Polyester ether aliphatic ETPU easy to weld and its preparation and application

Abstract

The present invention discloses a polyester ether aliphatic polyurethane (ETPU) that is easy to weld and form, as well as its preparation method and application. The preparation method comprises: mixing and reacting at least one polyester polyol with an aliphatic diisocyanate I to obtain a prepolymer A; mixing and reacting at least one polyether polyol with an aliphatic diisocyanate II to obtain a prepolymer B; introducing prepolymer A, prepolymer B, a chain extender, and an optional catalyst into an extruder, reacting and extruding, and granulating to obtain aliphatic TPU beads; introducing the aliphatic TPU beads, a foaming agent, and water into a high-pressure vessel, stirring to form a suspension, and then heating to 80-180°C, directly releasing the pressure or maintaining the pressure at 50-200 bar for a period of time, and then releasing the pressure to remove the material to obtain a polyester ether aliphatic ETPU that is easy to weld and form. The polyester ether aliphatic ETPU foam product prepared by this molding has lower compression set and higher delamination tear strength.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoplastic polyurethane elastomer (TPU) foam materials, and in particular to polyester ether aliphatic foamed thermoplastic polyurethane elastomer beads (ETPU) that are easy to weld and form, as well as a preparation method and application thereof. Background Art

[0002] TPU is a semi-crystalline polymer material prepared by combining diisocyanate, long-chain diol and short-chain diol in a certain proportion on a belt system or in a reaction extruder. It has excellent mechanical properties, excellent heat and chemical resistance, and excellent wear resistance. Due to the diversity of its raw material formula, by adjusting the proportion of each raw material, products with a very wide range of hardness can be obtained.

[0003] ETPU can be obtained by using thermoplastic polyurethane elastomer beads as a matrix and filling a large number of bubbles inside the thermoplastic polyurethane elastomer beads through extrusion foaming granulation or high-pressure autoclave foaming.

[0004] Patent CN101370861B, an earlier invention patent for ETPU preparation, describes the process of impregnating thermoplastic polyurethane elastomer beads with a Shore hardness of 44-84A with a foaming agent under high pressure and high temperature, followed by pressure relief to produce the foamed thermoplastic polyurethane elastomer beads. Products molded from these foamed thermoplastic polyurethane elastomer beads offer a range of advantages, including low density, thermal and sound insulation, high specific strength, high elasticity, and cushioning. Consequently, they are widely used in packaging, industry, agriculture, transportation, military, aerospace, and daily necessities.

[0005] Aliphatic TPU refers to the diisocyanate used to produce TPU, which is an aliphatic diisocyanate, such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), hydrogenated phenylmethane diisocyanate (HDI), etc. 12 MDI), cyclohexyl dimethylene diisocyanate (H6XDI), cyclohexyl diisocyanate, etc.

[0006] Invention patent CN110183843B discloses a yellowing-resistant thermoplastic polyurethane foam material and a preparation method thereof, wherein a thermoplastic polyurethane elastomer is prepared by reacting an aliphatic diisocyanate, a chain extender, a polyol, an antioxidant, a UV absorber and a UV light stabilizer, and then aliphatic ETPU is prepared by autoclave foaming. It is disclosed that aliphatic ETPU has excellent yellowing resistance.

[0007] Invention patent CN112940488B discloses a thermoplastic polyurethane foam product with high flatness, its preparation method and application. The foamed aliphatic thermoplastic polyurethane elastomer beads are prepared by physical gas foaming of aliphatic thermoplastic polyurethane elastomer beads with a melting range of 20-50°C and a melting point of 90-160°C, and then the foamed aliphatic thermoplastic polyurethane elastomer beads are welded by heating with a heat source. It is disclosed that the prepared aliphatic ETPU product has high flatness and high resilience.

