Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a cold-resistant high static rigidity polyurethane microporous elastic cushion plate, which is characterized in that the raw material components and the content of each component of the polyurethane microporous elastic cushion plate are optimized, and on the premise of ensuring that the polyurethane microporous elastic cushion plate meets the use requirements of other indexes such as static rigidity, dynamic and static rigidity ratio and the like, the pressure in micropores in the polyurethane microporous elastic cushion plate is properly increased, so that the volume shrinkage rate of the polyurethane elastic cushion plate at low temperature is reduced, the static rigidity change rate of the polyurethane elastic cushion plate at minus 35 ℃ for 16h is lower than 20%, and the high static rigidity ((23 +/-2.3) kN/mm and 1 kN-35 kN) loaded polyurethane microporous elastic cushion plate for the urban railway passenger transport line meeting the requirements of each index is obtained.
The purpose of the invention is realized by the following technical scheme.
A cold-resistant high-static-stiffness polyurethane microporous elastic backing plate is obtained by curing and molding a component A and a component B, and the density of the elastic backing plate is 650kg/m3~700kg/m3And loading the polyurethane microporous elastic cushion plate with static rigidity of (23 +/-2.3) kN/mm under 1 kN-35 kN, thereby meeting various index requirements of the elastic cushion plate for the urban railway passenger transport line.
The component A is prepared by uniformly mixing polyether polyol, a chain extender, a foaming agent, a foam stabilizer and a catalyst; the polyether polyol comprises polytetrahydrofuran ether glycol (PTMEG1000) with a molecular weight of 1000, polytetrahydrofuran ether glycol (PTMEG2000) with a molecular weight of 2000 and polyoxypropylene triol (EP330) with a molecular weight of 5000; the chain extender is 1, 4-Butanediol (BDO); the foaming agent is H2O; the foam stabilizer is AK7703 available from Jiangsu Maisrd; the catalyst comprises bis (dimethylaminoethyl) ether (BDMAE) and dibutyltin dilaurate (T12);
taking the total mass of the raw materials for preparing the component A as 100 parts, the raw materials for preparing the component A and the mass contents of the components are as follows:
the component B is a prepolymer with an NCO value of 12-15 formed by stirring and reacting a compound containing-NCO groups and polytetrahydrofuran ether polyol at the temperature of 80-100 ℃ for 4-6 h.
Component A contains active-H (active H and H in polyol-OH)2The sum of active groups in O) and-NCO groups contained in the component B (the-NCO groups remained after the compound containing the-NCO groups reacts with the polytetrahydrofuran ether polyol) are subjected to quantitative reaction, and the molar ratio of the active groups to the-NCO groups is 1.00: (0.98-1.03), preferably 1.00: (0.99 to 1.01).
Further, preheating the component A to 35 +/-2) DEG C and the component B to 45 +/-2℃, uniformly mixing the preheated component A and the preheated component B, pouring the mixture into a mold preheated to 65 +/-5℃, placing the mold at 65 +/-5℃, curing for 10-15 min, and forming the cold-resistant polyurethane microporous elastic cushion plate with high static rigidity in the mold.
Further, the total mass of the raw materials for preparing the component A is 100 parts, so that the raw materials for preparing the component A and the mass contents of the components are as follows:
further, in the preparation of the component B, the compound containing-NCO groups is diphenylmethane diisocyanate (MDI); the polytetrahydrofuran ether polyol is a mixture of PTMEG1000 and PTMEG2000, and accordingly, the mass ratio of the PTMEG1000 to the PTMEG2000 is more preferably 1.3-1.7: 1.
Further, when the compound containing the-NCO group is MDI and the polytetrahydrofuran ether polyol is a mixture of PTMEG1000 and PTMEG2000, the raw material components for preparing the B component and the mass contents of the components are as follows, based on 100 parts by mass of the total raw materials for preparing the B component:
PTMEG 100025-40 parts
PTMEG 200015-25 parts
40-60 parts of MDI.
