structures with different foaming expansion ratios into an organic whole. When facing bending, the foaming structures with different foaming expansion ratios interact with each other to slowly release and decompose the bending force received, and the foaming structure itself has a certain flexibility, thus significantly synergistically improving the bending degree of the polyurethane composite board. Detailed Embodiments

[0021] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0022] The first aspect of the present invention provides a method for preparing a polyurethane composite board with high bending degree, comprising the following steps:

[0023] (1) Foam and mix the raw materials of the polyurethane slurry to obtain a first polyurethane slurry with a foaming expansion ratio of 1.1 - 1.3;

[0024] (2) Foam and mix the raw materials of the polyurethane slurry to obtain a second polyurethane slurry with a foaming expansion ratio of 1.5 - 1.8;

[0025] (3) Lay the carbon fiber mesh cloth in the mold, and then sequentially pour the first polyurethane slurry and the second polyurethane slurry along the length direction or the width direction. After circulating the pouring more than 3 times, pour the first polyurethane slurry again;

[0026] (4) Then carry out curing and drying.

[0027] The raw materials of the polyurethane slurry of the present invention can adopt the existing raw material system of polyurethane in the art, as long as the foaming is at the required expansion ratio and a polyurethane composite board can be formed. Preferably, in step (1), the raw materials of the polyurethane slurry include polyether polyol, soybean oil polyol, phenyl alkyl sulfonate, diisocyanate, coupling agent, foaming agent, and catalyst.

[0028] The foaming agent can be sodium dodecyl sulfate.

[0029] More preferably, in step (1), the raw materials of the polyurethane slurry further include a foam stabilizer, an antioxidant, and a filler. The filler is, for example, 40 g of alumina.

[0030] In some specific embodiments, the amounts of the raw materials are as follows: 0.8 - 1.1 kg of polyether polyol, 100 - 120 g of soybean oil polyol, 30 - 40 g of phenyl alkyl sulfonate, 10 - 20 g of antioxidant, 1.2 - 2.0 kg of diisocyanate, 19 - 22 g of vinyltriethoxysilane, 55 - 58 g of polyethylene oxide, and 100 - 110 g of catalyst.

[0031] Preferably, the foaming expansion ratio of the first polyurethane slurry is 1.2 - 1.3, and the foaming expansion ratio of the second polyurethane slurry is 1.5 - 1.6.

[0032] Preferably, in step (3), in the thickness direction, a layer of the carbon fiber mesh is laid every 2 - 3 cm thick. Under this preferred scheme, it is more beneficial to enhance the integrity of different foaming structures of the polyurethane composite board and more beneficial to improve the bending degree of the overall structure.

[0033] Preferably, in step (3), the ratio of the pouring width of the first polyurethane slurry to the second polyurethane slurry is 1:0.3 - 0.7.

[0034] More preferably, in step (3), the ratio of the pouring width of the first polyurethane slurry to the second polyurethane slurry is 1:0.3 - 0.5.

[0035] Under the above preferred scheme, the width of the second polyurethane slurry with a larger foaming expansion rate is appropriate, which can ensure that the surface hardness and other strengths of the polyurethane composite board are at a relatively high level, and is more beneficial to improving the comprehensive performance of the polyurethane composite board. If the width of the second polyurethane slurry with a larger foaming expansion rate is too large, it will affect the surface hardness of the polyurethane composite board; if it is too small, the bending degree of the polyurethane composite board cannot reach the optimum.

[0036] In step (4) of the present invention, the conditions of curing and drying can be carried out according to the existing methods, and the present invention does not particularly limit this.

[0037] The second aspect of the present invention provides a polyurethane composite board with a high bending degree prepared by the preparation method described in the first aspect. Carbon fiber meshes are arranged at intervals in the thickness direction inside the polyurethane composite board, and first foaming structures and second foaming structures are arranged at intervals in the length or width direction. The porosity of the first foaming structure is less than that of the second foaming structure.

[0038] Preferably, the porosity of the second foaming structure / the porosity of the first foaming structure is 1.3 - 1.4:1. Under this preferred scheme, it is more conducive to improving the comprehensive properties such as the surface hardness and bending degree of the polyurethane composite board.

[0039] Preferably, in the thickness direction of the polyurethane composite board, one layer of the carbon fiber mesh is provided every 2 - 3 cm in thickness.

[0040] The following will describe the present invention in detail through examples. The preparation method of the catalyst is to dissolve 6 g of dibutyltin dilaurate in 50 g of ethyl acetate, then immerse 30 g of calcium oxide with a mesh size of 200 in the ethyl acetate solution, evacuate to -0.1 Mpa and heat to 80 °C to remove the solvent ethyl acetate, obtaining calcium oxide particles coated with dibutyltin dilaurate.

[0041] Example 1

[0042] A polyurethane composite board with a high bending degree, in which carbon fiber meshes are arranged at intervals in the thickness direction, and first foaming structures and second foaming structures are arranged at intervals in the length or width direction, and the porosity of the second foaming structure / the porosity of the first foaming structure is 1.3:1.

