Aluminum carboxylate composite nucleating agent for improving mechanical properties of polypropylene

Abstract

The invention provides an aluminum carboxylate composite nucleating agent for improving the mechanical property of polypropylene. The aluminum carboxylate composite nucleating agent is prepared from the following components in percentage by mass: 0.5 to 99.5 percent of an aluminum carboxylate nucleating agent and 0.5 to 99.5 percent of an ethylene bis stearamide dispersing agent, the addition amount of the aluminum carboxylate composite nucleating agent accounts for 0.05-0.3% of the mass of the polypropylene. The aluminum carboxylate nucleating agent which is widely applied at present, good in nucleating performance and easy to prepare is compounded by adopting a specific dispersing agent according to a specific ratio, and the compounded composite nucleating agent is better in stability and dispersity. Due to the synergistic effect after compounding, the rigidity and toughness of polypropylene can be better balanced, and the original high rigidity can be kept while the impact strength can be greatly improved.

Description

Technical Field

[0001] The present invention relates to a nucleating agent used in the technical field of polypropylene, in particular to a carboxylate aluminum salt composite nucleating agent used for improving the mechanical properties of polypropylene. Background Art

[0002] Polypropylene is a semi-crystalline thermoplastic polymer made from propylene monomer via the polyaddition reaction. It is typically a white, waxy solid, non-toxic, odorless, transparent, and lightweight. Due to its excellent mechanical properties, low cost, safety, non-toxicity, low relative density, good chemical resistance, and excellent molding and processing properties, it is widely used in the chemical, light, and chemical fiber industries.

[0003] Polypropylene is a semi-crystalline resin. The addition of nucleating agents as crystal nuclei will accelerate the crystallization rate of polypropylene and increase the crystallinity, thereby improving the mechanical properties of polypropylene.

[0004] Homogeneous nucleation of polypropylene is relatively slow. Adding a nucleating agent promotes heterogeneous nucleation, allowing the polypropylene molecular chains to align and crystallize around the nucleating agent. This increases the temperature required for polypropylene crystallization, thereby reducing the processing cycle. Nucleating agents based on aluminum carboxylates are widely used due to their excellent nucleation properties and simple preparation. However, these nucleating agents exhibit poor stability and dispersibility, failing to meet the requirements for high-performance polypropylene. Summary of the Invention

[0005] The purpose of the present invention is to provide a carboxylate aluminum salt composite nucleating agent for improving the mechanical properties of polypropylene.

[0006] In order to achieve the above object, the technical solution adopted in the present invention is as follows:

[0007] The present invention provides a carboxylate aluminum salt composite nucleating agent for improving the mechanical properties of polypropylene, characterized in that the carboxylate aluminum salt composite nucleating agent is made of the following components in percentage by mass: 0.5-99.5 wt% of the carboxylate aluminum salt nucleating agent and 0.5-99.5 wt% of the ethylene bisstearamide dispersant; the addition amount of the carboxylate aluminum salt composite nucleating agent accounts for 0.1% of the mass of the polypropylene;

[0008] The aluminum carboxylate nucleating agent is selected from the sodium salt, lithium salt, potassium salt, calcium salt, magnesium salt or aluminum salt of at least one of cyclohexanedicarboxylic acid, cyclobutanedicarboxylic acid, cyclopentanedicarboxylic acid and methylhexahydrophthalic acid.

[0009] The dispersant can be selected from at least one of aluminosilicates, alkali metal phosphates, triethylhexyl phosphate, sodium lauryl sulfate, methyl amyl alcohol, cellulose acetate, polyacrylamide, guar gum, and fatty acid polyethylene glycol esters.

[0010] Preferably, the polypropylene is homopolymer polypropylene, copolymer polypropylene or random copolymer polypropylene.

[0011] Preferably, the polypropylene has a dispersibility index of 2-30 and a melt flow index of 1-100 g / 10 min.

[0012] Preferably, the aluminum carboxylate salt composite nucleating agent comprises 80 wt % of di(4-tert-butyl-benzoate)aluminum and 20 wt % of ethylene bis-stearyl dispersant.

[0013] The composite nucleating agent of the present invention can also be mixed with other substances such as antioxidants, modification aids, fillers, etc. for use.

