High-melt-stability TPEE system and preparation method thereof

Abstract

The invention discloses a high-melt-stability TPEE system and a preparation method thereof, and the high-melt-stability TPEE system for blow molding is obtained by melting and mixing raw materials including TPEE resin, an antioxidant, a chain extender, a catalyst, a modifier and a light stabilizing aid. In order to solve the technical problem that a blow molding TPEE resin melt is unstable, a double-screw melt extrusion method is adopted, and a mode of matching a chain extender, a catalyst and an antioxidant with a modifier is adopted, so that the melt stability of the material is improved, and the problem of melt breakage is solved, so that the blow molding requirement is met.

Description

Technical Field

[0001] The present invention belongs to advanced material technology and relates to a modified TPEE, specifically a high melt-stable TPEE system and a preparation method thereof, which improves the melt fracture phenomenon. Background Art

[0002] Thermoplastic polyester elastomer (TPEE) is a polymer with excellent performance. It is a two-block copolymer. The hard segment is composed of highly crystalline polyesters, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), etc., which mainly provide physical cross-linking points for the elastomer. At the same time, the high rigidity of the hard segment molecular chain gives the material excellent temperature resistance; the soft segment is composed of flexible polyethers with a certain molecular weight, such as polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetramethylene glycol (PTMG), which gives the material excellent elasticity within the operating temperature range.

[0003] TPEE has excellent wear resistance, and because the polyester hard segment has good resistance to chemical reagents (especially acid and alkali resistance, etc.). The polyether structure also gives TPEE good low-temperature performance, which is suitable for high-pressure and high-temperature environments such as automobile intake pipes and turbocharger pipes.

[0004] The structural characteristics of TPEE determine that the melt is unstable and breaks during the blow molding of the resin. This characteristic makes it difficult to meet the requirements of the blow molding process for large special components. Research and development of blow molding grade TPEE is very necessary to expand the application field of TPEE. The prior art adds nanorod-shaped styrene-methyl methacrylate copolymer to the TPEE after viscosity enhancement. Since the nanorod-shaped styrene-methyl methacrylate copolymer has a strong orientation effect, the extrusion swelling effect of TPEE can be greatly reduced; however, the nanorod-shaped styrene-methyl methacrylate copolymer significantly increases the cost and the improvement effect on melt fracture is unclear. The prior art discloses TPEE-based film materials, including blow molding grade TPEE, TPU, plasticizer, antioxidant, lubricant, hydrolysis stabilizer, montmorillonite, which still has good softness at minus 20°C; however, it uses TPU and can only prepare thin films, and its low temperature resistance is insufficient, which is not suitable for the application of automotive parts. The applicant previously disclosed a low melt index and high heat and oxygen aging resistance TPEE modified material and a preparation method thereof, wherein the raw material TPEE resin, antioxidant, modifier, catalyst and additive are melt mixed to obtain a product. Although the melt index of the material is reduced to below 1 g / 10min, the problem of melt fracture still occurs when it is used for blow molding of large automotive components, and the low temperature resistance performance needs to be improved. Summary of the invention

[0005] In order to solve the technical problem of unstable melt of TPEE resin in blow molding, the present invention adopts a twin-screw melt extrusion method, and adopts a chain extender, a catalyst and an antioxidant in combination with a modifier to improve the melt stability of the material and solve the problem of melt fracture to meet the blow molding needs, especially to meet the preparation requirements of blow molding-grade automotive dust covers.

[0006] The present invention adopts the following technical scheme.

[0007] A high melt stable TPEE system for blow molding comprises TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent, wherein the modifier comprises maleic anhydride grafted hydrogenated styrene-butadiene block copolymer.

[0008] The present invention discloses a method for preparing the high melt stable TPEE system for blow molding, wherein raw materials including TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent are melt-mixed to obtain the high melt stable TPEE system for blow molding.

[0009] Preferably, the high melt stable TPEE system for blow molding of the present invention is prepared from TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent.

[0010] In the present invention, the mass ratio of TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent is (60-90): (0.1-0.5): (0.5-5): (0.1-0.5): (8-20): (1-3); preferably, the mass ratio of TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent is (65-85): (0.1-0.4): (1-4): (0.2-0.4): (10-17): (1.5-2.5); further Preferably, the mass ratio of TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent is (70-85): (0.2-0.4): (2-3): (0.2-0.4): (13-16): (1.5-2); further preferably, the mass ratio of TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent is (75-82): (0.2-0.4): (2-3): (0.2-0.4): (13-16): (1.5-2).

[0011] In the present invention, the modifier is maleic anhydride grafted hydrogenated styrene-butadiene block copolymer, and the grafting ratio of MAH is 1.8-2.5%. Preferably, in the maleic anhydride grafted hydrogenated styrene-butadiene block copolymer, the grafting ratio of MAH is 2.0-2.3%. The present invention adopts a new formula, and on the basis of improving the TPEE melt index by the chain extender in the prior art, the melt stability of the material is improved by limiting the type of modifier and the grafting content, and the problem of melt fracture is solved to meet the blow molding requirements.

