Quickly crystallized toughened PET (Polyethylene Terephthalate) material as well as preparation method and application thereof

Abstract

The invention relates to a rapidly crystallized toughened PET (Polyethylene Terephthalate) material as well as a preparation method and application thereof. The PET material comprises the following substances in parts by weight: 73-95 parts of PET resin, 1-10 parts of a composite nucleating agent, 0.5-2 parts of an antioxidant, 2-10 parts of a polyamide polymer toughening agent and 1-5 parts of a crystallization accelerant, wherein the composite nucleating agent is formed by compounding metal carboxylate and inorganic mineral, the metal carboxylate is used as an organic nucleating agent, and the inorganic mineral is used as an inorganic nucleating agent. The method of combining the composite nucleating agent and the accelerant is adopted, so that the problem of degradation caused by introduction of the organic nucleating agent is avoided while the crystallization speed and crystallinity of the material are improved, and the mechanical property of the material is improved. The dosage of additives in the blending formula is small, and the material is high in crystallization rate and crystallization rate under the condition of rapid cooling. Under the condition that a large number of inorganic fibers are not added, compared with a pure PET material, the PET material has the advantages that the crystallization capacity of the material is improved, the impact strength of the material is obviously improved, and other mechanical properties are not obviously reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular materials, in particular to a fast-crystallizing toughened PET material, a preparation method and application thereof. BACKGROUND

[0002] PET is a common polyester material, which has excellent mechanical properties, heat resistance, electrical properties and the like. However, due to its slow crystallization speed, it is usually used as fibers, films and bottle pieces, and is rarely used in the field of engineering plastics mainly using injection molding process. This is because the two methylene groups contributed by ethylene glycol residues in the molecular structure of PET make the chain spacing between benzene rings in the PET molecular chain structure short, and the rigidity of the structure is large. When cooling, the high rigidity of PET is not conducive to the regular arrangement of chain segments and the growth of crystal grains, and therefore, when PET is used as an engineering plastic for injection molding, high mold temperature and long holding time are required, and sometimes annealing treatment is also required to achieve the ideal crystallization state.

[0003] The problem to be solved for using PET as an engineering plastic is how to improve the crystallization speed of PET. The current mature technology is to add a crystallization nucleating agent and a crystallization promoter. The crystallization nucleating agent is an essential additive for providing heterogeneous nucleation points for PET and improving the crystallization speed and refining the crystal grains of PET. Commonly used nucleating agents are mainly divided into two categories. One is inorganic nucleating agents, such as silicon dioxide and talc powder. The other is organic nucleating agents, which are usually carboxylate salts. However, a single inorganic nucleating agent needs to be added in a high proportion to have a good nucleation effect. However, the inorganic nucleating agent has poor dispersion effect and is prone to agglomeration. Although the organic nucleating agent has a small addition amount and good effect on improving the crystallization ability of PET, the currently used organic nucleating agent can cause the breakage of PET molecular chains and reduce the impact strength of the material.

[0004] Patent CN202410049460.7 discloses a kind of fast crystallization PET resin composition for engineering plastics and its preparation method and application.The main components of the PET resin composition include PET, nucleating agent and hydrogel by weight parts, wherein the nucleating agent is metal salt nucleating agent.The PET resin composition of the application improves the crystallization ability of PET, effectively improves the impact strength of the material.But the addition of a large amount of hydrogel leads to the decline of material temperature resistance and the bending strength cannot meet the use as engineering material, and then needs to fill more than 10 parts of glass fiber as reinforcement, which increases the production and processing cost of the material.Patent CN202310520520.4 discloses a kind of fast crystallization modified PET composition and its preparation method and application, and the nucleating agent is a mixture of organic ion type metal sodium salt nucleating agent and surface carbonyl modified magnesium hydroxide, which has high crystallization temperature, narrow crystallization half peak width and high crystallization rate.But the nucleating agent reacts with PET molecular chain at high temperature to form chemical nucleation, which easily causes PET molecular chain degradation, especially in the process of making PET molecular weight decrease, which affects the mechanical strength.