[0014] Due to the adoption of the above technical solution, the present invention has the following advantages and gain effects:

[0015] This invention utilizes a widely used, easily prepared aluminum carboxylate nucleating agent with excellent nucleating properties. The compounded nucleating agent is compounded with a specific dispersant in a specific ratio. The resulting composite nucleating agent exhibits enhanced stability and dispersibility. This synergistic effect creates a better balance between the rigidity and toughness of polypropylene, significantly improving impact strength while maintaining the original high rigidity. Compared to existing composite nucleating agents, the tensile strength is increased by 5-10%, and the flexural modulus is increased by 3-25%. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention, but the present invention is not limited thereto.

[0017] The polypropylene used in the following examples has a dispersibility index of 2-30 and a melt flow index of 1-100 g / 10 min.

[0018] Example 1

[0019] A carboxylate aluminum salt composite nucleating agent for improving the mechanical properties of polypropylene is prepared from the following components in percentage by mass: 85 wt% aluminum di(4-tert-butylbenzoate) and 15 wt% ethylene bisstearamide dispersant; the amount of the carboxylate aluminum salt composite nucleating agent added is 0.1% of the mass of the polypropylene; the polypropylene used is Sinopec's T30S to illustrate the experimental results, but the polypropylene is not limited to T30S.

[0020] Following the method described in Example 1 for controlling the mechanical properties of polypropylene, a composite nucleating agent containing an aluminum carboxylate salt and an additive was added to a T30S product at a ratio of 8.5:1.5. This composite nucleating agent was then added to the product to control its properties. When the composite nucleating agent was used to control the mechanical properties of polypropylene, the tensile strength increased by 7.16% and the flexural modulus increased by 19% compared to the blank polypropylene. Compared to pure aluminum carboxylate salt nucleating agent, the tensile strength of polypropylene increased by 1% and the flexural modulus increased by 2.1%.

[0021] Example 2

[0022] A carboxylate aluminum salt composite nucleating agent for improving the mechanical properties of polypropylene is prepared from the following components in percentage by weight: 80 wt% aluminum di(4-tert-butylbenzoate) and 20 wt% ethylene bisstearamide dispersant. The aluminum salt composite nucleating agent is added in an amount of 0.1% by weight of the polypropylene. The polypropylene used is Sinopec's T30S for illustrating the experimental results, but the polypropylene is not limited to T30S.

[0023] Following the method described in Example 1 for controlling the mechanical properties of polypropylene, a composite nucleating agent containing an aluminum carboxylate salt and an additive was added to a T30S mixture at a ratio of 8:2. This composite nucleating agent was then added to the mixture to control its properties. When the composite nucleating agent was used to control the mechanical properties of polypropylene, the tensile strength increased by 7.59% and the flexural modulus increased by 20.7% compared to the blank polypropylene. Compared to pure aluminum carboxylate salt nucleating agent, the tensile strength of polypropylene increased by 1% and the flexural modulus increased by 3.75%.

[0024] Example 3

[0025] A carboxylate aluminum salt composite nucleating agent for improving the mechanical properties of polypropylene is prepared from the following components in percentage by weight: 75% by weight of aluminum di(4-tert-butylbenzoate) and 25% by weight of an ethylene bisstearamide dispersant. The aluminum salt composite nucleating agent is added in an amount of 0.1% by weight of the polypropylene. The polypropylene used is Sinopec's T30S for illustrating the experimental results, but the polypropylene is not limited to T30S.

[0026] Following the method described in Example 1 for controlling the mechanical properties of polypropylene, a composite nucleating agent containing an aluminum carboxylate salt and an additive was added to a T30S mixture at a ratio of 7.5:2.5. This composite nucleating agent was then added to the mixture to control its properties. When the composite nucleating agent was used to control the mechanical properties of polypropylene, the tensile strength increased by 6.84% and the flexural modulus increased by 19.4% compared to the blank polypropylene. Compared to pure aluminum carboxylate salt nucleating agent, the tensile strength of polypropylene increased by 0.2% and the flexural modulus increased by 2.45%.