[0012] The invention discloses the application of the high melt stable TPEE system in solving the TPEE blow molding melt fracture problem.

[0013] The present invention discloses the application of the high melt-stable TPEE system for solving melt fracture in the preparation of or as a melt-stable TPEE blow molding material.

[0014] The present invention discloses the application of the high melt stable TPEE system in the preparation of TPEE materials.

[0015] The present invention discloses the application of the high melt stable TPEE system for solving melt fracture in the preparation of blow molding TPEE materials.

[0016] The invention discloses an automobile blow molding part, which is prepared by blow molding the high-melt stable TPEE system for blow molding.

[0017] In the present invention, the blow-molded TPEE material or automobile blow-molded part includes a blow-molded grade automobile dust cover.

[0018] In the present invention, the antioxidant includes an amine antioxidant and / or a hindered phenol antioxidant.

[0019] In the present invention, the chain extender includes an epoxy chain extender, which can react with the hydroxyl group and the terminal carboxyl group of the TPEE molecule, and the epoxy chain extender with PBT as a carrier can be selected.

[0020] In the present invention, the catalyst uses one or more of titanium diboride, zinc chloride and zinc stearate to catalyze the reaction with the chain extender to play a coordination role.

[0021] In the present invention, the auxiliary agent includes a light stabilizer and a pigment; preferably, the light stabilizer includes a benzotriazole light stabilizer.

[0022] The present invention adopts a conventional twin-screw melt extrusion method to prepare a high melt-stable TPEE system for blow molding by melt mixing TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent. The chain extender is used in combination with auxiliary agents such as catalyst and modifier to achieve suitable melting properties, especially to improve the melt stability of blow-molded TPEE, solve the melt fracture phenomenon, and improve the performance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a real photo of 7215.

[0024] Figure 2 The capillary rheology test results of the particles in the examples at 230°C are shown.

[0025] Figure 3 This is a photo of the conventionally prepared test piece of Example 3, with no cracks.

[0026] Figure 4 This is a photo of the conventionally prepared test piece of Comparative Example 2, which is cracked. DETAILED DESCRIPTION

[0027] The present invention adopts a one-step molding method of twin-screw melt extrusion with high processing efficiency, uses a chain extender in combination with a catalyst, a modifier, etc. to achieve suitable melting properties, alleviates the melt fracture phenomenon associated with blow molding, and improves the performance of the material. During the specific processing, all materials are mixed and directly enter the twin-screw extrusion melt processing; the chain extender, catalyst, antioxidant, light stabilizer, etc. can also be mixed together and added through a separate weight-loss metering scale. As an example, the diameter of the twin-screw extruder used is 63mm, the aspect ratio is 56:1, the processing temperature is 180℃-240℃, the screw speed is 200rpm, and the feeding speed is 250rpm.

[0028] The high melt stable TPEE system for blow molding of the present invention is prepared from TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent. The formula composition is as follows in terms of mass percentage: Antioxidant 0.2-0.4% Chain extender 1-4% Catalyst 0.2-0.3% Modifier 10-20% Additives 1-3% TPEE resin balance Preferably, by mass percentage, the formula is as follows: Antioxidant 0.3% Chain extender 2-3% Catalyst 0.3% Modifier 13-16% Additive 2% TPEE resin balance.

[0029] In the present invention, the modifier is preferably a maleic anhydride grafted hydrogenated styrene-butadiene block copolymer, wherein the grafting ratio of MAH is 1.8-2.5%, and preferably, in the maleic anhydride grafted hydrogenated styrene-butadiene block copolymer, the grafting ratio of MAH is 2.0-2.3%. The test method of the grafting rate is the acid-base titration method, which is a conventional technique.

[0030] In the present invention, the antioxidant includes an amine antioxidant and / or a hindered phenol antioxidant.

[0031] In the present invention, the chain extender includes an epoxy chain extender, which may be glyceryl methacrylate (GMA), triglycidyl isocyanurate (TGIC), etc., which reacts with the hydroxyl group and the terminal carboxyl group of the TPEE molecule.

[0032] In the present invention, the catalyst uses one or more of titanium diboride, zinc chloride and zinc stearate to catalyze the reaction with the chain extender to play a coordination role.

[0033] In the present invention, the light stabilizer includes a benzotriazole light stabilizer; and the pigment includes a carbon black masterbatch.

[0034] The following experiments illustrate the technical progress of the present invention. The raw materials used are all conventional products in the field, suitable for TPEE, and the specific preparation operations and performance tests are all conventional technologies. The raw materials involved in the examples or comparative examples are as follows: TPEE resin: polyester elastomer material, melt index 20g / 10min, load 2.16kg at 230℃, hardness 55D; brand: Sinopec, TX555, Figure 1 Enlarge the photo for it.

[0035] Antioxidant: Chinox 626 and Chinox 445, mass ratio 1:1.

[0036] Chain extender: Select epoxy chain extender with PBT as carrier, and PBT-4016 is used in the experiment.