Has the advantages that:
(1) according to the invention, by selecting the raw material components for preparing the polyurethane microporous elastic base plate and regulating and controlling the content of each component, on the premise of ensuring that the polyurethane microporous elastic base plate meets the use requirements of other indexes such as static stiffness, dynamic-static stiffness ratio and the like, the pressure in micropores in the polyurethane microporous elastic base plate is properly increased, so that the volume change rate of the polyurethane microporous elastic base plate at low temperature is reduced, and the prepared density is 650kg/m3~700kg/m3And the static rigidity change rate of the polyurethane microporous elastic base plate with the static rigidity of ((23 +/-2.3) kN/mm and the loading of 1 kN-35 kN) is less than 20 percent at the temperature of-35 ℃ for 16h, so that the vibration reduction effect of the polyurethane microporous elastic base plate at low temperature is ensured, and various index requirements used by urban railway passenger lines are met.
(2) In the polyurethane microporous elastic backing plate, the glass transition temperature of the polyurethane elastomer matrix is as low as-66 ℃, so that the phenomenon that the rigidity of the elastic backing plate is obviously increased due to the glass transition phenomenon of macromolecules is avoided at-35 ℃, and only the contraction of the polyurethane elastomer matrix and gas in micropores occurs at low temperature.
(3) In the polyurethane microporous elastic base plate, chemical foaming agent H2CO generated in the preparation process of the polyurethane microporous elastic base plate under the influence of O content2Amount of gas by regulating H2The content of O can properly increase the amount of gas in micropores in the polyurethane elastomer matrix on the premise of not increasing the volume occupied by the gas in the prepared polyurethane micropore elastic cushion plate, thereby increasing the pressure of the gas in the micropores. However, H2Too high an amount of O leads to the formation of CO2The amount of gas is increased, the pressure in the micropores is too high, the walls of the micropores are easy to break through in the gel forming process of the polyurethane elastomer, the closed pore rate is reduced, and the low-temperature volume shrinkage rate of the product is increased; in addition, the hardness and rigidity of the product are increased due to the excessive pressure in the micropores, and the product hardness and rigidity exceed the product performance index range.
(4) In the polyurethane microporous elastic base plate, the foam stabilizer plays the key roles of adjusting the closed pore rate of micropores, adjusting the nucleation number of the micropores and adjusting the uniformity of the sizes of the micropores, and the closed pore rate can reach over 90 percent by regulating and controlling the type and the content of the foam stabilizer. The closed cell rate is reduced due to the low content of the foam stabilizer, and the effect of further improving the closed cell rate is not achieved due to the high content of the foam stabilizer, and other performances can be influenced.
(5) In the polyurethane microporous elastic base plate, the BDMAE catalyst is used for catalyzing-NCO and H2Foaming reaction between O, which reaction releases CO2A gas; the T-12 catalyst is used to catalyze the gel reaction between-NCO and-OH, the reaction product being the bulk of the polyurethane elastomer matrix formed. The foaming and gel reaction rates must be matched to prepare the polyurethane microporous elastic backing plate with proper gas pressure in micropores, proper closed porosity and no defect in appearance. If the gel reaction rate is too high, the average molecular weight of the polyurethane elastomer matrix is increased rapidly, the swelling binding force on the micropores is increased, the growth size of the micropores is affected, the occupied volume of the micropores is reduced, the swelling volume is insufficient, the appearance quality of the product is affected, and the density, elasticity and rigidity of the product are increased. If the foaming reaction rate is too fast, CO produced in unit time2The gas is increased, the strength of the polyurethane elastomer matrix is not enough to restrain the volume expansion of the gas in the micropores, so that the walls of the micropores are cracked, and the closed porosity is reduced; in addition, too much gas forms larger bubbles, which affects the uniformity of the size distribution of the micropores and may even cause a cosmetic defect of dimpling on the upper surface of the product.