[0008] However, it has been discovered that current aliphatic ETPU products suffer from either high compression set or poor breakage resistance. Therefore, there is an urgent need to address the technical challenges of reducing the compression set and improving the delamination tear strength of aliphatic ETPU. Furthermore, it is also necessary to ensure that the resulting aliphatic ETPU can be easily welded and molded, thereby enabling the production of aliphatic ETPU foam products with high tensile strength and high elongation at break. Summary of the Invention

[0009] To address the above-mentioned technical problems and shortcomings in the art, the present invention provides a polyester ether aliphatic ETPU that is easily weldable, as well as a preparation method and application thereof. The polyester ether aliphatic ETPU of the present invention not only has excellent weldability (e.g., steam molding), but also has more uniform cell size. The polyester ether aliphatic ETPU foam products prepared therefrom have lower compression set and higher delamination tear strength.

[0010] In a first aspect, the present invention provides a method for preparing a polyester ether aliphatic ETPU that is easy to weld and form, comprising:

[0011] Mixing and reacting at least one polyester polyol with aliphatic diisocyanate I to obtain a prepolymer A;

[0012] Mixing and reacting at least one polyether polyol with an aliphatic diisocyanate II to obtain a prepolymer B;

[0013] Prepolymer A, prepolymer B, chain extender and optionally added catalyst (i.e., catalyst may be added or not) are put into an extruder, reacted, extruded, and granulated to obtain aliphatic TPU beads;

[0014] The aliphatic TPU beads, foaming agent and water are put into a high-pressure container, stirred to form a suspension, and then heated to 80-180°C. The pressure is directly released or the pressure is maintained at 50-200 bar for a period of time (for example, not more than 180 minutes, etc.), and then the pressure is released and the material is taken out to obtain the polyester ether aliphatic ETPU that is easy to weld and form.

[0015] The preparation of prepolymer A and prepolymer B can be carried out using existing technology and can be carried out in an apparatus for preparing prepolymers known to those skilled in the art, such as a heatable / coolable stirred tank, a reactive extruder, etc., and can be carried out at a temperature known to those skilled in the art, such as 20°C to 250°C.

[0016] The aliphatic diisocyanate I and the aliphatic diisocyanate II can be independently selected from at least one of hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated phenylmethane diisocyanate, cyclohexyl dimethylene diisocyanate, and cyclohexyl diisocyanate, preferably hexamethylene diisocyanate.

[0017] The catalyst may include at least one of stannous octoate, dibutyltin laurate, and an organic bismuth catalyst. When the catalyst is added, the amount of the catalyst may be 0.00001 to 0.1 parts by weight per 100 parts by weight of the total raw materials, where the total raw materials include the polyester polyol, the polyether polyol, the aliphatic diisocyanate I, the aliphatic diisocyanate II, and the chain extender.

[0018] The temperature of the reactive extrusion may be 80-260°C.

[0019] The usage ratio of the prepolymer A to the prepolymer B is 1:0.25-1.5 based on the mass ratio of the polyester polyol to the polyether polyol.

[0020] In the present invention, the polyester polyol and the polyether polyol may not be particularly limited. For example, the number average molecular weight of the polyester polyol may be 600-4000 g / mol, and further may be 600-3000 g / mol. Specifically, it may be a polyester diol, which may be prepared, for example, from a dicarboxylic acid having 2 to 12 carbon atoms, preferably 4 to 10 carbon atoms, and a diol. Examples of usable dicarboxylic acids are: aliphatic dicarboxylic acids, such as at least one of succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, and sebacic acid; and / or aromatic dicarboxylic acids, such as at least one of phthalic acid, isophthalic acid, and terephthalic acid. The dicarboxylic acids may be used alone or in the form of a mixture, for example, in the form of a mixture of succinic acid, sebacic acid, and adipic acid. The diol may be a diol having 2 to 10 carbon atoms, preferably 2 to 6 carbon atoms, such as at least one of ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, and dipropylene glycol. The diol may be used alone or in a mixture, such as a 1,4-butanediol mixture and / or a 1,3-propanediol mixture. The polyether polyol may have a number average molecular weight of 600-2000 g / mol, and may specifically be polytetrahydrofuran diol. The polyester polyol may also include polycaprolactone diol, etc., and may have a number average molecular weight of 600-3000 g / mol.

[0021] In the present invention, the chain extender is not particularly limited. For example, the chain extender can be a small molecule diol, such as a diol having 2 to 6 carbon atoms, such as ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, dipropylene glycol, etc., or a mixture of several thereof.

