High-shear stripping-resistant PET (Polyethylene Terephthalate) foam material and preparation method thereof

Abstract

The invention relates to a high-shear stripping-resistant PET (polyethylene terephthalate) foam material and a preparation method thereof, and the PET foam material is prepared from the following components in parts by weight: 60 to 90 parts of PET slices, 10 to 30 parts of bio-based nylon, 0.1 to 0.5 part of anhydride chain extender, 0.1 to 1 part of tetrafunctional glycidyl ester type epoxy macromolecule, 0.1 to 0.5 part of oxazoline chain extender and 0.1 to 3 parts of nucleating agent. And 0.1-1 part of an antioxidant. The shear performance and peel strength of the PET foaming material can be effectively improved, the PET foaming material can reach the level close to balsa wood, the proportion of the PET foaming material in the blade is further increased, and the purpose of reducing the proportion of the balsa wood is achieved.

Description

Technical Field

[0001] The invention relates to the field of PET foam materials, and in particular to a high-shear peeling-resistant PET foam material and a preparation method thereof. Background Art

[0002] At present, the domestic blade design relies heavily on balsa wood, accounting for 38%, while PET only accounts for 28%. 85% of foreign blades are already PET foam core materials, and balsa wood accounts for only 15%. At present, my country's wind turbine blades use balsa wood heavily dependent on imports, and the key raw materials for the development of the blade industry are subject to others. If PET foam materials are used to replace balsa wood, the main issues are shear performance and peel strength. The industrial production of high shear and peel-resistant PET foam materials will be achieved, thereby promoting the sustainable and healthy development of my country's wind power industry and promoting the long-term, stable and sustainable use of energy resources, which is in line with the country's requirements for building a resource-saving and environmentally friendly society, and helping my country achieve its dual carbon goals.

[0003] Patent 201910674069.5 discloses a chain extender for aromatic polyester microporous foaming materials. The invention mixes graphene oxide and epoxy resin in a ratio of 1:3 to 1:9 by mass, and then adds a promoter accounting for 1 to 1.5% of the total mass of graphene oxide and epoxy resin, and finally obtains a foamable aromatic polyester with a characteristic viscosity of 1.0 to 1.2 dL / g. The graphene oxide used in the invention is expensive and not suitable for industrial production; the bisphenol A epoxy resin or bisphenol F epoxy resin used has only two epoxy groups, which can only play a linear chain extension role, but cannot effectively form a branched structure, and cannot significantly improve the mechanical properties of the foaming core material to meet the blade design indicators.

[0004] Patent 201710445333.9 discloses a blended modified aromatic polyester microporous foam material and a preparation method thereof, wherein the main components include 60-95 parts by weight of aromatic polyester, 5-40 parts by weight of polyamide, 0.1-3 parts by weight of multifunctional epoxy chain extender, 0-2 parts by weight of cell nucleating agent, and 0.1-3 parts by weight of antioxidant. The obtained product has high characteristic viscosity, high apparent cell density, and a closed cell rate of not less than 80%. The multifunctional epoxy chain extender used in the invention is BASF's ADR series chain extender. Due to its large number of epoxy groups and excessive reaction activity, it is impossible to stably control the production process to achieve industrial production when it is applied in industry. Summary of the invention

[0005] The purpose of the present invention is to provide a high shear and peeling resistant PET foam material and a preparation method thereof, so as to improve the shear performance and peeling strength of the PET foam material to a level close to that of balsa wood, thereby reducing the amount of balsa wood used in blades.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a high-shear peeling-resistant PET foam material, the components of which include 60-90 parts of PET chips, 10-30 parts of bio-based nylon, 0.1-0.5 parts of anhydride chain extenders, 0.1-1 parts of tetrafunctional glycidyl ester type epoxy macromolecules, 0.1-0.5 parts of oxazoline chain extenders, 0.1-3 parts of nucleating agents, and 0.1-1 parts of antioxidants in terms of weight.

[0007] Preferably, the bio-based nylon is one or a mixture of more than one including but not limited to PA56, PA510, and PA513.

[0008] Preferably, the anhydride chain extender is one of PMDA and BTDA.

[0009] Preferably, the tetrafunctional glycidyl ester type epoxy macromolecule is TGDDM.

[0010] Preferably, the oxazoline chain extender is one of PBO or BOZ.

[0011] Preferably, the nucleating agent is one or a mixture of talc, calcium carbonate, Surlyn resin, and AClyn resin.

[0012] Preferably, the antioxidant is one of antioxidant 1098, antioxidant 1330, antioxidant 3114, antioxidant 626, and antioxidant 686, or a mixture of more thereof.

[0013] Preferably, the physical foaming agent is one or a mixture of carbon dioxide, nitrogen, alkane, and freon.

