CN-122011738-A - TPU composite foam material with open-cell structure and preparation method thereof

Abstract

The application relates to the field of open-cell foam materials, in particular to a TPU composite foam material with an open-cell structure and a preparation method thereof, wherein the TPU composite foam material comprises, by weight, 60-90 parts of TPU, 10-40 parts of EVA and 0.5-2.5 parts of catalyst, and the catalyst is a mixture of zinc diethyl dithiocarbamate and bismuth trioxide. According to the preparation method, zinc diethyl dithiocarbamate and bismuth trioxide are compounded into a catalyst, and the catalyst is added into a system, so that the compatibility between TPU and EVA can be improved through two aspects of physical coordination bridging and catalytic transesterification, so that EVA is uniformly dispersed in a TPU matrix in smaller particles, the existence of EVA can serve as a pore opening agent, the aperture ratio of the TPU composite foaming material is improved, and the TPU composite foaming material with excellent performance is prepared.

Inventors

• BAO JINBIAO
• ZHENG XIAOPING
• WANG YUEMING

Assignees

• 宁波致微新材料科技有限公司

Dates

Publication Date

20260512

Application Date

20260410

Priority Date

20251029

Claims (8)

1. 1. The TPU composite foaming material with the open-cell structure is characterized by comprising the following components, by weight, 60-90 parts of TPU, 10-40 parts of EVA and 0.5-2.5 parts of catalyst; The catalyst is a mixture of zinc diethyl dithiocarbamate and bismuth trioxide.
2. 2. An open cell TPU composite foam according to claim 1, characterised in that the mixing molar ratio of zinc diethyldithiocarbamate to bismuth trioxide is 0.8-1.2:1.
3. 3. An open cell TPU composite foam according to claim 1, characterized in that the particle size of the bismuth trioxide is 1-3 μm.
4. 4. An open cell TPU composite foam according to claim 1, characterised in that 0.1-1 parts of an antioxidant is added, said antioxidant being a mixture of distearyl thiodipropionate and antioxidant 1135.
5. 5. The open cell TPU composite foam material according to claim 4, wherein the mixing mass ratio of distearyl thiodipropionate to antioxidant 1135 is 1:1-2.
6. 6. An open cell TPU composite foam material according to claim 1, wherein said TPU is a polyester TPU.
7. 7. A process for the preparation of an open cell TPU composite foam material according to any one of claims 1-6, comprising the steps of: s1, banburying TPU, EVA and a catalyst according to the formula amount to obtain a banburying product; S2, tabletting the banburying product to obtain a sheet; S3, introducing high-pressure gas into the sheet at the temperature of 125-145 ℃ and the pressure of the high-pressure gas is 12-15MPa; and S4, decompressing after the high-pressure gas in the sheet is saturated, and obtaining the TPU composite foaming material with the open-cell structure.
8. 8. The method for preparing a TPU composite foam material with an open cell structure according to claim 7, wherein in S1, an antioxidant with a formula amount, TPU, EVA and a catalyst are added for banburying, and a banburying product is obtained.

Description

TPU composite foam material with open-cell structure and preparation method thereof Technical Field The application relates to the field of open-cell foam materials, in particular to a TPU composite foam material with an open-cell structure and a preparation method thereof. Background Thermoplastic Polyurethane (TPU) and ethylene-vinyl acetate copolymer (EVA) are two high molecular polymers that are widely used in the field of foamed materials. TPU is favored because of its excellent abrasion resistance, high elasticity, good mechanical strength and oil resistance, while EVA has certain advantages in terms of its free flexibility, low processing temperature and certain foaming properties by itself. Thus, one skilled in the art often blends TPU and EVA to make a foamed material. However, in the actual blending preparation process, because of the unsatisfactory compatibility between the TPU and the EVA, the EVA phase is difficult to form a fine and uniform dispersion form, but exists in the form of particles or agglomerates with relatively large size in the TPU matrix, which results in unsatisfactory open cell content of the TPU composite foam material, thereby limiting the application of the TPU composite foam material in high air permeability materials, protective cushioning materials and sound absorbing materials. In view of the above challenges, researchers are working to develop new catalyst systems that regulate the dispersion state of EVA in the TPU matrix by catalyzing the transesterification reaction, and increase the open cell content of the TPU composite foam. Disclosure of Invention In order to improve the compatibility between TPU and EVA and the aperture ratio of the TPU-EVA composite material, the application provides a TPU composite foaming material with an open-cell structure and a preparation method thereof. In a first aspect, the application provides a TPU composite foaming material with an open pore structure, which adopts the following technical scheme: the TPU composite foaming material with the open-cell structure comprises the following components, by weight, 60-90 parts of TPU, 10-40 parts of EVA and 0.5-2.5 parts of catalyst; The catalyst is a mixture of zinc diethyl dithiocarbamate and bismuth trioxide. By adopting the technical scheme, in the foaming process of the TPU composite foaming material, EVA can be used as a stress concentration point, so that a film is torn from the periphery of an EVA region to form a communicated open pore network, the aperture ratio of the TPU composite foaming material is improved, the rebound resilience is reduced, zinc ions in zinc diethyl dithiocarbamate and bismuth trioxide are compounded into a catalyst, and bismuth ions in zinc diethyl dithiocarbamate and bismuth trioxide are used as Lewis acids to form coordination bonds with carbonyl oxygen and amino nitrogen on TPU chains and ester carbonyl oxygen on EVA chains, so that the TPU and EVA molecular chains are pulled up, the molecular winding and interaction strength at two-phase interfaces are increased, and the interfacial tension is effectively reduced, so that the TPU and EVA two phases can be dispersed more uniformly. Under the condition of approaching the melting temperature, zinc diethyl dithiocarbamate and bismuth trioxide can catalyze transesterification reaction between the urethane group of TPU and the ester group of EVA to generate TPU-g-EVA grafted copolymer, so that the compatibility of TPU and EVA is effectively improved, and EVA can be stably dispersed in the TPU continuous phase in smaller and more uniform particle size. And the sulfur atom of the zinc diethyl dithiocarbamate has strong coordination capability, can coordinate with bismuth ions on the surface of bismuth trioxide to form stable Bi-S covalent coordination bonds, an inorganic-organic hybridization catalytic interface is constructed, an inorganic phase can activate carbonyl groups through electrostatic interaction or coordination, organic phase and organic molecular chains of TPU and EVA have van der Waals force or hydrophobic interaction, and molecular chains of two substrates can be specifically adsorbed. The double adsorption ensures that the ester group of TPU and the vinyl acetate group of EVA are simultaneously fixed near the active site of the catalytic interface, thereby obviously shortening the space distance between the two molecular chains, greatly reducing the steric hindrance of the transesterification reaction and accelerating the transesterification reaction process. Meanwhile, the organic chain segment of the zinc diethyl dithiocarbamate can form steric hindrance on the surface of the bismuth trioxide to prevent the aggregation of the bismuth trioxide particles, so that active sites are more uniformly distributed on an interface, and the catalytic efficiency is improved. Meanwhile, the existence of zinc diethyl dithiocarbamate and bismuth trioxide can also inhibit side reaction, the existence of zinc d