Detailed Description
The present invention is further illustrated by the following detailed description, wherein the processes are conventional unless otherwise specified, and the starting materials are commercially available from a public source without further specification.
Example 1
(1) 15 parts of PTMEG1000 (polytetrahydrofuran ether glycol with functionality of 2 and molecular weight of 1000), 51 parts of PTMEG2000 (polytetrahydrofuran ether glycol with functionality of 2 and molecular weight of 2000), 24.4 parts of EP330 (polyoxypropylene triol with functionality of 3 and molecular weight of 5000), 8.3 parts of BDO (1, 4-butanediol), 0.2 part of H2O, 0.951 part of AK7703, 0.13 part of BDMAE (bis (dimethylaminoethyl) ether) and 0.019 part of T-12 (dibutyltin dilaurate) are uniformly mixed to obtain a component A;
mixing 50 parts of MDI (diphenylmethane diisocyanate), 30 parts of PTMEG1000 and 20 parts of PTMEG2000, and stirring and reacting for 4 hours at 85 ℃ under the nitrogen protection atmosphere to obtain a component B with an-NCO value of 13.39;
(2) according to the mol ratio of active-H in the component A to-NCO group in the component B of 1:1, the component A preheated to 35 ℃ and the component B preheated to 45 ℃ are uniformly mixed by a two-component polyurethane casting machine and then are cast into a lockable mould (the mould can be locked, the volume in the mould cavity cannot be influenced by material expansion) preheated to 65 ℃, and the volume of the inner cavity is 868cm3The mold is filled with a mixture with the total mass of 607.6g, the mold filled with the mixture is placed at 65 ℃ for curing for 10 minutes, the mold is filled with the mixture after expansion molding, and the cold-resistant polyurethane microporous elastic cushion plate with high static rigidity is molded in the mold.
The microstructure of the elastic base plate prepared in the embodiment is characterized, and as can be seen from the SEM photograph in fig. 1, the distribution range of the sizes of the micropores in the prepared elastic base plate is narrow, and the sizes of the micropores are uniform.
Example 2
(1) 15 parts of PTMEG1000, 51 parts of PTMEG2000, 24.4 parts of EP330, 8.3 parts of BDO and 0.23 part of H2Mixing O, 0.91 part of AK7703, 0.14 part of BDMAE and 0.02 part of T-12 uniformly to obtain a component A;
mixing 50 parts of MDI, 30 parts of PTMEG1000 and 20 parts of PTMEG2000, and stirring and reacting for 4 hours at 85 ℃ under the nitrogen protection atmosphere to obtain a component B with the-NCO value of 13.39;
(2) push buttonUniformly mixing the component A preheated to 35 ℃ and the component B preheated to 45 ℃ by a two-component polyurethane casting machine according to the molar ratio of active-H in the component A to-NCO group in the component B of 1:1, and then casting the mixture into a lockable mold preheated to 65 ℃, wherein the volume of an inner cavity is 868cm3The mold is filled with the mixture with the total mass of 564.2g, the mold filled with the mixture is placed at 65 ℃ for curing for 10 minutes, the mold is filled with the mixture after expansion molding, and the cold-resistant polyurethane microporous elastic cushion plate with high static stiffness is molded in the mold.
Comparative example 1
(1) 15 parts of PTMEG1000, 51 parts of PTMEG2000, 24.5 parts of EP330, 8.3 parts of BDO and 0.17 part of H2Mixing O, 0.89 part of AK7703, 0.12 part of BDMAE and 0.02 part of T-12 uniformly to obtain a component A;
mixing 50 parts of MDI, 30 parts of PTMEG1000 and 20 parts of PTMEG2000, and stirring and reacting for 4 hours at 85 ℃ under the nitrogen protection atmosphere to obtain a component B with the-NCO value of 13.39;
(2) according to the mol ratio of active-H in the component A to-NCO group in the component B of 1:1, the component A preheated to 35 ℃ and the component B preheated to 45 ℃ are uniformly mixed by a two-component polyurethane casting machine, and then are cast into a lockable mold preheated to 65 ℃, wherein the volume of an inner cavity is 868cm3The mold is filled with the mixture with the total mass of 564.2g, the mold filled with the mixture is placed at 65 ℃ for curing for 10 minutes, the mold is filled with the mixture after expansion molding, and the polyurethane microporous elastic cushion plate is molded in the mold.