[0043] Its preparation method includes the following steps:

[0044] (1) Foam and mix the raw materials of the polyurethane slurry to obtain a first polyurethane slurry with a foaming expansion ratio of 1.2;

[0045] (2) Foam and mix the raw materials of the polyurethane slurry to obtain a second polyurethane slurry with a foaming expansion ratio of 1.56;

[0046] Among them, the dosage of each raw material is: 1 kg of polyether polyol (molecular weight 800, hydroxyl value 200 mgKOH / g), 110 g of soybean oil polyol (hydroxyl value 140 mgKOH / g), 30 g of phenyl alkyl sulfonate, 10 g of antioxidant 1,3,5 - trimethyl - 2,4,6 - tris(3,5 - di - tert - butyl - 4 - hydroxybenzyl)benzene, 1.5 kg of diphenylmethane diisocyanate, 20 g of vinyltriethoxysilane, 55 g of polyethylene oxide, 100 g of catalyst. The amount of the foaming agent sodium dodecyl sulfate is determined according to the required foaming expansion ratio.

[0047] (3) Lay the carbon fiber mesh in the mold, then pour the first polyurethane slurry and the second polyurethane slurry in sequence along the width direction, and pour in this cycle more than 3 times until the required width, and then pour the first polyurethane slurry again; in the thickness direction, one layer of the carbon fiber mesh is laid every 3 cm in thickness. The ratio of the pouring width of the first polyurethane slurry to the second polyurethane slurry is 1:0.4.

[0048] (4) Then carry out curing and drying.

[0049] Example 2

[0050] It is carried out according to the method of Example 1, except that the foaming expansion ratio of the first polyurethane slurry is 1.1.

[0051] Example 3

[0052] It is carried out according to the method of Example 1, except that the foaming expansion ratio of the second polyurethane slurry is 1.8.

[0053] Example 4

[0054] It is carried out according to the method of Example 1, except that the ratio of the pouring width of the first polyurethane slurry to that of the second polyurethane slurry is 1:0.1.

[0055] Example 5

[0056] It is carried out according to the method of Example 1, except that the ratio of the pouring width of the first polyurethane slurry to that of the second polyurethane slurry is 1:0.7.

[0057] Comparative Example 1

[0058] It is carried out according to the method of Example 1, except that the carbon fiber mesh is not laid.

[0059] Comparative Example 2

[0060] It is carried out according to the method of Example 1, except that the foaming expansion ratio of the second polyurethane slurry is 2.5.

[0061] Comparative Example 3

[0062] It is carried out according to the method of Example 1, except that the foaming expansion ratio of the first polyurethane slurry is 1.56.

[0063] Test Example

[0064] Carry out the performance tests shown in Table 1 on the polyurethane composite boards of the above examples and comparative examples.

[0065] Table 1

[0066]

[0067] , It can be seen from the results in Table 1 that the examples of the present invention have significantly better effects.

[0068] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A preparation method of a polyurethane composite board with high curvature, characterized in that, it comprises the following steps: (1) Foaming and mixing each raw material of the polyurethane slurry to obtain a first polyurethane slurry with a foaming expansion ratio of 1.1 - 1.3; (2) Foaming and mixing each raw material of the polyurethane slurry to obtain a second polyurethane slurry with a foaming expansion ratio of 1.5 - 1.8; (3) Lay the carbon fiber mesh cloth in the mold, and then pour the first polyurethane slurry and the second polyurethane slurry successively along the length direction or the width direction. After circulating pouring more than 3 times, pour the first polyurethane slurry again; (4) Then carry out curing and drying.

2. The preparation method according to claim 1, characterized in that, in step (1), each raw material of the polyurethane slurry includes polyether polyol, soybean oil polyol, phenyl alkyl sulfonate, diisocyanate, coupling agent, foaming agent, catalyst.

3. The preparation method according to claim 2, characterized in that, in step (1), each raw material of the polyurethane slurry further includes foam stabilizer, antioxidant and filler.

4. The preparation method according to claim 1, characterized in that, the foaming expansion ratio of the first polyurethane slurry is 1.2 - 1.3, and the foaming expansion ratio of the second polyurethane slurry is 1.5 - 1.

6.

5. The preparation method according to claim 1, characterized in that, in step (3), in the thickness direction, lay one layer of the carbon fiber mesh cloth every 2 - 3 cm thick.

6. The preparation method according to claim 1, characterized in that, in step (3), the ratio of the pouring width of the first polyurethane slurry to the pouring width of the second polyurethane slurry is 1:0.3 - 0.

7.

7. The preparation method according to claim 6, characterized in that, in step (3), the ratio of the pouring width of the first polyurethane slurry to the pouring width of the second polyurethane slurry is 1:0.3 - 0.

5.

8. A polyurethane composite board with high curvature prepared by the preparation method according to any one of claims 1 - 7, characterized in that, carbon fiber mesh cloth is arranged at intervals in the thickness direction inside the polyurethane composite board, and first foaming structures and second foaming structures are arranged at intervals in the length or width direction. The porosity of the first foaming structure is less than the porosity of the second foaming structure.

9. The polyurethane composite board according to claim 8, characterized in that, the porosity of the second foaming structure / the porosity of the first foaming structure is 1.3 - 1.4:

1.

10. The polyurethane composite board according to claim 8, characterized in that, in the thickness direction of the polyurethane composite board, lay one layer of the carbon fiber mesh cloth every 2 - 3 cm thick.

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