A functional polyester masterbatch and a method for preparing the same

Abstract

This invention discloses a medical-grade polyester masterbatch and its preparation method, belonging to the field of polyester. The polyester masterbatch includes the preparation of a flow promoter and the mixing of dried polyester chips with the prepared flow promoter and lubricant, followed by co-extrusion granulation to obtain the functional polyester masterbatch. This invention uses a modified flow promoter monomer and lubricant to improve the flowability of the functional polyester material, while also enhancing its demolding ability. The resulting product exhibits good transparency, dimensional stability, and a high product qualification rate.

Description

Technical Field

[0001] This invention relates to the field of polyester, and more specifically to a medical polyester masterbatch and its preparation method. Background Technology

[0002] In recent years, with the continuous development and breakthroughs in medical science and biotechnology, the application of polyethylene terephthalate (PET) in the medical equipment and packaging industries has grown rapidly. It possesses stable chemical properties, is not prone to chemical reactions with substances inside the packaging, and is lightweight, transparent, has excellent barrier properties, is non-toxic, and not easily broken. During the global COVID-19 pandemic in 2020, the demand for high-weight PET blood collection tubes as virus sampling tubes surged. Compared to traditional ordinary glass blood collection tubes, PET tubes offer advantages such as being lightweight and not easily broken, facilitating transportation and storage; having a very low probability of tube wall breakage and sample leakage; being able to be directly autoclaved or incinerated after use without the need for sterilization and reuse; and being low-cost and easy to process.

[0003] Disposable blood collection tubes and other polyester medical containers are products with a high flow-to-length ratio. These products are generally small and thin-walled, and their processing technology differs significantly from that of ordinary PET polyester materials. In injection molding, the polyester material must have good flowability, be easy to demold, have good appearance quality and dimensional stability, and be able to withstand significant static loads. The appearance and manufacturability of the product are key considerations during production. Due to the high flowability of the material, the intrinsic viscosity of the polyester is generally required to be less than 0.70 dL / g. However, because it needs to withstand significant static loads, the intrinsic viscosity should not be too low; a range of 0.60-0.70 dL / g is more suitable.

[0004] Chinese patent CN104448720A discloses a medical-grade modified polyester masterbatch and its preparation method. This invention uses medical polyester chips as a carrier, adding a lubricant, polyethylene wax, to the chips. The polyethylene wax has a number-average molecular weight of 500-10000 and a content of 3%-15% of the polyester weight. This results in easier demolding during injection molding and an increased product qualification rate.

[0005] Chinese patent CN104017338A discloses a polyester slice for manufacturing vacuum blood collection tubes and its preparation method. This patent uses 0.1%-5% stearate (octadecanoic acid) and 0.1%-1% polyethylene wax added to the polyester slice, giving it advantages such as high fluidity, high stability, and rapid demolding.

[0006] Chinese patent CN105860038A discloses a novel production process for medical slides. This process involves adding a mixed solution of stearate and ethylene glycol to a PET esterification system, then adding polyethylene wax to the melt pipeline at the final shrinkage reactor outlet for granulation. The aim is to improve production efficiency and increase product qualification rate.

[0007] In addition, Chinese patent CN106589857A discloses a polyester chip masterbatch for blood collection tubes, its preparation method, and its application. This invention utilizes rheology modifiers such as polyester polyol, stearate, lignite acid and its derivatives, polyethylene glycol, and rheology modifier accelerator organosilicon resin to improve the melt flowability of polyester chips for blood collection tubes.

[0008] Existing patents mainly involve adding stearates, lignite acid, polyethylene glycol, polyester polyols, silicone resins, and polyethylene waxes to medical polyester carriers. However, these flow promoters have problems such as small molecular weight, unstable properties, poor high-temperature resistance, and easy increase of the haze of polyester materials. Summary of the Invention

[0009] The purpose of this invention is to solve the problems of insufficient material fluidity, difficulty in demolding, product eccentricity, flow marks, and low product qualification rate in the existing medical polyester preparation process, and to propose a medical polyester functional masterbatch and its preparation method.

