TECHNICAL FIELD

The present invention relates to a TPU material and a preparation process thereof, in particular to a TPU alloy material and a preparation process thereof, and belongs to the technical field of polymeric materials.

BACKGROUND ART

A thermoplastic polyurethane elastomer (TPU) is a type of polyurethane that can be plasticized by heating with no or little chemical cross-linking in the chemical structure, and has high strength, high modulus, better elasticity, excellent wear resistance, and good oil resistance in a wide range of hardness. TPU can generally be used to improve the performances of other materials due to its excellent elasticity, wear resistance, and the like.

However, when a thermoplastic polyurethane elastomer (TPU) is modified with polypropylene (PP), SEBS, EVA, ethylene-octene copolymer (POE), and the like, there is a problem of poor compatibility, and a compatibilizer is required. A general method comprises synthesizing TPU first; grafting a modified material with a compatibilizer, such as SEBS-g-MAH, EVA-g-MAH or POE-g-MAH; mixing the modified material and TPU uniformly in a high-speed mixer; and then extruding through a twin-screw extruder followed by granulation. Since the compatibilizer generally has a low grafting ratio and is physically compatible, a relatively large amount of compatibilizer is generally required to obtain a relatively good effect. Meanwhile, the requirements on the production process and equipment are relatively high.

SUMMARY OF INVENTION

In view of the shortcomings in the methods for preparing existing TPU modified materials, the present invention provides a process for preparing a TPU alloy material by in-situ compatibilization.

A technical solution of the present invention for solving the above technical problems is as follows:

A process for preparing a TPU alloy material through in-situ compatibilization, comprises the following steps:

1) adding premixed 100 parts by weight of TPU raw material into a feeding port of a twin-screw extruder; adding 5 to 95 parts by weight of an alloy component and 0.1 to 10 parts by weight of a dual-active substance into the twin-screw extruder through a lateral feeding port without a particular order for either of them; adding 0.1 to 5 parts by weight of an auxiliary reagent to the TPU raw material or the mixture of the alloy component and the dual-active substance, wherein the alloy component is one of a polyolefin material and a thermoplastic polymer material having reactivity, wherein the dual-active substance is a substance containing a group reactive with the TPU raw material and a group reactive with the alloy component, and wherein the auxiliary reagent comprises an initiator;

2) controlling a temperature of a reaction zone of the twin-screw extruder at 50° C. to 250° C., and granulating the extruded material by underwater cutting; and

3) drying the granulated product obtained in step 2) to obtain the TPU alloy material.

In further embodiments, the dual-active substance is a compound containing one or more of an anhydride group, carboxyl (—COOH), hydroxyl (—OH), amino (—NH or —NH2), an isocyanate group (—NCO), and an epoxy group.

In further embodiments, the dual-active substance is one of maleic anhydride, glycidyl methacrylate, acrylic acid, methyl methacrylate, butyl acrylate, acrylamide, allyl polyethylene glycol, amino acid, and epoxy resin.

In further embodiments, the thermoplastic polymer material having reactivity refers to one of polyamide, ABS resin, Thermoplastic elastomers (TPE), and polyacrylate.

In further embodiments, the polyolefin material is one of Styrene Ethylene Butylene Styrene (SEBS), Poly (styrene-butadiene-styrene) (SBS), polypropylene (PP), polyethylene (PE), ethylene-vinyl acetate (EVA), polyolefin elastomer (POE), and ethylene propylene diene monomer rubber (EPDM).

In further embodiments, the TPU raw material comprises a polymeric polyol, a chain extender, and an isocyanate.

In further embodiments, the polymeric polyol is one or more of a polyester polyol, a polyether polyol, and a hydroxyl terminated polybutadiene diol, and the chain extender is a small molecule diol or diamine having 12 carbon atoms or fewer.

In further embodiments, the chain extender is one or more of ethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, neopentyl glycol, and dipropylene glycol; the isocyanate is one or more of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), and xylylene diisocynate (XDI).

In further embodiments, the auxiliary reagent further comprises an antioxidant, a lubricant, and an UV-resistant additive.

In further embodiments, a rotation speed of the screw extruder in step 2) is controlled at 80 rpm to 400 rpm, and a temperature in a cooling zone is controlled at 90° C. to 110° C.

The present invention may include one or more of the following beneficial effects:

1) The TPU and the alloy materials are linked with chemical bonds using dual-active substances, thereby overcoming the compatibility problem between the TPU and the alloy materials, such that the products not only have excellent mechanical properties, wear-resisting properties, chemical resistance, high/low temperature resistance (tolerance), easy processing properties, and other performances of the TPU materials, but also can improve the binding performance with other materials, and thus the performances of the final product can be improved.

2) The synthesis of TPU, the in-situ compatibilization using the dual-active substance, and the mixing of the TPU and the alloy material are all achieved in one step in the twin-screw reaction extrusion process. Therefore, the production process is simplified.

DETAILED DESCRIPTION

The principles and features of the present invention are described below in conjunction with the following examples, which are merely intended to illustrate the invention and are not intended to limit the scope of the present invention.

