Polyether polyol for polyurethane wood-like material and preparation method thereof

Abstract

The present invention relates to the technical field of polyether polyol production for polyurethane wood-like materials, specifically polyether polyol for polyurethane wood-like materials and a preparation method thereof. The method comprises the following steps: putting a fluorine-containing compound into a reactor according to a mass ratio, adding an alkaline catalyst at the same time, and dripping ethylene oxide after heating; then adding trimethylolpropane to the reactor, adding an alkaline catalyst, and obtaining a polymer intermediate; continuing to heat and stir, and when the temperature rises to 105-115°C, dripping propylene oxide, and after the dripping is completed, performing an internal pressure reaction; after the internal pressure reaction is completed, cooling and nitrogen bubbling are performed to obtain polyether polyol for polyurethane wood-like materials; the synthesized product of the present invention is polyether polyol for polyurethane wood-like materials, which has a lower viscosity and hydroxyl value, has good mutual solubility with water, has good compatibility with conventional polyether products, and is more stable in a full-water wood-like combined polyether system.

Description

Technical Field

[0001] The invention relates to the technical field of polyether polyol production, in particular to polyether polyol for polyurethane wood-like material and a preparation method thereof. Background Art

[0002] Polyurethane imitation wood material or polyurethane synthetic wood, from the perspective of polyurethane materials, is a kind of medium-to-high density structural rigid polyurethane foam plastic (referred to as polyurethane rigid foam). It has a micro-cell structure and has a much higher density than conventional rigid polyurethane foam plastic for thermal insulation, and the density is usually higher than 0.2g / cm 3 (200kg / m 3 ), the density of special wood-like materials can also be lower than this value: most polyurethane structural foam plastics used for synthetic wood have dense and tough skins, and belong to integral skin (or self-skinning) rigid foam plastics. Polyurethane imitation wood materials belong to polyurethane structural rigid foams, which are made by combining polyether and isocyanate and reacting. They are generally produced by molding process, and some are produced by reaction molding (RIM) or reaction injection molding (RRIM) process. The fluidity of the material is more important. Generally speaking, the lower the viscosity of the material, the better the fluidity and the easier it is to fill the mold. The viscosity of the isocyanate component is generally below 500mPa·s: the viscosity of the combined polyether component is generally less than 1000mPa·s, preferably less than 500mPa·s. The viscosity of the two components cannot differ too much, otherwise the ratio of machine foaming will be biased, and the material mixing may not be very uniform.

[0003] In polyurethane rigid foam wood-like composite polyether materials, polyether polyol is one of the main raw materials, which not only affects the viscosity and other parameters of the composite polyether and the foaming process, but also affects the physical properties of the product. Generally, within a certain range, the higher the average functionality of the polyether polyol, the greater the cross-linking degree of the obtained polymer, and the higher the mechanical properties and heat resistance of the product. However, high-functionality polyether polyols have high viscosity, composite polyethers have high viscosity, and the foaming material has poor process performance such as fluidity, which may cause uneven injection molding and defects in parts. Therefore, in the wood-like rigid foam raw material system, generally, some low-viscosity low-functionality polyether polyols (such as polyether diols or polyether triols) are added to high-functionality polyether polyols, and their ratio is adjusted within a certain range, with high-functionality polyether polyols as the main ones. The average functionality of polyether polyols can be controlled in the range of 3.5-4, so that the combined polyether has good fluidity and the rigid foam products have good performance. However, polyether polyols have high viscosity, are inconvenient to use, and have poor process operability. The process practicality can only be increased by adjusting the density, but often the mechanical properties are reduced while the density is reduced; if the amount of low-functionality polyether is too large, the compression strength of the rigid foam obtained at the same density will be reduced, and the post-curing time of the foam will also increase significantly. How to balance the amount of high-functionality polyether to ensure the density parameters and mechanical properties, and at the same time add low-functionality polyether to ensure the low viscosity, good fluidity and processability of the combined polyether system has always been a difficult point in the formulation.