[0010] The objective of this invention can be achieved through the following technical solutions:

[0011] A method for preparing a functional polyester masterbatch, the method comprising the following steps:

[0012] (1) Preparation of flow promoter: using fatty alcohol and tricarboxylic acid as raw materials, esterification reaction is carried out under acidic catalyst conditions to obtain flow promoter;

[0013] (2) Mix the dried polyester chips with the flow promoter and lubricant prepared in step (1), and then perform co-extrusion granulation to obtain functional polyester masterbatch.

[0014] In the technical solution of the present invention: the fatty alcohol mentioned in step (1) is a C16-C24 fatty alcohol.

[0015] In some preferred technical solutions: the fatty alcohol mentioned in step (1) is at least one of octadecyl alcohol, hexadecyl alcohol, tetradecyl alcohol, C16-18 alcohol and C20-22 alcohol.

[0016] In the technical solution of this invention: the tricarboxylic acid in step (1) is trimellitic anhydride, phosphoric acid or citric acid.

[0017] In the technical solution of the present invention: the molar ratio of fatty alcohol and tricarboxylic acid in step (1) is 1 to 8:1.

[0018] In some preferred technical solutions, the molar ratio of fatty alcohols to tricarboxylic acids is 2 to 5:1.

[0019] In the technical solution of this invention: the catalyst mentioned in step (1) is concentrated sulfuric acid.

[0020] In the technical solution of the present invention: the lubricant mentioned in step (2) is pentaerythritol stearate PETS or silicone oil.

[0021] In the technical solution of this invention: the amount of flow promoter monomer added in step (2) is 0.5%-10% of the weight of polyester chips.

[0022] In the technical solution of this invention: the amount of lubricant added in step (2) is 0.1%-0.6% of the weight of the polyester chips.

[0023] In the technical solution of this invention: the amount of catalyst used in step (1) is 0.01%-0.1% of the raw materials.

[0024] In the technical solution of this invention: the esterification reaction conditions are heating to reflux temperature and esterification reaction time of 30 min to 2 h.

[0025] The above-mentioned functional polyester masterbatch is prepared by the following method:

[0026] (1) Preparation of flow promoter: Fatty alcohol and tricarboxylic acid are used as raw materials and esterification reaction is carried out in the presence of catalyst to obtain flow promoter;

[0027] (2) Mix the dried polyester chips with the flow promoter and lubricant prepared in step (1), and then perform co-extrusion granulation to obtain functional polyester masterbatch.

[0028] The innovation of this invention lies in the following: It utilizes fatty alcohols (C16-C24) and tricarboxylic acids (which can be trimellitic anhydride, phosphoric acid, or citric acid, preferably trimellitic anhydride) to prepare tricarboxylic acid fatty alcohol esters or fatty alcohols (C16-C24) and their derivatives. The resulting monomers have a large molecular weight, making them less susceptible to extraction from the system during the twin-screw blending, granulation, and degassing stage. They are also stable and heat-resistant. The monomers contain three long fatty alcohol molecular chains, forming a flow-promoting group that improves the flowability and demolding ability of medical polyester materials. Adding this monomer to medical polyester easily produces a two-phase structure, causing the molecular chains to rotate into various complex spatial conformations and rotational isomers. Furthermore, the chains are intertwined, making it difficult to obtain complete crystals upon melt cooling. This results in a crystalline structure with a certain amount of amorphous regions, significantly reducing material haze, resulting in products with good transparency, dimensional stability, and a high product qualification rate.

[0029] The beneficial effects of this invention are:

[0030] This invention employs a modified flow promoter monomer and lubricant to improve the flowability of functional polyester materials, while simultaneously enhancing demolding ability. The resulting products exhibit good transparency, dimensional stability, and a high product qualification rate. This invention solves the problems of existing flow promoters, such as low molecular weight, easy extraction from the granulation and degassing system during twin-screw mixing, unstable properties, poor high-temperature resistance, and increased haze affecting the appearance of polyester materials. Adding this medical-grade polyester masterbatch to conventional polyester base materials significantly improves flowability and demolding ability, increases melt index by over 30%, and reduces haze by 20%-50%. It also solves problems such as blood collection tube eccentricity and surface flow marks, achieving a product qualification rate as high as 99.5%. This aligns with current industrial trends towards green, environmentally friendly, energy-saving, and emission-reducing products, and possesses significant market potential. Detailed Implementation

[0031] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto:

[0032] Comparative Example 1:

[0033] Commercially available medical polyester chips have an intrinsic viscosity of 0.63 dL / g.