[0022] Based on the total mass of the polyester polyol, the polyether polyol, the aliphatic diisocyanate I, the aliphatic diisocyanate II and the chain extender being 100%, the total usage of the aliphatic diisocyanate I, the aliphatic diisocyanate II and the chain extender may be 20%-50%.

[0023] The molar ratio of the polyester polyol to the aliphatic diisocyanate I may be consistent with the molar ratio of the polyether polyol to the aliphatic diisocyanate II.

[0024] The total molar ratio of NCO groups and hydroxyl groups of the polyester polyol, the polyether polyol, the aliphatic diisocyanate I, the aliphatic diisocyanate II, and the chain extender may be 0.9-1.1:1.

[0025] The preparation method of the first aspect may adopt supercritical physical foaming. The foaming agent may include at least one of nitrogen and carbon dioxide.

[0026] In a second aspect, the present invention provides a polyester ether aliphatic ETPU that is easy to weld and mold, which is prepared by the preparation method described in the first aspect.

[0027] In a third aspect, the present invention provides the use of the polyester ether aliphatic ETPU described in the second aspect in the preparation of polyester ether aliphatic ETPU foam products by welding. The welding can be performed using steam. Furthermore, the steam pressure can be 0.7-1.8 bar, for example, 1.2 bar, 1.3 bar, 1.6 bar, etc.

[0028] In a fourth aspect, the present invention provides a polyester ether aliphatic ETPU foam product, produced by welding and molding raw materials including the polyester ether aliphatic ETPU described in the second aspect. The welding and molding can be performed using steam. Furthermore, the steam pressure can be 0.7-1.8 bar, for example, 1.2 bar, 1.3 bar, 1.6 bar, etc.

[0029] In a fifth aspect, the present invention provides a method for preparing a polyester ether aliphatic ETPU foam product, comprising:

[0030] The polyester ether aliphatic ETPU described in the second aspect is welded and formed in a mold to obtain the polyester ether aliphatic ETPU foam product.

[0031] In the preparation method of the polyester ether aliphatic ETPU foam product described in the fifth aspect, water vapor can be used for welding molding. Further, the water vapor pressure can be 0.7-1.8 bar, such as 1.2 bar, 1.3 bar, 1.6 bar, etc.

[0032] When the polyester ether aliphatic ETPU of the present invention is used for welding molding, the polyester ether aliphatic ETPU foam product with high elongation at break and high tensile strength can be obtained by good welding molding at a relatively low temperature (such as a relatively low water vapor pressure).

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention prepares polyester ether aliphatic ETPU through a specific process, which not only makes the foam cells more uniform, but also solves the problem that the current aliphatic ETPU products either have high compression deformation or poor damage resistance. The obtained foam products have both low compression deformation and high delamination tear strength.

[0035] 2. The present invention prepares aliphatic TPU beads by separate prepolymerization of polyester and polyether, and then chain extension, and then prepares polyester ether aliphatic ETPU by foaming. The prepared polyester ether aliphatic ETPU has better weldability (such as steam molding, etc.) than polyester ether aliphatic ETPU that is directly reacted without separate prepolymers, and the physical properties of the molded products (elongation at break, tensile strength, etc.) are better. The polyester ether aliphatic TPU synthesized by separate pre-polymerization of polyester polyether and then chain extension has a more uniform hard segment structure on the one hand, and weakens the difference in the reaction activity of polyester polyether diols on the other hand. The prepared polyester ether aliphatic TPU molecular chain segment composition is more uniform, and the phase separation of polyester polyether TPU chain segments is weakened, thereby reducing the temperature required for the welding molding of polyester ether aliphatic ETPU after foaming (the water vapor molding pressure is reduced). In addition, the physical properties of the molded products, such as the elongation at break and tensile strength, are greatly improved. At the same time, the prepared polyester ether aliphatic TPU has a more uniform hard segment structure. During supercritical physical gas foaming, the crystallization of the hard segment serves as the nucleation point, and the gas nucleation point distribution is more uniform, thereby obtaining a more uniform pore size of the polyester ether aliphatic ETPU. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention and are not intended to limit the scope of the invention. The operating methods in the following examples where no specific conditions are specified are generally performed under conventional conditions or as recommended by the manufacturer.