Comparative example 2
(1) 15 parts of PTMEG1000, 51 parts of PTMEG2000, 24.4 parts of EP330, 8.3 parts of BDO and 0.26 part of H2Mixing O, 0.87 part of AK7703, 0.15 part of BDMAE and 0.02 part of T-12 uniformly to obtain a component A;
mixing 50 parts of MDI, 30 parts of PTMEG1000 and 20 parts of PTMEG2000, and stirring and reacting for 4 hours at 85 ℃ under the nitrogen protection atmosphere to obtain a component B with the-NCO value of 13.39;
(2) according to the mol ratio of active-H in the component A to-NCO group in the component B of 1:1, the component A preheated to 35 ℃ and the component B preheated to 45 ℃ are uniformly mixed by a two-component polyurethane casting machine and then are cast to be preheated toIn a lockable mould with 65 ℃, the volume of an inner cavity is 868cm3The mold is filled with the mixture with the total mass of 564.2g, the mold filled with the mixture is placed at 65 ℃ for curing for 10 minutes, the mold is filled with the mixture after expansion molding, and the polyurethane microporous elastic cushion plate is molded in the mold.
The microstructure of the elastic cushion plate prepared by the comparative example is represented, and as can be seen from the SEM picture in FIG. 2, the size distribution range of the micropores in the prepared elastic cushion plate is wider, the sizes of the micropores are not uniform, and the number of the micropores is obviously more than that of the micropores in the embodiment 1.
Comparative example 3
(1) 15 parts of PTMEG1000, 51 parts of PTMEG2000, 24.7 parts of EP330, 8.3 parts of BDO and 0.23 part of H2Mixing O, 0.61 part of AK7703, 0.14 part of BDMAE and 0.02 part of T-12 uniformly to obtain a component A;
mixing 50 parts of MDI, 30 parts of PTMEG1000 and 20 parts of PTMEG2000, and stirring and reacting for 4 hours at 85 ℃ under the nitrogen protection atmosphere to obtain a component B with the-NCO value of 13.39;
(2) according to the mol ratio of active-H in the component A to-NCO group in the component B of 1:1, the component A preheated to 35 ℃ and the component B preheated to 45 ℃ are uniformly mixed by a two-component polyurethane casting machine, and then are cast into a lockable mold preheated to 65 ℃, wherein the volume of an inner cavity is 868cm3The mold is filled with the mixture with the total mass of 564.2g, the mold filled with the mixture is placed at 65 ℃ for curing for 10 minutes, the mold is filled with the mixture after expansion molding, and the polyurethane microporous elastic cushion plate is molded in the mold.
Comparative example 4
(1) 15 parts of PTMEG1000, 51 parts of PTMEG2000, 24 parts of EP330, 8.3 parts of BDO and 0.23 part of H2Mixing O, 1.31 parts of AK7703, 0.14 parts of BDMAE and 0.02 part of T-12 uniformly to obtain a component A;
mixing 50 parts of MDI, 30 parts of PTMEG1000 and 20 parts of PTMEG2000, and stirring and reacting for 4 hours at 85 ℃ under the nitrogen protection atmosphere to obtain a component B with the-NCO value of 13.39;
(2) preheating the component A to 35 ℃ and preheating the component A to 35 ℃ according to the mol ratio of active-H in the component A to-NCO group in the component B of 1:1The component B at 45 ℃ is uniformly mixed by a two-component polyurethane casting machine and then is cast into a lockable mould preheated to 65 ℃, and the volume of an inner cavity is 868cm3The mold is filled with the mixture with the total mass of 564.2g, the mold filled with the mixture is placed at 65 ℃ for curing for 10 minutes, the mold is filled with the mixture after expansion molding, and the polyurethane microporous elastic cushion plate is molded in the mold.