[0034] Comparative Example 2:

[0035] Using a Nanjing Jieya Machinery HT-36 high-torque co-rotating twin-screw extruder, medical-grade polyester chips with an intrinsic viscosity of 0.70 dL / g were vacuum-dried at 160℃ for 5 hours and then blended with lubricant silicone oil for extrusion granulation. The lubricant silicone oil was added via a peristaltic pump through the liquid feed inlet at a rate of 0.6% of the weight of the medical-grade polyester chips. The main feed inlet was water-cooled for temperature control. The screw temperatures for each section were set as follows: T1 220℃, T2 255℃, T3-T14 265℃. The screw load was 25 kg / h, and the screw speed was set to 180 rpm. The materials were uniformly mixed in the screw and extruded into strips through a 4-hole die. After cooling in a water bath, the strips were granulated using a pelletizer to obtain medical-grade polyester masterbatch chips with an intrinsic viscosity of 0.65 dL / g. The masterbatch was added to the medical-grade polyester base material at a ratio of 8% wt. The relevant index data of the final medical-grade polyester product are shown in the table below.

[0036] Example 1:

[0037] (1) Octadecanol and citric acid were mixed in a molar ratio of 3:1 and heated to 155°C under the condition that the amount of concentrated sulfuric acid catalyst was 0.02% of the weight of the reactants, and refluxed for 1.5 h to obtain the flow promoter monomer octadecyl citrate.

[0038] (2) Using Nanjing Jieya Machinery's HT-36 high-torque co-rotating twin-screw extruder, medical polyester chips with an intrinsic viscosity of 0.70 dL / g were vacuum dried at 160℃ for 5 hours, and then thoroughly mixed with the flow promoter monomer octadecyl citrate and the lubricant pentaerythritol stearate PETS. The mixture was then co-extruded and granulated. The amount of octadecyl citrate added was 3% of the weight of the medical polyester chips, and the amount of pentaerythritol stearate added was 0.6% of the weight of the medical polyester chips. The main feed port was water-cooled and temperature-controlled. The screw temperatures for each section were set as follows: T1 was 220℃, T2 was 255℃, and T3-T14 were 265℃. The screw load was 25 kg / h, and the screw speed was set to 180 rpm. The materials were mixed evenly in the screw and extruded into strips through a 4-hole die. After cooling in a water tank, the strips were granulated by a pelletizer to finally obtain medical polyester masterbatch chips with an intrinsic viscosity of 0.56 dL / g. The masterbatch was added to the medical polyester base material at a ratio of 5% wt, and the relevant index data of the final medical polyester product are shown in the table below.

[0039] Example 2:

[0040] (1) Hexadecyl alcohol and trimellitic anhydride were mixed in a molar ratio of 3:1 and heated to 120°C under the condition that the amount of concentrated sulfuric acid catalyst was 0.05% of the weight of the reactants, and refluxed for 1.2 h to obtain the flow promoter monomer hexadecyl trimellitic acid ester.

[0041] (2) Using Nanjing Jieya Machinery's HT-36 high-torque co-rotating twin-screw extruder, medical polyester chips with an intrinsic viscosity of 0.80 dL / g were vacuum dried at 160℃ for 5 hours and then thoroughly mixed with the flow promoter monomer hexadecyl trimellitate. The lubricant silicone oil was added through the liquid feed port using a peristaltic pump. The mixture was then extruded and granulated. The amount of hexadecyl trimellitate added was 10% of the weight of the medical polyester chips, and the amount of silicone oil added was 0.1% of the weight of the medical polyester chips. The main feed port was water-cooled and temperature-controlled. The screw temperatures for each section were set as follows: T1: 220℃, T2: 255℃, T3-T14: 265℃. The screw load was 30 kg / h, and the screw speed was set to 180 rpm. The materials were mixed evenly in the screw and extruded into strips through a 4-hole die. After cooling in a water tank, the strips were granulated by a pelletizer to obtain medical polyester masterbatch chips with an intrinsic viscosity of 0.61 dL / g. The masterbatch was added to the medical polyester base material at a ratio of 3% wt, and the relevant index data of the final medical polyester product are shown in the table below.