[0037] Note: The amount of blowing agent added during foaming is always excessive, and the foaming pressure setting requirement is controlled by venting during the foaming process. Due to differences in TPU raw material components or production processes, and to achieve the desired bulk density, the foaming temperatures required for preparing aliphatic ETPU in the Examples and Comparative Examples vary.

[0038] Example 1

[0039] The raw material ratio is designed according to the following formula: the mass ratio of the polyester polyol in step (1) to the polyether polyol in step (2) is 1:1, the mass percentage of the added aliphatic diisocyanate and the chain extender to the total amount of the raw materials added (i.e., the total amount of the polyester polyol, polyether polyol, aliphatic diisocyanate, and chain extender, the same below) is 33%. The molar ratio of NCO groups to hydroxyl groups in the total amount of the raw materials added is 0.99:1.

[0040] More specifically, a method for preparing polyester ether aliphatic ETPU and steam molded products thereof comprises the steps of:

[0041] (1) 50 parts by weight of polybutylene glycol adipate diol with a number average molecular weight of 1000 g / mol and 18.9 parts by weight of HDI were mixed and reacted at a reaction temperature of 80° C. to obtain prepolymer A.

[0042] (2) 50 parts by weight of polytetrahydrofuran diol with a number average molecular weight of 1000 g / mol and 18.9 parts by weight of HDI were mixed and reacted at a reaction temperature of 80° C. to obtain prepolymer B.

[0043] (3) All the prepolymer A of step (1), all the prepolymer B of step (2), 11.4 parts by weight of 1,4-butanediol, and 0.05 parts by weight of an organic bismuth catalyst were put into an extruder for reaction extrusion. The extruder temperature was set as follows: zones 1 and 2 were both 150° C., zones 3, 4, and 5 were all 220° C., zones 6, 7, and 8 were all 130° C., zones 9 and 10 were all 100° C., the die head temperature was 220° C., the screw speed was 200 rpm, and underwater granulation was performed to obtain aliphatic TPU beads.

[0044] (4) 10 kg of the aliphatic TPU beads prepared in step (3), 4 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The suspension was then heated to 120° C. and the pressure was maintained at 85 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain polyester ether aliphatic ETPU beads. The performance of the beads was evaluated, as shown in Table 1.

[0045] The polyester ether aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 1.6 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0046] Example 2

[0047] The raw material ratio is designed as follows: the mass ratio of the polyester polyol in step (1) to the polyether polyol in step (2) is 1:0.25, the mass percentage of the added aliphatic diisocyanate and the chain extender to the total amount of the raw materials added is 20%. The molar ratio of NCO groups to hydroxyl groups in the total raw materials added is 0.95:1.

[0048] More specifically, a method for preparing polyester ether aliphatic ETPU and steam molded products thereof comprises the steps of:

[0049] (1) 80 parts by weight of polybutylene glycol adipate diol with a number average molecular weight of 3000 g / mol and 13.1 parts by weight of HDI were mixed and reacted at a reaction temperature of 120° C. to obtain prepolymer A.

[0050] (2) 20 parts by weight of polytetrahydrofuran diol with a number average molecular weight of 2000 g / mol and 4.9 parts by weight of HDI were mixed and reacted at a reaction temperature of 120° C. to obtain prepolymer B.

[0051] (3) All the prepolymer A of step (1), all the prepolymer B of step (2), 7.0 parts by weight of 1,4-butanediol, and 0.02 parts by weight of stannous octoate catalyst were put into an extruder for reaction extrusion. The extruder temperature was set as follows: 150° C. for zone 1 and zone 2, 200° C. for zone 3, zone 4, and zone 5, 130° C. for zone 6, zone 7, and zone 8, and 100° C. for zone 9 and zone 10. The die head temperature was 200° C., the screw speed was 200 rpm, and underwater granulation was performed to obtain aliphatic TPU beads.

[0052] (4) 10 kg of the aliphatic TPU beads prepared in step (3), 6 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The suspension was then heated to 100° C. and the pressure was maintained at 150 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain polyester ether aliphatic ETPU beads. The performance of the beads was evaluated, as shown in Table 1.