[0005] Therefore, it is of wide application prospect to develop a kind of easy-to-process fast-crystallization toughened PET material. SUMMARY

[0006] As introduced in the background, in the scheme of improving the crystallization speed of PET, a single inorganic nucleating agent needs to be added in a high proportion to have a good nucleation effect, but the inorganic nucleating agent has poor dispersion effect and is easy to agglomerate, and the organic nucleating agent has a small amount of addition and a good effect of improving the crystallization ability of PET, but the currently used organic nucleating agent can cause PET molecular chain degradation and reduce the impact strength of the material, and other schemes, such as adding hydrogel, can cause the decline of material temperature resistance and the bending strength cannot meet the use as engineering material.

[0007] In view of the deficiencies in the prior art, the present application provides a kind of fast crystallization toughened PET material and its preparation method and application, and the application adopts the method of composite nucleating agent and accelerator, so as to improve the crystallization speed and crystallinity of the material, avoid the degradation problem caused by introducing organic nucleating agent, improve the mechanical properties of the material, meet the application scene of injection molding, so that the material meets the requirements of industrial design freedom, and can be applied in more industrial and consumer product fields.

[0008] The object of the present application can be achieved by the following technical solutions:

[0009] The present application first provides a kind of fast crystallization toughened PET material, and the PET material includes the following substances by weight parts:

[0010] PET resin (polyethylene terephthalate resin) 73-95 parts,

[0011] Composite nucleating agent 1-10 parts,

[0012] Antioxidant 0.5-2 parts,

[0013] Polyamide polymer toughening agent 2-10 parts,

[0014] Crystallization promoter 1-5 parts;

[0015] The composite nucleating agent is compounded by a metal carboxylate and an inorganic mineral, the metal carboxylate as an organic nucleating agent and the inorganic mineral as an inorganic nucleating agent.

[0016] In an embodiment of the present application, the weight ratio of the metal carboxylate to the inorganic mineral in the composite nucleating agent is 2-1:1.

[0017] In an embodiment of the present application, the organic carboxylate is selected from one or a combination of sodium benzoate, potassium benzoate, aluminum p-t-butylbenzoate, sodium pyridine-2-carboxylate, sodium citrate, potassium sorbate, potassium citrate, zinc stearate or calcium stearate, preferably the organic carboxylate is selected from one or a combination of sodium citrate or potassium sorbate.

[0018] In an embodiment of the present application, the inorganic mineral is selected from one or a combination of silicon dioxide, calcium carbonate, talc, kaolin or montmorillonite, preferably the inorganic mineral is selected from one or a combination of silicon dioxide or calcium carbonate.

[0019] In an embodiment of the present application, the particle size of the inorganic mineral is between 0.1-10 μm.

[0020] In an embodiment of the present application, the intrinsic viscosity of the PET resin (polyethylene terephthalate resin) is 0.5-1.2 dL / g, preferably 0.7-1.1 dL / g.

[0021] In an embodiment of the present application, the polyamide polymer toughening agent is selected from one or a combination of PA6, PA66, PA56, PA1010 or PA1012, preferably the polyamide polymer toughening agent is selected from one or a combination of PA6, PA56 or PA1010.

[0022] In an embodiment of the present application, the intrinsic viscosity of the polyamide polymer toughening agent is 0.9-3 dL / g.

[0023] In one embodiment of the present application, the crystallization promoter is a two-armed or multi-armed polyethylene glycol derivative, preferably, the crystallization promoter is polyethylene glycol diglycidyl ether with a molecular weight of 400-10000.

[0024] In one embodiment of the present application, the antioxidant is selected from one or a combination of several of tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite or tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester.

[0025] The present application further provides a method for preparing the fast-crystallized and toughened PET material, comprising the following steps:

[0026] The components are weighed by weight parts, and then melt-blended by a single-screw or double-screw extruder after mixing, to obtain the PET material.