[0042] Example 3:

[0043] (1) Tetracosyl ester of trimellitic anhydride was prepared by mixing tetracosyl ester and trimellitic anhydride in a molar ratio of 3:1 and heating to 120°C under the condition that the amount of concentrated sulfuric acid catalyst was 0.01% of the weight of the reactants and refluxing for 2 hours.

[0044] (2) Using Nanjing Jieya Machinery's HT-36 high-torque co-rotating twin-screw extruder, medical polyester chips with an intrinsic viscosity of 0.80 dL / g were vacuum dried at 160℃ for 5 hours and then thoroughly mixed with the flow promoter monomer trimellitic acid tetracosyl ester. The lubricant silicone oil was added through the liquid feed port using a peristaltic pump. The mixture was then extruded and granulated. The amount of trimellitic acid tetracosyl ester added was 4% of the weight of the medical polyester chips, and the amount of silicone oil added was 0.3% of the weight of the medical polyester chips. The main feed port was water-cooled and temperature-controlled. The screw temperatures for each section were set as follows: T1 was 220℃, T2 was 255℃, and T3-T14 were 265℃. The screw load was 35 kg / h, and the screw speed was set to 180 rpm. The materials were mixed evenly in the screw and extruded into strips through a 4-hole die. After cooling in a water tank, the strips were granulated by a pelletizer to finally obtain medical polyester masterbatch chips with an intrinsic viscosity of 0.48 dL / g. The masterbatch was added to the medical polyester base material at a ratio of 4% wt, and the relevant index data of the final medical polyester product are shown in the table below.

[0045] Example 4:

[0046] (1) C16-18 alcohol and phosphoric acid were mixed in a molar ratio of 3:1, heated to 90°C under the condition that the amount of concentrated sulfuric acid catalyst was 0.1% of the weight of the reactants, and refluxed for 30 min to obtain the flow promoter monomer hexadecanoic acid phosphate C16-18P.

[0047] (2) Using Nanjing Jieya Machinery's HT-36 high-torque co-rotating twin-screw extruder, medical polyester chips with an intrinsic viscosity of 0.80 dL / g were vacuum-dried at 160℃ for 5 hours, and then thoroughly mixed with the flow promoter monomer cetearyl phosphate C16-18P and the lubricant pentaerythritol stearate PETS. The mixture was then co-extruded and granulated. The amount of cetearyl phosphate C16-18P added was 5% of the weight of the medical polyester chips, and the amount of pentaerythritol stearate... The ester addition was 0.1% of the weight of the medical polyester chips. The main feed inlet used water cooling for temperature control. The screw temperatures for each section were set as follows: T1 220℃, T2 255℃, T3-T14 265℃. The screw load was 30 kg / h, and the screw speed was set to 180 rpm. The material was uniformly mixed in the screw and extruded into strips through a 4-hole die. After cooling in a water bath, the strips were granulated using a pelletizer to obtain medical polyester masterbatch chips. The intrinsic viscosity was measured to be 0.63 dL / g. The masterbatch was added to the medical polyester base material at a ratio of 2% wt. The relevant index data of the final medical polyester product are shown in the table below.

[0048] Example 5:

[0049] (1) C20-22 alcohol and phosphoric acid were mixed in a molar ratio of 3:1 and heated to 80°C under the condition that the amount of concentrated sulfuric acid catalyst was 0.06% of the weight of the reactants, and refluxed for 1 h to obtain the flow promoter monomer phosphate ester C20-22P.