[0053] The polyester ether aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 0.7 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0054] Example 3

[0055] The raw material ratio is designed as follows: the mass ratio of the polyester polyol in step (1) to the polyether polyol in step (2) is 1:1.5, the mass percentage of the added aliphatic diisocyanate and the chain extender to the total amount of the raw materials added is 50%. The molar ratio of NCO groups to hydroxyl groups in the total raw materials added is 1.05:1.

[0056] More specifically, a method for preparing polyester ether aliphatic ETPU and steam molded products thereof comprises the steps of:

[0057] (1) 40 parts by weight of polyethylene glycol adipate diol with a number average molecular weight of 600 g / mol and 28.7 parts by weight of HDI were mixed and reacted at a reaction temperature of 70° C. to obtain prepolymer A.

[0058] (2) 60 parts by weight of polytetrahydrofuran diol with a number average molecular weight of 600 g / mol and 43.0 parts by weight of HDI were mixed and reacted at a reaction temperature of 70° C. to obtain prepolymer B.

[0059] (3) All the prepolymer A of step (1), all the prepolymer B of step (2), 28.3 parts by weight of 1,6-hexanediol, and 0.01 parts by weight of an organic bismuth catalyst were put into an extruder for reaction extrusion. The extruder temperature was set as follows: 150° C. for zones 1 and 2, 220° C. for zones 3, 4, and 5, 130° C. for zones 6, 7, and 8, and 100° C. for zones 9 and 10. The die temperature was 230° C., the screw speed was 200 rpm, and underwater granulation was performed to obtain aliphatic TPU beads.

[0060] (4) 10 kg of the aliphatic TPU beads prepared in step (3), 4 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The suspension was then heated to 125° C. and the pressure was maintained at 70 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain polyester ether aliphatic ETPU beads. The performance of the beads was evaluated, as shown in Table 1.

[0061] The polyester ether aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 1.8 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0062] Example 4

[0063] The raw material ratio is designed as follows: the mass ratio of the polyester polyol in step (1) to the polyether polyol in step (2) is 1.5:1, the mass percentage of the added aliphatic diisocyanate and the chain extender to the total amount of the raw materials added is 30%. The molar ratio of NCO groups to hydroxyl groups in the total raw materials added is 1.01:1.

[0064] More specifically, a method for preparing polyester ether aliphatic ETPU and steam molded products thereof comprises the steps of:

[0065] (1) 60 parts by weight of polycaprolactone diol with a number average molecular weight of 1000 g / mol and 20.6 parts by weight of HDI were mixed and reacted at a reaction temperature of 150° C. to obtain prepolymer A.

[0066] (2) 40 parts by weight of polytetrahydrofuran diol with a number average molecular weight of 1000 g / mol and 13.7 parts by weight of HDI were mixed and reacted at a reaction temperature of 150° C. to obtain prepolymer B.

[0067] (3) All the prepolymer A of step (1), all the prepolymer B of step (2), 8.5 parts by weight of 1,4-butanediol, and 0.005 parts by weight of an organic bismuth catalyst were put into an extruder for reaction extrusion. The extruder temperature was set as follows: 150° C. for zones 1 and 2, 200° C. for zones 3, 4, and 5, 130° C. for zones 6, 7, and 8, and 100° C. for zones 9 and 10. The die temperature was 220° C., the screw speed was 200 rpm, and underwater granulation was performed to obtain aliphatic TPU beads.

[0068] (4) 10 kg of the aliphatic TPU beads prepared in step (3), 4 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The suspension was then heated to 110° C. and the pressure was maintained at 90 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain polyester ether aliphatic ETPU beads. The performance of the beads was evaluated, as shown in Table 1.

[0069] The polyester ether aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 1.2 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0070] Comparative Example 1

[0071] Without step-by-step prepolymerization, polyester polyol, polyether polyol, aliphatic diisocyanate and chain extender are directly added to the extruder for reaction. The specific steps are as follows:

[0072] The raw material ratio was designed as follows: the mass ratio of polyester polyol to polyether polyol was 1:1, the mass percentage of aliphatic diisocyanate and chain extender to the total raw material addition was 33%. The molar ratio of NCO groups to hydroxyl groups in the total raw material addition of polyester polyol, polyether polyol, aliphatic diisocyanate, and chain extender was 0.99:1.