[0027] In one embodiment of the present application, the screw plasticizing temperature is 240-265℃, which can be adjusted by the skilled in the art according to the specific components and processing efficiency.

[0028] In one embodiment of the present application, the inorganic mineral is surface-treated before use, and the surface treatment method is as follows: a 5wt% silane coupling agent KH560 aqueous solution is prepared, the pH value is adjusted to 4-5 by dilute hydrochloric acid, and then stirred at room temperature for 20-30min, then the solution is added dropwise into the inorganic mineral powder, the solution is added in an amount of 50-150wt% of the weight of the inorganic mineral powder, and then stirred at high speed (500-1000rpm) for 10-20min, and then dried at 80-105℃ for 0.5-2.0h to obtain the surface-treated inorganic mineral powder.

[0029] The present application further provides the application of the fast-crystallized and toughened PET material, which is used to prepare injection-molding products, including but not limited to cosmetic packaging materials.

[0030] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0031] The present application uses the method of combining nucleating agent and promoter, thereby improving the crystallization speed and crystallinity of the material, avoiding the degradation problem caused by the introduction of organic nucleating agent, and improving the mechanical properties of the material. The additive amount of the blending formula is small, the material has a fast crystallization rate and high crystallization rate under the condition of rapid cooling.

[0032] Without adding a large amount of inorganic fibers, the PET material of the present application improves the crystallization ability of the material, and the impact strength of the material is significantly improved compared with the pure PET material, and other mechanical properties do not decrease significantly.

[0033] The prepared toughened PET material meets the application scenarios of injection molding processing, so that the material meets the requirements of industrial design freedom and can be applied in more industrial and consumer product fields. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 For the DSC curves of the PET materials of Comparative Example 1 and Comparative Example 4, the abscissa is temperature (Temperature) in ℃, and the ordinate is heat flow (Heat Flow) in mW / mg.

[0035] Figure 2 For the DSC curves of the PET materials of Example 1 and Example 6, the abscissa is temperature (Temperature) in ℃, and the ordinate is heat flow (Heat Flow) in mW / mg.

[0036] Figure 3 For the physical photos of the PET materials of Comparative Example 1 and Example 1. DETAILED DESCRIPTION

[0037] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0038] The sources of raw materials in the embodiments and comparative examples in the present application are shown in Table 1 below.

[0039] Table 1: Raw material description in the embodiments and comparative examples

[0040]

[0041]

[0042] Raw material description:

[0043] Prepare a 5wt% silane coupling agent KH560 aqueous solution, adjust the pH value to between 4-5 with dilute hydrochloric acid, stir at room temperature for 25 min, then add this solution to the inorganic nucleating agent powder, the addition amount of the solution is 10-20wt% of the weight of the inorganic powder, and then stir at a high speed of 800-1000 rpm for 5-10 min, and then dry at 95℃ for 1 hour. The surface-treated inorganic nucleating agent powder is obtained.

[0044] PET resin, organic nucleating agent, inorganic nucleating agent, toughening agent, antioxidant need to be pre-dried before proportioning, drying temperature is between 80-120℃, ensure the water content of the material is less than 0.1%.

[0045] In the following examples, the performance test method is described as follows:

[0046] Crystallization property: measured by DSC (differential scanning calorimeter), the crystallization temperature refers to the temperature of the material in the cooling process from amorphous melt state to crystal. The difference between crystallization temperature and melting temperature, the size of the crystallization speed of the material in the cooling process, the smaller the temperature difference, the easier the crystallization; on the other hand, the area of crystallization peak is related to the crystallinity, the larger the crystallization peak area per unit mass, the higher the crystallinity. The crystallization peak temperature under non-isothermal crystallization conditions is measured by DSC, and the temperature program of DSC is set as follows: the sample is heated to 280℃ at a rate of 30℃ / min, and then cooled to 30℃ at a rate of 30℃ / min.