[0050] (2) Using Nanjing Jieya Machinery's HT-36 high-torque co-rotating twin-screw extruder, medical polyester chips with an intrinsic viscosity of 0.75 dL / g were vacuum-dried at 160℃ for 5 hours, and then thoroughly mixed with the flow promoter monomer phosphate ester C20-22P and the lubricant silicone oil. The silicone oil was added through the liquid feed inlet using a peristaltic pump. The mixture was then extruded and granulated. The amount of C20-22P added was 0.5% of the weight of the medical polyester chips, and the amount of silicone oil added was 0.6% of the weight of the medical polyester chips. The main feed inlet was water-cooled for temperature control. The screw temperatures for each section were set as follows: T1: 220℃, T2: 255℃, T3-T14: 265℃. The screw load was 25 kg / h, and the screw speed was set to 180 rpm. The materials were mixed evenly in the screw. The material is extruded into strips using a die head, cooled in a water bath, and then granulated using a pelletizer to obtain medical-grade polyester masterbatch chips with an intrinsic viscosity of 0.61 dL / g. The masterbatch is added to the medical-grade polyester base material at a ratio of 5% wt. The relevant index data of the final medical-grade polyester product are shown in the table below.

[0051] Example 6:

[0052] Using a Nanjing Jieya Machinery HT-36 high-torque co-rotating twin-screw extruder, medical polyester chips with an intrinsic viscosity of 0.80 dL / g were vacuum dried at 160℃ for 5 hours, then thoroughly mixed with a flow promoter (cetadecaoctadecanol) and a lubricant (silicone oil). The silicone oil was added via a peristaltic pump through the liquid feed inlet for co-extrusion granulation. The cetadecaoctadecanol addition was 6% of the weight of the medical polyester chips, and the silicone oil addition was 0.5% of the weight of the medical polyester chips. The main feed inlet was water-cooled for temperature control. The screw temperatures for each section were set as follows: T1: 220℃, T2: 255℃, T3-T14: 265℃. The screw load was 30 kg / h, and the screw speed was set to 180 rpm. The materials were mixed evenly in the screw and extruded into strips through a 4-hole die. After cooling in a water bath, the strips were granulated by a pelletizer to obtain medical polyester masterbatch chips with an intrinsic viscosity of 0.59 dL / g. The masterbatch was added to the medical polyester base material at a ratio of 3% wt, and the relevant index data of the final medical polyester product are shown in the table below.

[0053]

[0054] Note: The relevant index data were tested in accordance with the polyester testing standard (GB / T14190-2009) and the disposable human venous blood sample collection container standard (YY0314-2007). The melt index test conditions were 280℃ and 2.16Kg.

Claims

1. A method for preparing a functional polyester masterbatch, characterized in that, The method includes the following steps: (1) Preparation of flow promoter: using fatty alcohol and tricarboxylic acid as raw materials, esterification reaction is carried out under acidic catalyst conditions to obtain flow promoter; the fatty alcohol is at least one of octadecyl alcohol, hexadecyl alcohol, and tetracosyl alcohol, and the tricarboxylic acid is trimellitic anhydride, phosphoric acid or citric acid; the molar ratio of fatty alcohol to tricarboxylic acid is 1~8:

1. (2) Mix the dried polyester chips with the flow promoter and lubricant prepared in step (1), and then perform co-extrusion granulation to obtain functional polyester masterbatch; the amount of flow promoter added is 0.5%-10% of the weight of polyester chips; the lubricant is pentaerythritol stearate PETS or silicone oil.

2. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of fatty alcohols and tricarboxylic acids is 2~5:

1.

3. The preparation method according to claim 1, characterized in that: The catalyst mentioned in step (1) is concentrated sulfuric acid.

4. The preparation method according to claim 1, characterized in that: In step (2), the amount of lubricant added is 0.1%-0.6% of the weight of the polyester chips.

5. The preparation method according to claim 1, characterized in that: In step (1), the amount of catalyst used is 0.01%-0.1% of the raw material, and the esterification reaction time is 30 min-2 h.

6. A functional polyester masterbatch, characterized in that, It is prepared by the method described in any one of claims 1 to 5.

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