[0073] More specifically, a method for preparing aliphatic ETPU and steam molded products thereof comprises the steps of:

[0074] (1) 50 parts by weight of polytetramethylene glycol adipate diol with a number average molecular weight of 1000 g / mol, 50 parts by weight of polytetramethylene glycol with a number average molecular weight of 1000 g / mol, 37.8 parts by weight of HDI, 11.4 parts by weight of 1,4-butanediol, and 0.05 parts by weight of an organic bismuth catalyst are put into an extruder for reaction extrusion. The extruder temperature is set as follows: the first and second zones are both 150° C., the third, fourth, and fifth zones are all 220° C., the sixth, seventh, and eighth zones are all 130° C., the ninth and tenth zones are all 100° C., the die head temperature is 220° C., the screw speed is 200 rpm, and underwater granulation is performed to obtain aliphatic TPU beads;

[0075] (2) 10 kg of the aliphatic TPU beads prepared in step (1), 4 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The suspension was then heated to 130° C. and maintained at a pressure of 85 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain aliphatic ETPU beads, the properties of which were evaluated as shown in Table 1.

[0076] The aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 2.1 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0077] Compared with Example 1, it can be found that in order to obtain higher quality aliphatic ETPU beads and foam products thereof in this comparative example, the foaming process needs to be heated to a higher temperature and the steam molding process requires a higher steam pressure.

[0078] Comparative Example 2

[0079] Only polyester polyol is added without adding polyether polyol, specifically as follows:

[0080] The raw material ratio is designed as follows: the mass percentage of the added amount of aliphatic diisocyanate and chain extender to the total added amount of raw materials is 33%. The molar ratio of NCO groups to hydroxyl groups in the total raw material added of polyester polyol, aliphatic diisocyanate and chain extender is 0.99:1.

[0081] More specifically, a method for preparing aliphatic ETPU and steam molded products thereof comprises the steps of:

[0082] (1) 100 parts by weight of polybutylene glycol adipate diol with a number average molecular weight of 1000 g / mol and 37.8 parts by weight of HDI were mixed and reacted at a reaction temperature of 80° C. to obtain prepolymer A.

[0083] (2) All the prepolymer A of step (1), 11.4 parts by weight of 1,4-butanediol, and 0.05 parts by weight of an organic bismuth catalyst were put into an extruder for reaction extrusion. The extruder temperature was set as follows: zones 1 and 2 were both 150° C., zones 3, 4, and 5 were all 220° C., zones 6, 7, and 8 were all 130° C., zones 9 and 10 were all 100° C., the die head temperature was 220° C., the screw speed was 200 rpm, and underwater granulation was performed to obtain aliphatic TPU beads.

[0084] (3) 10 kg of the aliphatic TPU beads prepared in step (2), 4 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The suspension was then heated to 123° C. while maintaining the pressure at 85 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain aliphatic ETPU beads, the properties of which were evaluated as shown in Table 1.

[0085] The aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 1.7 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0086] Comparative Example 3

[0087] Only polyether polyol is added without polyester polyol, specifically as follows:

[0088] The raw material ratio is designed as follows: the mass percentage of the added amount of aliphatic diisocyanate and chain extender to the total raw material added is 33%. The molar ratio of NCO groups to hydroxyl groups in the total raw material added of polyether polyol, aliphatic diisocyanate and chain extender is 0.99:1.

[0089] More specifically, a method for preparing aliphatic ETPU and steam molded products thereof comprises the steps of:

[0090] (1) 100 parts by weight of polytetrahydrofuran diol having a number average molecular weight of 1000 g / mol and 37.8 parts by weight of HDI were mixed and reacted at a reaction temperature of 80° C. to obtain prepolymer B.

[0091] (2) All the prepolymer B in step (1), 11.4 parts by weight of 1,4-butanediol, and 0.05 parts by weight of an organic bismuth catalyst were put into an extruder for reaction extrusion. The extruder temperature was set as follows: zones 1 and 2 were 150° C., zones 3, 4, and 5 were 220° C., zones 6, 7, and 8 were 130° C., zones 9 and 10 were 100° C., the die head temperature was 220° C., the screw speed was 200 rpm, and underwater granulation was performed to obtain aliphatic TPU beads.