[0047] Notch impact strength: the notch impact strength of the material is measured according to the standard of American standard ASTM D256, the test temperature is 23℃, and the test sample is formed by injection molding according to the proportion of the material, the processing temperature is 240-265℃, the mold temperature is 60℃, and the injection pressure is 60-65bar.

[0048] Demoulding cooling time: the demoulding cooling time refers to the time required for the material to change from melt state to solid state in the injection molding process, which reflects the actual cooling time of the material in actual processing. The standard tensile mold of ASTM specification is used for material injection test, and the demoulding time of different materials under the same injection temperature (260-280℃) and mold temperature (60℃) is compared.

[0049] The present scheme is further illustrated by specific examples as follows.

[0050] The material composition of examples 1-8 is shown in table 2, the material composition of examples 9-12 is shown in table 3, and the material composition of comparative examples 1-5 is shown in table 4, in tables 2, 3 and 4, the unit is weight part.

[0051] Table 2 material composition of examples 1-8

[0052]

[0053] Table 3 material composition of examples 9-12

[0054]

[0055]

[0056] Table 4 Material composition of Comparative Examples 1-5

[0057]

[0058] The technical effects of the materials of Examples 1-12 and Comparative Examples 1-5 are shown in Table 5.

[0059] Table 5 Technical effects of the materials of Examples 1-12 and Comparative Examples 1-5

[0060]

[0061] Figure 1 For the DSC curves of the PET materials of Comparative Example 1 and Comparative Example 4, the crystallization peak temperature of the material using a single inorganic nucleating agent (Comparative Example 4, Modified PET in the figure) is 195°C, while the crystallization peak temperature of the pure material PET (Comparative Example 1 of the material without any modification, Pure PET in the figure) is 143°C, and the crystallization peak temperatures of the other composite formula nucleating agent materials (Examples 1-12 and Comparative Examples 2, 5) measured at a cooling rate of 30°C / min are all above 190°C (and in Comparative Example 3, although the composite formula nucleating agent is added, no crystallization promoter polyglycol diglycidyl ether is added, so the crystallization peak temperature is slightly lower than 190), which is much higher than the crystallization peak temperature of the pure material of 143°C, the demolding time is reduced from 80s to less than 30s, and the area of the crystallization peak is also much larger than that of the unmodified sample (Comparative Example 1). Therefore, using the formula of the examples, the crystallization ability of the material during rapid cooling is obviously improved, which can meet the requirements of the product in actual injection molding production.

[0062] From the notched impact strength results of Examples 2-4 and Comparative Examples 1, 2 and 5, it can be seen that the notched impact of the rapidly crystallizing PET material without toughening with PA6 will decrease significantly, from 16.2J / m of the pure material to 6.2J / m. When PA6 is used for toughening, the problem of the decrease in the notched impact performance of the material is obviously improved. When the PA6 addition amount is 6%, the notched impact strength of Example 3 is 36J / m, which is twice that of the pure material (Comparative Example 1), and the toughness and notched impact strength of the material are obviously improved in the remaining examples using nylon as the toughening agent.

[0063] Comparing the crystallization peak temperatures of Example 1 and Comparative Example 3, the crystallization peak temperature of Example 1 measured at a cooling rate of 30°C / min is 211°C, and the crystallization peak temperature of Comparative Example 3 is 183°C. Therefore, the addition of polyglycol diglycidyl ether as a crystallization promoter is obviously helpful to improve the crystallization ability of the material under rapid cooling.

[0064] Figure 2 For the DSC curves of the PET materials of Example 1 and Example 6, it can be seen that different raw material PET and the amount of nucleating agent affect the crystallization peak temperature of the obtained PET material. The crystallization peak temperature of Example 1 measured at a cooling rate of 30°C / min is 211°C (Modified-1), and the crystallization peak temperature of Example 6 is 208°C (Modified-2). Figure 2 Figure 2

[0065] Figure 3 For the comparison of the physical photos of Comparative Example 1 and Example 1, the physical color of the pure PET material of Comparative Example 1 is whiter, and the physical color of the prepared PET material of Example 1 after adding the nucleating agent, the toughening agent, the crystallization promoter and the antioxidant is yellower.