[0004] In addition, large bubbles should be avoided on the surface and shallow surface of polyurethane rigid foam wood-like products (rough and one-time finished products). Due to factors such as viscosity, fluidity, mold temperature, and process of wood-like composite polyether, bubbles are easily generated during demoulding, and it is quite difficult to fill a large number of small bubbles. How to solve the problem of bubbles in polyurethane rigid foam wood-like products has become an issue that must be considered in the production of polyurethane rigid foam wood-like products. Summary of the invention

[0005] In view of the above deficiencies in the prior art, the purpose of the present invention is to provide a polyether polyol for polyurethane imitation wood materials, which solves the problem of reduced strength and easy generation of bubbles on the surface of polyurethane imitation wood products during the production process.

[0006] Another object of the present invention is to provide a method for preparing polyether polyol for polyurethane wood-like material, using fluorine-containing compounds as initiators, pre-dripping ethylene oxide at low temperature and then mixing trimethylolpropane for degassing, then heating and continuously adding propylene oxide to synthesize polyether polyol for polyurethane wood-like material.

[0007] The present invention is achieved by adopting the following technical solutions:

[0008] The method for preparing the polyether polyol for the polyurethane wood-like material comprises the following steps:

[0009] (1) Add the fluorine-containing compound into the reaction kettle according to the mass ratio, and add the alkaline catalyst at the same time. After the kettle is closed for leak testing and replacement, the temperature is raised to 60-70°C under nitrogen atmosphere, the alkylene oxide valve is opened, and ethylene oxide is added dropwise. After the feeding is completed, the internal pressure is adjusted to below -0.05 MPa to obtain the fluorine-containing compound feed;

[0010] (2) Based on the fluorine-containing compound raw material obtained in step (1), trimethylolpropane and a basic catalyst are added to the reaction kettle, and after stirring and heating, vacuum bubbling and degassing are started to obtain a polymer intermediate;

[0011] (3) The polymer intermediate obtained in step (2) is heated and stirred continuously. When the temperature reaches 105-115°C, the valve of the alkylene oxide compound is opened and propylene oxide is added dropwise. After the addition is completed, an internal pressure reaction is carried out;

[0012] (4) After the internal pressure reaction is completed, the temperature is lowered and nitrogen bubbling is performed to remove residual small molecular substances in the product, and the temperature is lowered and the product is discharged to obtain polyether polyol for polyurethane imitation wood material;

[0013] The mass percentages of the fluorine-containing compound, ethylene oxide, trimethylolpropane and propylene oxide are: (6-12.4): (48.01-59.41): (8.6-18.2): (20.58-25.46).

[0014] The fluorine-containing compound is a fluorine-containing aniline compound containing a benzene ring fluorine element, and the fluorine content is 29.8-42.46%.

[0015] The alkaline catalyst in step (1) and step (2) is one of C12-C14 tertiary amine and triethylamine. The amount of the alkaline catalyst added in step (1) is 0.3-0.8‰ of the total mass of all raw materials, preferably 0.5‰; the amount of the alkaline catalyst added in step (2) is 2-5‰ of the total mass of all raw materials, preferably 2.5‰.

[0016] In the step (2), the temperature is raised to 105-115° C. with stirring, and the vacuum bubbling degassing time is 1.5-2.0 h.

[0017] In the step (3), during the dropwise addition of propylene oxide, the pressure is 0.25-0.35 MPa and the temperature is controlled at 105-125° C. After the dropwise addition is completed, the reaction is continued at an internal pressure within the range of 0.2-0.4 MPa for 2-3 hours.

[0018] In the step (4), when the temperature is lowered for nitrogen bubbling, the temperature is lowered to 90-100° C. and the bubbling time is 1-2 hours.

[0019] In the step (4), the fluorine content of the polyether polyol used in the polyurethane wood-like material is 1.78-5.26%.

[0020] The alkylene oxide compounds are ethylene oxide and propylene oxide, and the ethylene oxide is polymerized first and then the propylene oxide.

[0021] The polyether polyol for polyurethane imitation wood material is prepared by the preparation method of the polyether polyol for polyurethane imitation wood material.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The synthesized product of the present invention is a polyether polyol for polyurethane wood-like materials, which has a lower viscosity and hydroxyl value, good miscibility with water, good compatibility with conventional polyether products, and is more stable in the all-water wood-like composite polyether system.