[0092] (3) 10 kg of the aliphatic TPU beads prepared in step (2), 4 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The suspension was then heated to 112° C. and the pressure was maintained at 85 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain aliphatic ETPU beads. The performance of the beads was evaluated, as shown in Table 1.

[0093] The aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 1.3 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0094] Comparative Example 4

[0095] Only polyester polyol is added without adding polyether polyol, and no prepolymerization is performed. The specific steps are as follows:

[0096] The raw material ratio is designed as follows: the mass percentage of the added amount of aliphatic diisocyanate and chain extender to the total added amount of raw materials is 33%. The molar ratio of NCO groups to hydroxyl groups in the total raw material added of polyester polyol, aliphatic diisocyanate and chain extender is 0.99:1.

[0097] More specifically, a method for preparing aliphatic ETPU and steam molded products thereof comprises the steps of:

[0098] (1) 100 parts by weight of polybutylene glycol adipate diol with a number average molecular weight of 1000 g / mol, 37.8 parts by weight of HDI, 11.4 parts by weight of 1,4-butanediol, and 0.05 parts by weight of an organic bismuth catalyst were put into an extruder for reaction extrusion. The extruder temperature was set as follows: zones 1 and 2 were both 150°C, zones 3, 4, and 5 were all 220°C, zones 6, 7, and 8 were all 130°C, zones 9 and 10 were all 100°C, the die head temperature was 220°C, the screw speed was 200 rpm, and underwater granulation was performed to obtain aliphatic TPU beads.

[0099] (2) 10 kg of the aliphatic TPU beads from step (1), 4 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The temperature was then raised to 126° C., while maintaining the pressure at 85 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain aliphatic ETPU beads, the properties of which were evaluated, as shown in Table 1.

[0100] The aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 1.8 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0101] Comparative Example 5

[0102] Only polyether polyol is added without polyester polyol, and no prepolymerization is performed. The specific steps are as follows:

[0103] The raw material ratio is designed as follows: the mass percentage of the added amount of aliphatic diisocyanate and chain extender to the total raw material added is 33%. The molar ratio of NCO groups to hydroxyl groups in the total raw material added of polyether polyol, aliphatic diisocyanate and chain extender is 0.99:1.

[0104] More specifically, a method for preparing aliphatic ETPU and steam molded products thereof comprises the steps of:

[0105] (1) 100 parts by weight of polytetrahydrofuran diol with a number average molecular weight of 1000 g / mol, 37.8 parts by weight of HDI, 11.4 parts by weight of 1,4-butanediol, and 0.05 parts by weight of an organic bismuth catalyst were put into an extruder for reaction extrusion. The extruder temperature was set as follows: zones 1 and 2 were both 150°C, zones 3, 4, and 5 were all 220°C, zones 6, 7, and 8 were all 130°C, zones 9 and 10 were all 100°C, the die head temperature was 220°C, the screw speed was 200 rpm, and underwater granulation was performed to obtain aliphatic TPU beads.

[0106] (2) 10 kg of the aliphatic TPU beads prepared in step (1), 4 kg of carbon dioxide, and 20 kg of water were added to a 500 L autoclave to form a suspension. The suspension was then heated to 115° C. and the pressure was maintained at 85 bar. The suspension in the pressure vessel was discharged into the atmosphere and dried to obtain aliphatic ETPU beads having low compression set and high delamination tear strength. The performance of the beads was evaluated, as shown in Table 1.

[0107] The aliphatic ETPU beads obtained above were placed in a mold measuring 200 mm long, 100 mm wide, and 20 mm thick. Steam at 1.4 bar pressure was used to compress the mold by 10% along its thickness, causing the particles to bond and form. This molded foam product was then oven-dried at 70°C for 6 hours and then allowed to stand at room temperature for 2 hours. Its properties were evaluated, as shown in Table 1.

[0108] Table 1

[0109]

[0110] It can be seen from the data of Examples 1-4 and Examples 1-4 in Table 1 that the polyester ether aliphatic ETPU prepared by the technical solution of the present invention has a uniform pore size and a low steam molding pressure. The steam molded foam products have lower compression deformation and excellent mechanical strength, which can greatly increase the service life of the foam products.