[0014] A method for preparing a high-shear peeling-resistant PET foam material comprises the following steps:

[0015] Step (1), adding PET chips, bio-based nylon, anhydride chain extender, tetrafunctional glycidyl ester epoxy macromolecule, oxazoline chain extender, nucleating agent, and antioxidant into a twin-screw extruder by weight loss weighing;

[0016] Step (2), adding 0.5-3 wt % of a physical foaming agent into the twin-screw extruder;

[0017] Step (3), after the twin-screw extruder is melt-mixed and uniformly mixed, the mixture is transported to a single-screw extruder and extruded through a shaping die;

[0018] Step (4), manufacturing the foamed board into corresponding structural core material according to the blade shell process.

[0019] The beneficial effects of the present invention are as follows: 1. Compared with petroleum-based nylon, 45% of the bio-based nylon is synthesized from green, renewable and environmentally friendly materials, with a smaller carbon footprint in the life cycle, which helps to promote the achievement of dual carbon goals.

[0020] 2. Bio-based nylon has a unique even-odd structure, and the N—H and C=O in its macromolecular chain are in a dislocated state; its even-odd hydrogen bond structure has high thermal stability at high temperatures. At the same time, the hydrogen bonds in bio-based nylon present a dislocated configuration. When the hydrogen bonds of bio-based nylon dissociate at high temperatures, it will slide toward the macromolecular chain, and the original unsaturated hydrogen bonds will form new high-strength hydrogen bonds. At the same time, it has low water absorption, which reduces moisture degradation when blended with PET materials, and greatly improves the shear strength and shear modulus of the foaming material.

[0021] 3. The PET molecular chain has terminal carboxyl and terminal hydroxyl groups. Anhydride chain extenders can react with terminal hydroxyl groups. Due to the molecular activity, the number of functional groups participating in the reaction of anhydride chain extenders is about 3, and a certain branching structure is formed while extending the chain. Oxazoline chain extenders contain two carbon-nitrogen five-membered heterocycles, which preferentially react with terminal carboxyl groups to play a role in chain extension. The tetrafunctional glycidyl ester epoxy macromolecule contains four symmetrical epoxy groups, which can react with the terminal carboxyl groups on the PET molecular chain to increase its molecular weight, form a dendritic spatial network structure, and greatly improve the material's anti-destruction performance.

[0022] 4. The epoxy group of the tetrafunctional glycidyl ester epoxy macromolecule can also react with the terminal amino group on the bio-based nylon molecular chain, combining the bio-based nylon and PET with chemical bonds, providing sufficient interface connection strength, ensuring the transfer of loads, and improving the peel strength of the foaming material.

[0023] 5. Through the blending modification of bio-based nylon and the chemical modification of combined chain extenders, the two are combined to achieve high shear performance and peeling resistance of PET foam materials, reaching the overall performance level of balsa wood, thereby achieving the use of PET foam materials in wind turbine blades to reach more than 85%.

[0024] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of a tetrafunctional glycidyl ester type epoxy macromolecule.

[0026] Figure 2 It is a schematic diagram of the structure of bisphenol A epoxy resin.

[0027] Figure 3 It is a schematic diagram of the structure of the ADR series chain extenders. DETAILED DESCRIPTION

[0028] like Figures 1 to 3 shown.

[0029] Embodiment 1, a high shear peeling resistant PET foam material, whose components include 60-90 parts of PET chips, 10-30 parts of bio-based nylon, 0.1-0.5 parts of anhydride chain extender, 0.1-1 parts of tetrafunctional glycidyl ester type epoxy macromolecule, 0.1-0.5 parts of oxazoline chain extender, 0.1-3 parts of nucleating agent, and 0.1-1 parts of antioxidant in terms of weight.

[0030] Example 2, a high shear and peel-resistant PET foam material, whose components, by weight, include 90 parts of PET chips, 10 parts of bio-based nylon, 0.2 parts of anhydride chain extender, 0.6 parts of tetrafunctional glycidyl ester type epoxy macromolecules, 0.3 parts of oxazoline chain extender, 2 parts of nucleating agents, and 0.5 parts of antioxidants.

[0031] Example 3, a high shear and peel-resistant PET foam material, whose components, by weight, include 80 parts of PET chips, 20 parts of bio-based nylon, 0.3 parts of anhydride chain extender, 0.5 parts of tetrafunctional glycidyl ester type epoxy macromolecules, 0.5 parts of oxazoline chain extender, 2 parts of nucleating agents, and 0.5 parts of antioxidants.

[0032] Example 4, a high shear and peel-resistant PET foam material, whose components, by weight, include 70 parts of PET chips, 30 parts of bio-based nylon, 0.5 parts of anhydride chain extender, 1 part of a tetrafunctional glycidyl ester type epoxy macromolecule, 0.2 parts of an oxazoline chain extender, 2 parts of a nucleating agent, and 0.5 parts of an antioxidant.

[0033] Example 5, based on the high shear peeling resistant PET foam material described in Examples 1-3, the tetrafunctional glycidyl ester type epoxy macromolecule is TGDDM.

[0034] The bio-based nylon includes but is not limited to one or a mixture of PA56, PA510, and PA513.

[0035] The acid anhydride chain extender is one of PMDA and BTDA.