Comparative example 5
(1) 15 parts of PTMEG1000, 51 parts of PTMEG2000, 24.4 parts of EP330, 8.3 parts of BDO and 0.23 part of H2Mixing O, 0.85 part of AK7703, 0.2 part of BDMAE and 0.02 part of T-12 uniformly to obtain a component A;
mixing 50 parts of MDI, 30 parts of PTMEG1000 and 20 parts of PTMEG2000, and stirring and reacting for 4 hours at 85 ℃ under the nitrogen protection atmosphere to obtain a component B with the-NCO value of 13.39;
(2) according to the mol ratio of active-H in the component A to-NCO group in the component B of 1:1, the component A preheated to 35 ℃ and the component B preheated to 45 ℃ are uniformly mixed by a two-component polyurethane casting machine, and then are cast into a lockable mold preheated to 65 ℃, wherein the volume of an inner cavity is 868cm3The mold is filled with the mixture with the total mass of 564.2g, the mold filled with the mixture is placed at 65 ℃ for curing for 10 minutes, the mold is filled with the mixture after expansion molding, and the polyurethane microporous elastic cushion plate is molded in the mold.
Comparative example 6
(1) 15 parts of PTMEG1000, 51 parts of PTMEG2000, 24.4 parts of EP330, 8.3 parts of BDO and 0.23 part of H2Mixing O, 0.9 part of AK7703, 0.14 part of BDMAE and 0.03 part of T-12 uniformly to obtain a component A;
mixing 50 parts of MDI, 30 parts of PTMEG1000 and 20 parts of PTMEG2000, and stirring and reacting for 4 hours at 85 ℃ under the nitrogen protection atmosphere to obtain a component B with the-NCO value of 13.39;
(2) according to the mol ratio of active-H in the component A to-NCO group in the component B of 1:1, the component A preheated to 35 ℃ and the component B preheated to 45 ℃ are uniformly mixed by a two-component polyurethane casting machine, and then are cast into a lockable mold preheated to 65 ℃, wherein the volume of an inner cavity is 868cm3The mold of (2) was filled with a mixture of total mass 564.2g, and the mixture was poured into the moldAnd curing the mixed material mold at 65 ℃ for 10 minutes, and forming the polyurethane microporous elastic cushion plate in the mold after the mixture is expanded and formed and the mold is not filled.
Various performance tests are respectively carried out on the polyurethane microporous elastic base plate prepared in the embodiment and the comparative example according to corresponding standards, and the test results are detailed in table 1; the test method comprises the following steps of density test reference standard GB/T1033.1-2008, tensile strength and elongation at break test reference standard GB/T1040.3-2006, static stiffness test reference standard TB/T3395.1, compression set rate test reference standard GB/T10653 (70 ℃, 22h and 30% compression), load 300 ten thousand times fatigue test reference standard TB/T3395.1 appendix C (23 +/-2 ℃ for 24h, cyclic load 1 kN-35 kN, loading frequency 4Hz +/-1 Hz, and load cycle 3 multiplied by 106Second), the cold resistance test is referred to the standard TB/T3395.1 (-35 ℃, 16h static rigidity change rate), and the closed cell rate test is referred to the standard GB T10799-2008. From the test results in table 1, it can be seen that the high static stiffness polyurethane microporous elastic base plate prepared in examples 1-2 meets various performance index requirements for use in urban rail passenger lines, has good cold resistance, can improve the vibration reduction effect at low temperature, and meets the requirements for use at low temperature.
TABLE 1
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.