[0027] Example 4

[0028] A carboxylate aluminum salt composite nucleating agent for improving the mechanical properties of polypropylene is prepared from the following components in percentage by weight: 70% by weight of aluminum di(4-tert-butylbenzoate) and 30% by weight of an ethylene bisstearamide dispersant. The aluminum carboxylate salt composite nucleating agent is added in an amount of 0.1% by weight of the polypropylene. The polypropylene used is Sinopec's T30S for illustrating the experimental results, but the polypropylene is not limited to T30S.

[0029] Following the method described in Example 1 for controlling the mechanical properties of polypropylene, a composite nucleating agent containing an aluminum carboxylate salt and an additive was added to a T30S mixture at a ratio of 7:3. This composite nucleating agent was then added to the mixture to control its properties. When the composite nucleating agent was used to control the mechanical properties of polypropylene, the tensile strength increased by 6.52% and the flexural modulus increased by 19.24% compared to the blank polypropylene. Compared to the pure aluminum carboxylate salt nucleating agent, the tensile strength of polypropylene was essentially the same, and the flexural modulus increased by 2.29%.

[0030] Example 5

[0031] A carboxylate aluminum salt composite nucleating agent for improving the mechanical properties of polypropylene is prepared from the following components in percentage by weight: 65 wt% aluminum di(4-tert-butylbenzoate) and 35 wt% ethylene bisstearamide dispersant. The aluminum salt composite nucleating agent is added in an amount of 0.1% by weight of the polypropylene. The polypropylene used is Sinopec's T30S for illustrating the experimental results, but the polypropylene is not limited to T30S.

[0032] Following the method described in Example 1 for controlling the mechanical properties of polypropylene, a composite nucleating agent containing an aluminum carboxylate salt and an additive was added to a T30S product at a ratio of 6.5:3.5. This composite nucleating agent was then added to the product to control its properties. When the composite nucleating agent was used to control the mechanical properties of polypropylene, the tensile strength increased by 6.62% and the flexural modulus increased by 17.85% compared to the blank polypropylene. Compared to the pure aluminum carboxylate salt nucleating agent, the tensile strength of polypropylene remained essentially the same, while the flexural modulus increased by 1%.

[0033] Test data of Examples 1-5

[0034]

[0035] The above comparison revealed that the method for controlling the mechanical properties of polypropylene using a composite nucleating agent containing aluminum carboxylate and an additive showed significantly superior results when a specific ethylene bisstearamide dispersant was selected and the optimal composite ratio was 8:2. The tensile strength increased by 7.59% and the flexural modulus increased by 20.7% compared to the blank polypropylene. Compared to pure aluminum carboxylate nucleating agent, the tensile strength of polypropylene increased by 1% and the flexural modulus increased by 3.75%.

[0036] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above technical content without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A carboxylate aluminum salt composite nucleating agent for improving the mechanical properties of polypropylene, characterized in that , is made of the following components in percentage by weight: 0.5-99.5 wt% of a carboxylate aluminum salt nucleating agent and 0.5-99.5 wt% of an ethylene bisstearamide dispersant; the amount of the carboxylate aluminum salt composite nucleating agent added accounts for 0.05-0.3% of the mass of the polypropylene; The aluminum carboxylate nucleating agent is selected from the sodium salt, lithium salt, potassium salt, calcium salt, magnesium salt and aluminum salt of at least one of cyclohexanedicarboxylic acid, cyclobutanedicarboxylic acid, cyclopentanedicarboxylic acid and methylhexahydrophthalic acid.

2. The aluminum carboxylate salt composite nucleating agent for improving the mechanical properties of polypropylene according to claim 1, characterized in that: The added amount of the composite nucleating agent accounts for 0.05-0.3% of the mass of the polypropylene.

3. The aluminum carboxylate salt composite nucleating agent for improving the mechanical properties of polypropylene according to claim 1, characterized in that: The polypropylene is homopolymer polypropylene, copolymer polypropylene or random copolymer polypropylene.

4. The aluminum carboxylate salt composite nucleating agent for improving the mechanical properties of polypropylene according to claim 1, characterized in that: The polypropylene dispersion index is 2-30, and the melt flow index is 1~100g / 10min.

5. The aluminum carboxylate salt composite nucleating agent for improving the mechanical properties of polypropylene according to claim 1, characterized in that: The aluminum carboxylate salt composite nucleating agent comprises 80 wt % of di(4-tert-butyl-benzoic acid)aluminum and 20 wt % of an ethylene bisstearamide dispersant.

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