[0111] Comparing the data of Example 1 and Comparative Example 1, under the condition of the same raw materials, the aliphatic ETPU foam size prepared by the preparation method of the technical solution of the present invention is more uniform, the required water vapor molding pressure is low, and the mechanical properties of the water vapor molded foam products are also better.

[0112] By comparing the data of Example 1 and Comparative Examples 2-5, it can be seen that the performance of the polyether ester aliphatic ETPU prepared by the technical solution of the present invention is more balanced and excellent. The polyether ester aliphatic ETPU steam molded products of the present invention have both low compression deformation and high mechanical properties.

[0113] Comparing the data of Comparative Examples 2 and 4, and Comparative Examples 3 and 5, under the same raw materials, the aliphatic TPU is synthesized by the prepolymer method, and the aliphatic ETPU prepared has more uniform foam size and improved performance.

[0114] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A method for preparing polyester ether aliphatic ETPU that is easy to weld and form, characterized in that: include: Mixing and reacting at least one polyester polyol with an aliphatic diisocyanate I to obtain a prepolymer A; Mixing and reacting at least one polyether polyol with an aliphatic diisocyanate II to obtain a prepolymer B; Prepolymer A, prepolymer B, chain extender and optionally added catalyst are put into an extruder, reacted, extruded and granulated to obtain aliphatic TPU beads; By using supercritical physical foaming, the aliphatic TPU beads, foaming agent and water are put into a high-pressure container, stirred to form a suspension, and then heated to 80-180°C. The pressure is directly released or the pressure is maintained at 50-200 bar for a period of time, and then the material is released and taken out to obtain the polyester ether aliphatic ETPU that is easy to weld and form.

2. The preparation method according to claim 1, characterized in that The aliphatic diisocyanate I and the aliphatic diisocyanate II are independently selected from at least one of hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated phenylmethane diisocyanate, cyclohexyl dimethylene diisocyanate, and cyclohexyl diisocyanate.

3. The preparation method according to claim 1, characterized in that The temperature of the reactive extrusion is 80-260°C.

4. The preparation method according to claim 1, characterized in that The usage ratio of the prepolymer A to the prepolymer B is 1:0.25-1.5 based on the mass ratio of the polyester polyol to the polyether polyol; The number average molecular weight of the polyester polyol is 600-4000 g / mol; The number average molecular weight of the polyether polyol is 600-2000 g / mol.

5. The preparation method according to claim 1, characterized in that Based on the total mass of the polyester polyol, the polyether polyol, the aliphatic diisocyanate I, the aliphatic diisocyanate II and the chain extender as 100%, the sum of the usage of the aliphatic diisocyanate I, the aliphatic diisocyanate II and the chain extender is 20%-50%.

6. The preparation method according to claim 1, characterized in that The molar ratio of the polyester polyol to the aliphatic diisocyanate I is consistent with the molar ratio of the polyether polyol to the aliphatic diisocyanate II.

7. The preparation method according to claim 1, characterized in that The total molar ratio of NCO groups and hydroxyl groups of the polyester polyol, the polyether polyol, the aliphatic diisocyanate I, the aliphatic diisocyanate II and the chain extender is 0.9-1.1:

1.

8. The preparation method according to claim 1, characterized in that The foaming agent includes at least one of nitrogen and carbon dioxide.

9. A polyester ether aliphatic ETPU that is easy to weld and mold, prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the polyester ether aliphatic ETPU according to claim 9 in preparing polyester ether aliphatic ETPU foam products by welding molding.

11. A polyester ether aliphatic ETPU foam product, characterized in that: It is prepared by welding and molding raw materials including the polyester ether aliphatic ETPU described in claim 9.

12. A method for preparing a polyester ether aliphatic ETPU foam product, characterized in that: include: The polyester ether aliphatic ETPU according to claim 9 is welded and formed in a mold to obtain the polyester ether aliphatic ETPU foam product.

13. The method for preparing the polyester ether aliphatic ETPU foam product according to claim 12, characterized in that: Use steam for welding; The water vapor pressure is 0.7-1.8 bar.

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