[0066] The above experimental results prove that the present technology can improve the crystallization ability of the material and greatly improve the toughness of the material to meet the application of polyester in the field of injection molding products.

[0067] The above description of the embodiments is to facilitate the understanding and use of the present application by those skilled in the art. Those skilled in the art can obviously make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the present application without departing from the scope of the present application should be within the scope of protection of the present application.​​

Claims

1. A rapidly crystallized, toughened PET material, characterized in that, The PET material comprises the following ingredients by weight: PET resin 73-95 parts, Composite nucleating agent 1-10 parts, Antioxidant 0.5-2 parts, Polyamide polymer toughening agent 2-10 parts, Crystallization promoter 1-5 parts; The composite nucleating agent is compounded from a metal carboxylate and an inorganic mineral, the metal carboxylate serving as an organic nucleating agent and the inorganic mineral serving as an inorganic nucleating agent.

2. A rapidly crystallized, toughened PET material according to claim 1, characterized in that, The weight ratio of the metal carboxylate to the inorganic mineral in the composite nucleating agent is 2-1:

1.

3. A rapidly crystallized, toughened PET material according to claim 1, characterized in that, The organic carboxylate is selected from one or a combination of several of sodium benzoate, potassium benzoate, aluminum p-t-butylbenzoate, sodium pyridine-2-carboxylate, sodium citrate, potassium sorbate, potassium citrate, zinc stearate or calcium stearate.

4. A rapidly crystallized, toughened PET material according to claim 1, characterized in that, The inorganic mineral is selected from one or a combination of several of silicon dioxide, calcium carbonate, talc, kaolin or montmorillonite; the particle size of the inorganic mineral is between 0.1 and 10 μm.

5. A rapidly crystallized, toughened PET material according to claim 1, characterized in that, The intrinsic viscosity of the PET resin is 0.5-1.2 dL / g.

6. A rapidly crystallized, toughened PET material according to claim 1, characterized in that, The polyamide polymer toughening agent is selected from one or a combination of several of PA6, PA66, PA56, PA1010 or PA1012; the intrinsic viscosity of the polyamide polymer toughening agent is 0.9-3 dL / g.

7. A rapidly crystallized, toughened PET material according to claim 1, characterized in that, The crystallization promoter is polyethylene glycol diglycidyl ether with a molecular weight of between 400 and 10,000.

8. A rapidly crystallized, toughened PET material according to claim 1, characterized in that, The antioxidant is selected from one or a combination of several of tris(2,4-di-t-butylphenyl) phosphite, bis(2,4-di-t-butylphenyl) pentaerythritol diphosphate or tetrakis[β-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester.

9. Process for the production of the rapidly crystallizing, toughened PET material according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: The components are weighed and mixed, and then melt blended in a single-screw or twin-screw extruder to obtain the PET material; The plasticizing temperature of the screw is 240-265°C; The inorganic mineral is surface treated before use, and the surface treatment method is as follows: a 5 wt% silane coupling agent KH560 aqueous solution is prepared, the pH value is adjusted to between 4 and 5 with dilute hydrochloric acid, and the solution is stirred at room temperature for 20-30 min, then the solution is added dropwise to the inorganic mineral powder, the amount of the solution added is 50-150 wt% of the weight of the inorganic mineral powder, and the mixture is stirred at a speed of 500-1000 rpm for 10-20 min, and then dried at 80-105°C for 0.5-2.0 hours to obtain the surface-treated inorganic mineral powder.

10. Use of the rapidly crystallized, toughened PET material according to any one of claims 1 to 8, characterized in that The rapidly crystallized and toughened PET material is used to make injection molding products.

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