[0036] The oxazoline chain extender is one of PBO and BOZ.

[0037] The nucleating agent is one or a mixture of talcum powder, calcium carbonate, Surlyn resin and AClyn resin.

[0038] The antioxidant is one of antioxidant 1098, antioxidant 1330, antioxidant 3114, antioxidant 626, and antioxidant 686, or a mixture of multiple thereof.

[0039] The physical foaming agent is one or a mixture of carbon dioxide, nitrogen, alkane and freon.

[0040] Embodiment 6, a method for preparing a high shear peeling resistant PET foam material based on Embodiments 1-4, comprising the following steps:

[0041] Step (1), adding PET chips, bio-based nylon, anhydride chain extender, tetrafunctional glycidyl ester epoxy macromolecule, oxazoline chain extender, nucleating agent, and antioxidant into a twin-screw extruder by weight loss weighing;

[0042] Step (2), adding 0.5-3 wt % of a physical foaming agent into the twin-screw extruder;

[0043] Step (3), after the twin-screw extruder is melt-mixed and uniformly mixed, the mixture is transported to a single-screw extruder and extruded through a shaping die;

[0044] Step (4), manufacturing the foamed board into corresponding structural core material according to the blade shell process.

[0045] The physical and mechanical properties of the structural core materials are tested according to relevant standards. Density is measured according to ISO 845, shear strength and shear modulus are measured according to ISO 1922 or ASTM C273, and peel strength is measured according to ASTM D1781, as shown in the table below.

[0046] PET foam material performance test data sheet

[0047] experiment Balsa Conventional PET Example 2 Example 3 Example 4 density 310 320 315 300 310 Shear strength / MPa 3 1.45 1.9 2.3 2.1 Shear modulus / MPa 155 125 145 150 158 Peel strength 65 45 68 63 72

[0048] From the data in the above table, it can be seen that by adding bio-based nylon and combined chain extenders, the shear strength, shear performance and peel strength of the foamed material are greatly improved compared with conventional PET foam; compared with balsa wood, although there is a certain gap in shear strength, it is also greatly improved compared with conventional PET foam, and at the same time, the shear modulus and peel strength are also closer. The high shear and peel-resistant PET foam material disclosed in the present invention can already meet the design indicators of a part of the blade area, thereby achieving the purpose of increasing the use of PET materials and reducing the degree of dependence on balsa wood.

[0049] In the description of the present invention, it is to be understood that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "one", "one" and "one" used herein are also intended to include plural forms. It should also be understood that the terms "include" and / or "comprise" used herein specify the existence of stated features, integers, steps, operations, units and / or components, without excluding the existence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.

[0050] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A high shear and peel-resistant PET foam material, characterized in that: The components thereof include, by weight, 60-90 parts of PET chips, 10-30 parts of bio-based nylon, 0.1-0.5 parts of anhydride chain extenders, 0.1-1 parts of tetrafunctional glycidyl ester epoxy macromolecules, 0.1-0.5 parts of oxazoline chain extenders, 0.1-3 parts of nucleating agents, and 0.1-1 parts of antioxidants.

2. The high shear peeling resistant PET foam material according to claim 1, characterized in that: The tetrafunctional glycidyl ester type epoxy macromolecule is TGDDM.

3. The high shear peeling resistant PET foam material according to claim 1, characterized in that: The bio-based nylon is one or a mixture of PA56, PA510 and PA513.

4. The high shear peeling resistant PET foam material according to claim 1, characterized in that: The acid anhydride chain extender is one of PMDA and BTDA.

5. The high shear peeling resistant PET foam material according to claim 1, characterized in that: The oxazoline chain extender is one of PBO and BOZ.

6. The high shear peeling resistant PET foam material according to claim 1, characterized in that: The nucleating agent is one or a mixture of talcum powder, calcium carbonate, Surlyn resin and AClyn resin.

7. The high shear peeling resistant PET foam material according to claim 1, characterized in that: The antioxidant is one of antioxidant 1098, antioxidant 1330, antioxidant 3114, antioxidant 626, and antioxidant 686, or a mixture of multiple thereof.

8. The high shear peeling resistant PET foam material according to any one of claims 1 to 7, characterized in that: The physical foaming agent is one or a mixture of carbon dioxide, nitrogen, alkane and freon.

9. A method for preparing a high shear peeling resistant PET foam material, characterized in that: The steps include: Step (1), feeding PET slices, bio-based nylon, anhydride chain extender, tetrafunctional glycidyl ester epoxy macromolecule, oxazoline chain extender, nucleating agent, and antioxidant into a twin-screw extruder by weight ratio through a loss-in-weight scale; Step (2), adding 0.5-3 wt % of a physical foaming agent into the twin-screw extruder; Step (3), after the twin-screw extruder is melt-mixed and uniformly mixed, the mixture is transported to a single-screw extruder and extruded through a shaping die; Step (4), manufacturing the foamed board into corresponding structural core material according to the blade shell process.

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