[0024] (2) The fluorine-containing raw material used in the present invention has a high fluorine content, which can significantly improve the surface condition of the wood-like material and reduce defects such as pinholes and bubbles.

[0025] (3) The fluorine-containing compound selected in the present invention contains a benzene ring and is compounded with trimethylolpropane, which can provide better strength and demoulding properties in the wood-like composite polyether system. DETAILED DESCRIPTION

[0026] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0027] Polyether R4110 Shandong Yinuowei New Materials Co., Ltd.;

[0028] Polyether R6205 Shandong Yinuowei New Materials Co., Ltd.;

[0029] Foaming agent L6100 Momentive High-Tech Materials Group;

[0030] Catalyst PC8 Nanjing Meside New Materials Co., Ltd.;

[0031] TCEP Shandong Yarong Chemical Co., Ltd.;

[0032] Polyphenylpolymethylene polyisocyanate Wanhua Chemical Group Co., Ltd.

[0033] Example 1

[0034] (1) 80 g of 3-(trifluoromethoxy)benzylamine with a fluorine content of 29.8% was added into a 2.5 L reactor, and 0.6 g of alkaline catalyst triethylamine was added at the same time. After the reactor was closed for leak testing and replacement, the temperature was raised to 65° C. under a nitrogen atmosphere, and the valve of the alkylene oxide compound was opened to dropwise add 777.8 g of ethylene oxide. After the feeding was completed, the internal pressure was adjusted to -0.05 MPa to obtain a fluorine-containing compound feed;

[0035] (2) Based on the fluorine-containing compound obtained in step (1), 120 g of trimethylolpropane and 3.2 g of alkaline catalyst triethylamine were added to the reaction kettle, and the mixture was heated to 105° C. and then vacuum degassing was started. The vacuum bubbling degassing was performed for 1.5 h to obtain a polymer intermediate.

[0036] (3) The polymer intermediate obtained in step (2) was heated and stirred continuously. When the temperature reached 110°C, the valve of the alkylene oxide compound was opened and 333.2 g of propylene oxide was added dropwise to carry out polymerization reaction. During the addition, the pressure was kept at 0.35 MPa and the temperature was controlled at 115°C. After the addition was completed, the reaction was continued at an internal pressure of 0.25 MPa for 2.5 h.

[0037] (4) After the internal pressure reaction was completed, the temperature was lowered to 90°C and nitrogen was bubbled to remove residual small molecular substances in the product. After bubbling for 1 hour, the temperature was lowered and the product was discharged to obtain polyether polyol A with a fluorine content of 1.78%, a hydroxyl value of 151.4 mgKOH / g, and a viscosity of 143 mPa·s.

[0038] Example 2

[0039] (1) 84 g of 3-aminotrifluorotoluene with a fluorine content of 35.4% was added into a 2.5 L reactor, and 0.7 g of alkaline catalyst tetradecyl dimethyl tertiary amine was added at the same time. After the reactor was closed for leak testing and replacement, the temperature was raised to 60° C. under a nitrogen atmosphere, and the valve of the alkylene oxide compound was opened to dropwise add 336.7 g of ethylene oxide. After the feeding was completed, the internal pressure dropped to -0.05 MPa to obtain a fluorine-containing compound feedstock;

[0040] (2) Based on the fluorine-containing compound obtained in step (1), 120 g of trimethylolpropane and 3.7 g of alkaline catalyst dodecadecyl dimethyl tertiary amine were added to the reaction kettle, and the mixture was heated to 110° C. with stirring and then vacuum degassing was started. The vacuum bubbling degassing was performed for 2 h to obtain a polymer intermediate.

[0041] (3) The polymer intermediate obtained in step (2) was heated and stirred continuously. When the temperature reached 105°C, the valve of the alkylene oxide compound was opened and 144.3 g of propylene oxide was added dropwise to carry out polymerization reaction. During the addition, the pressure was kept at 0.3 MPa and the temperature was controlled at 105°C. After the addition was completed, the reaction was continued at an internal pressure of 0.2 MPa for 2 h.