[0037] Catalyst: Zinc stearate.

[0038] Modifier: Maleic anhydride grafted hydrogenated styrene-butadiene block copolymer, MEB-7215, MAH grafting ratio 2.1%, hardness 67A.

[0039] FG1901, SEBS grafted with MAH, the grafting ratio of MAH is 1.4%; EBA, DowDuPont, ethylene-butyl acrylate copolymer; EMA, Arkema, ethylene methyl acrylate copolymer.

[0040] Additives: light stabilizer UV-234, benzotriazole light stabilizer; masterbatch AS-5040 Ningbo masterbatch. The weight ratio of the two is 1:3.

[0041] The formula of the high melt stable TPEE system for blow molding in the embodiment and comparative example is shown in Table 1; the processing method is as follows: After all materials are conventionally mixed, they are directly put into twin-screw extrusion for melting processing; the diameter of the twin-screw extruder used is 63 mm, the aspect ratio is 56:1, the processing temperature is 180°C-240°C, the screw speed is 200 rpm, and the feed speed is 250 rpm.

[0042] The testing methods for materials are conventional techniques, which are briefly described as follows: Shore hardness: According to ISO 868, 15s reading, Shore D, requirement is 55±3D; Tensile strength: According to ISO 527, 50mm / min, required to be above 28MPa; Elongation: According to ISO 527, 50mm / min, more than 400% is required; Capillary rheology: According to ISO 11443, temperature 230°C; see the test results of the examples and comparative documents Figure 2 .

[0043] Melt index: According to ISO 1133, temperature 230°C, load 2.16kg, requirement 0.5-1.5g / 10min.

[0044] Table 1 Examples and Comparative Examples Formula, Kg

[0045] Table 2 Performance of materials in Examples and Comparative Examples

[0046] Observe the surface of the test piece with the naked eye and classify the severity of the cracks from severe to mild as cracked, slightly cracked, and no cracks. Only products without cracks meet the requirements. Figure 2 This is a photo of the conventional blow-molded test piece of Example 3. It has no cracks and still has good softness at minus 35°C, meeting the blow molding requirements for large automotive components. Figure 3 This is a photo of the test piece of conventional blow molding sample in Comparative Example 2, which has cracks. Example 8

[0047] According to mass percentage, the formula composition is as follows: Antioxidant 0.3% Chain extender 3% Catalyst 0.3% Modifier 13.5% Additive 2% TPEE resin balance. Example 9

[0048] According to mass percentage, the formula composition is as follows: Antioxidant 0.29% Chain extender 2.8% Catalyst 0.3% Modifier 16% Additive 2% TPEE resin balance. Example 10

[0049] According to mass percentage, the formula composition is as follows: Antioxidant 0.3% Chain extender 2.9% Catalyst 0.29% Modifier 14% Additives 1.8% TPEE resin balance.

[0050] Examples 8 to 10 were prepared by referring to the method of Example 3, and the obtained particles met the blow molding requirements of large automobile components. The present invention avoids the phenomenon of melt fracture caused by TPEE defects. The high melt-stable TPEE system test piece for blow molding prepared by TPEE resin, antioxidant, chain extender, catalyst, modifier and light stabilizer has no melt fracture in appearance, and the product elongation at break is more than 400%, and the Shore hardness is 55±3D, which meets the conventional blow molding requirements of automobile protection.

Claims

1. A high melt stable TPEE system, comprising TPEE resin, antioxidant, chain extender, catalyst, modifier and additive, characterized in that: The modifier includes a maleic anhydride grafted hydrogenated styrene-butadiene block copolymer.

2. The high melt stable TPEE system according to claim 1, characterized in that: The mass ratio of TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent is (60-90): (0.1-0.5): (0.5-5): (0.1-0.5): (8-20): (1-3).

3. The method for preparing the high melt stable TPEE system according to claim 1, characterized in that: The raw materials including TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent are melt-mixed to obtain a high melt stable TPEE system for blow molding.

4. The method for preparing a high melt stable TPEE system according to claim 3, characterized in that: The mass ratio of TPEE resin, antioxidant, chain extender, catalyst, modifier and auxiliary agent is (65-85): (0.1-0.4): (1-4): (0.2-0.4): (10-17): (1-3).

5. The method for preparing a high melt stable TPEE system according to claim 3, characterized in that: The modifier is maleic anhydride grafted hydrogenated styrene-butadiene block copolymer, and the grafting ratio of MAH is 1.8-2.5%.

6. Application of the high melt-stable TPEE system according to claim 1 in solving TPEE blow molding melt fracture.

7. Use of the high melt-stable TPEE system according to claim 1 in the preparation or as a melt-stable TPEE blow molding material.

8. Use of the high melt stable TPEE system according to claim 1 in the preparation of TPEE materials.

9. Use of the high melt stable TPEE system according to claim 1 in the preparation of blow molding TPEE materials.

10. An automobile blow-molded part, prepared by blow molding the high melt stable TPEE system according to claim 1.

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