[0042] (4) After the internal pressure reaction was completed, the temperature was lowered to 95°C and nitrogen was bubbled to remove residual small molecular substances in the product. After bubbling for 1.5 hours, the temperature was lowered and the product was discharged to obtain polyether polyol B with a fluorine content of 4.3%, a hydroxyl value of 302.2 mgKOH / g, and a viscosity of 344 mPa·s.

[0043] Example 3

[0044] (1) 81 g of 2-fluoro-5-trifluoromethylaniline with a fluorine content of 42.4% was added into a 2.5 L reaction kettle, and 0.67 g of alkaline catalyst triethylamine was added at the same time. After the kettle was closed for leak testing and replacement, the temperature was raised to 70° C. under a nitrogen atmosphere, and the valve of the alkylene oxide compound was opened to dropwise add 326.9 g of ethylene oxide. After the feeding was completed, the internal pressure dropped to -0.05 MPa to obtain a fluorine-containing compound feedstock;

[0045] (2) Based on the fluorine-containing compound obtained in step (1), 120 g of trimethylolpropane and 3.7 g of alkaline catalyst triethylamine were added to the reaction kettle, and the mixture was heated to 115° C. and then vacuum degassing was started. The vacuum bubbling degassing was performed for 2 h to obtain a polymer intermediate.

[0046] (3) The polymer intermediate obtained in step (2) was heated and stirred continuously. When the temperature reached 115°C, the valve of the alkylene oxide compound was opened and 140.1 g of propylene oxide was added dropwise to carry out polymerization reaction. During the addition, the pressure was kept at 0.25 MPa and the temperature was controlled at 125°C. After the addition was completed, the reaction was continued at an internal pressure of 0.4 MPa for 3 h.

[0047] (4) After the internal pressure reaction was completed, the temperature was lowered to 100°C and nitrogen was bubbled to remove residual small molecular substances in the product. After bubbling for 2 hours, the temperature was lowered and the product was discharged to obtain polyether polyol C with a fluorine content of 5.1%, a hydroxyl value of 301.8 mgKOH / g, and a viscosity of 287 mPa·s.

[0048] Comparative Example 1

[0049] 286 g of sorbitol liquid, 30 g of sucrose and 30 g of alkaline catalyst dodecadecyl dimethyl tertiary amine were added to the reactor, and 511 g of propylene oxide was slowly added dropwise to the reactor at 80° C. through a pressure vessel. After the addition was completed, the internal pressure was maintained at 110° C. for 2 hours, and then the temperature was raised to 110° C. for dehydration and bubbling for 1.5 hours. After the dehydration was completed, 1785 g of propylene oxide was continued to be added dropwise at 110° C. for polymerization reaction. After the reaction was completed, the internal pressure was maintained at 2 hours for discharge to obtain polyether polyol D with a light yellow transparent liquid appearance, a hydroxyl value of 160 mgKOH / g and a viscosity of 1300 mPa·s.

[0050] Comparative Example 2

[0051] 120g of trimethylolpropane was put into a 2.5L reactor, and 3.7g of alkaline catalyst triethylamine was added. After the reactor was closed for leak testing and replacement, the temperature was raised to 105°C under nitrogen atmosphere and vacuum degassing was started. The vacuum bubbling degassing was carried out for 1.5h; after degassing, the temperature was continued to rise and stir. When the temperature rose to 105°C, the valve of the alkylene oxide compound was opened, and 271g of propylene oxide was added dropwise for polymerization reaction. During the dropwise addition, the pressure was under 0.35MPa and the temperature was controlled at 110°C. After the dropwise addition was completed, the internal pressure reaction was continued within the range of 0.3MPa for 2h; after the internal pressure reaction was completed, the temperature was lowered to about 100°C for nitrogen bubbling to remove the residual small molecular substances in the product. After bubbling for 2h, the temperature was lowered and the material was discharged to obtain polyether polyol E with a hydroxyl value of 385mgKOH / g and a viscosity of 722mPa·s.

[0052] The product indicators of each embodiment and comparative example are shown in Table 1.

[0053] The performance comparison results of each embodiment and comparative example are shown in Table 2.

[0054] Table 1 Product indicators of various examples and comparative examples

[0055]

[0056] Table 2 Performance comparison results of each embodiment and comparative example

[0057]

[0058] In Table 2, the raw materials in the table are mixed and stirred evenly to form component A, which is mixed with component B polyphenyl polymethylene polyisocyanate at a mass ratio of 1:1.2 at 25±2°C, stirred at 4000r / min for 6s, poured into a mold, and opened the mold after 10 minutes to take out the foam for testing.

[0059] From the data in the above table, it can be seen that in terms of fluidity, the addition of Examples 1-3 can significantly improve the foam fluidity. Compared with conventional products, the fluidity increases with the increase of fluorine content, and the pinhole bubbles on the surface also become smaller. The foam performance is not much different from that of the conventional system. At the same time, with the increase of hydroxyl value and fluorine content, the strength does not decrease.

Claims

1. A method for preparing polyether polyol for polyurethane wood-like material, It is characterized in that The following steps are involved: (1) Add the fluorine-containing compound into the reaction kettle according to the mass ratio, and add the alkaline catalyst at the same time. After the kettle is closed for leak testing and replacement, the temperature is raised to 60-70°C under nitrogen atmosphere, the alkylene oxide valve is opened, and ethylene oxide is added dropwise. After the feeding is completed, the internal pressure is adjusted to below -0.05 MPa to obtain the fluorine-containing compound feed; (2) Based on the fluorine-containing compound raw material obtained in step (1), trimethylolpropane and a basic catalyst are added to the reaction kettle, and after stirring and heating, vacuum bubbling and degassing are started to obtain a polymer intermediate; (3) The polymer intermediate obtained in step (2) is heated and stirred continuously. When the temperature reaches 105-115°C, the valve of the alkylene oxide compound is opened and propylene oxide is added dropwise. After the addition is completed, an internal pressure reaction is carried out; (4) After the internal pressure reaction is completed, the temperature is lowered and nitrogen bubbling is performed to remove residual small molecular substances in the product, and the temperature is lowered and the product is discharged to obtain polyether polyol for polyurethane imitation wood material; The mass percentages of the fluorine-containing compound, ethylene oxide, trimethylolpropane and propylene oxide are: (6-12.4): (48.01-59.41): (8.6-18.2): (20.58-25.46); The fluorine-containing compound is one of 3-(trifluoromethoxy)benzylamine, 3-aminotrifluorotoluene and 2-fluoro-5-trifluoromethylaniline.

2. The method for preparing polyether polyol for polyurethane wood-like material according to claim 1, It is characterized in that The alkaline catalyst in step (1) and step (2) is one of C12-C14 tertiary amine and triethylamine. The amount of the alkaline catalyst added in step (1) is 0.3-0.8‰ of the total mass of all raw materials, and the amount of the alkaline catalyst added in step (2) is 2-5‰ of the total mass of all raw materials.

3. The method for preparing polyether polyol for polyurethane wood-like material according to claim 1, It is characterized in that In the step (2), the temperature is raised to 105-115° C. with stirring, and the vacuum bubbling degassing time is 1.5-2.0 h.

4. The method for preparing polyether polyol for polyurethane wood-like material according to claim 1, It is characterized in that In the step (3), during the dropwise addition of propylene oxide, the pressure is 0.25-0.35 MPa and the temperature is controlled at 105-125° C. After the dropwise addition is completed, the reaction is continued at an internal pressure within the range of 0.2-0.4 MPa for 2-3 hours.

5. The method for preparing polyether polyol for polyurethane wood-like material according to claim 1, It is characterized in that In the step (4), when the temperature is lowered for nitrogen bubbling, the temperature is lowered to 90-100° C. and the bubbling time is 1-2 hours.

6. The method for preparing polyether polyol for polyurethane wood-like material according to claim 1, It is characterized in that In the step (4), the fluorine content of the polyether polyol used in the polyurethane wood-like material is 1.78-5.26%.

7. A polyether polyol for polyurethane wood-like material, It is characterized in that The polyurethane wood-like material is prepared by the preparation method of polyether polyol for polyurethane wood-like material according to any one of claims 1 to 6.

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