Polymer polyester chemical fiber and preparation method thereof

Abstract

The invention relates to the technical field of chemical fiber materials, in particular to a macromolecular polyester chemical fiber which is prepared from the following components in parts by weight: 60-70 parts of polyester polyol; 25 to 30 parts of toluene diisocynate; 3 to 8 parts of an epoxidized SBS (Styrene Butadiene Styrene) toughening agent; 1-2 parts of silicone oil; 0.5 to 1.5 parts of a tertiary amine catalyst; 0.3 to 0.8 part of an active amino modifier; and 0.5 to 1.2 parts of an antioxidant. The invention also discloses a preparation method of the composition. By adding the epoxidized SBS toughening agent, the toughness of the high-molecular polyester chemical fiber is improved, and the application range is widened; a composite catalyst containing primary amine and tertiary amine is used for adjusting the reaction rate, enhancing the flexibility of a molecular chain and improving the elasticity and processability of the fiber; the phenol antioxidant is added to inhibit high-temperature oxidative degradation and maintain the performance of the fiber; a fluorine-containing or silane oleophobic layer of 5-10 microns is coated after post-treatment, so that the surface energy is reduced, the oil resistance and the practicability are improved, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of chemical fiber materials technology, and in particular to a high molecular weight polyester chemical fiber and its preparation method. Background Technology

[0002] Polyester fiber is a common chemical fiber material widely used in textiles, industry, and many other fields. As industries increasingly demand higher performance from chemical fibers, traditional polyester fibers are finding it increasingly difficult to meet certain requirements. For example, in specific industrial environments or high-end textile applications, chemical fibers need to possess better toughness, thermal stability, oxidation resistance, and oil resistance.

[0003] In the preparation of traditional polyester fibers, only basic polyester polyols and isocyanates are typically used for the reaction. This simple system results in relatively poor toughness and aging resistance of the fibers. They are prone to breakage under external force and are susceptible to oxidative degradation at high temperatures, leading to a decline in performance. Furthermore, their oil resistance cannot meet the requirements of some special scenarios, such as industrial environments with a lot of oil. In addition, in terms of synthesis process, the stirring and curing conditions of traditional methods are not precise enough, resulting in uneven and insufficient reaction, which ultimately affects the overall performance and quality of the fibers. Summary of the Invention

[0004] To address the shortcomings of the aforementioned technologies, this invention provides a high-molecular-weight polyester fiber and its preparation method, the resulting polyester fiber exhibiting excellent properties.

[0005] This invention discloses a high-molecular-weight polyester fiber, prepared from the following components by weight fraction:

[0006] Polyester polyol: 60-70 parts

[0007] Toluene diisocyanate: 25-30 parts

[0008] Epoxidized SBS toughening agent: 3-8 parts,

[0009] Silicone oil: 1-2 parts

[0010] Tertiary amine catalyst: 0.5-1.5 parts,

[0011] Active amine modifier: 0.3-0.8 parts,

[0012] Antioxidant: 0.5-1.2 parts.

[0013] The epoxidized SBS toughening agent is synthesized by catalytic phase transfer catalyst of phosphotungsten peroxide heteropolyacid. Its molecular structure contains block polymeric active amine groups, which form a chemical cross-linking network with polyester polyol.

[0014] The active amine modifier is a composite catalyst containing primary and tertiary amines, used to regulate the reaction rate and enhance the flexibility of the molecular chain.

[0015] The antioxidant is phenol or its derivative, preferably added in an amount of 0.6-0.8 parts, to inhibit oxidative degradation during high-temperature reactions.

[0016] A method for preparing a high-molecular-weight polyester fiber includes the following steps:

[0017] Step 1, raw material pretreatment: Heat the polyester polyol to 35-45℃, and keep the toluene diisocyanate, silicone oil, tertiary amine catalyst and antioxidant at 20-25℃ respectively.

[0018] Step 2, Mixing reaction: Polyester polyol and toluene diisocyanate are injected into the reactor in proportion and reacted. Then, epoxidized SBS toughening agent, silicone oil, tertiary amine catalyst, active amine modifier and antioxidant are added to react and form a homogeneous mixture.

[0019] Step 3, continuous curing: Inject the mixture into the mold cavity and carry out a continuous reaction at 80-100℃ for 10-15 minutes;

[0020] Step 4, Post-processing: After cooling, cut into a fibrous structure and coat the surface with an oleophobic layer to enhance oil resistance.

[0021] The synthesis steps of the epoxidized SBS toughening agent include:

[0022] (1) Using hydrogen peroxide as the oxygen source, SBS epoxidation was catalyzed by phosphotungsten peroxide heteropolyacid phase transfer catalyst.

[0023] (2) Block polymer active amine groups are introduced into the SBS backbone through grafting reaction to form cross-linking points.

[0024] The oleophobic layer is achieved by spraying a fluorinated compound or a silane coupling agent, with a thickness of 5-10 μm, reducing surface energy to resist oil penetration.

[0025] The polymer polyester fiber and its preparation method obtained by this invention have the following beneficial effects:

[0026] 1. By adding epoxidized SBS toughening agent, which is synthesized by catalysis of phosphotungsten peroxide heteropoly acid phase transfer catalyst, its molecular structure contains block polymer active amine groups, which can form a chemical cross-linking network with polyester polyol, significantly improving the toughness of polymer polyester fiber, making it less prone to breakage when subjected to external force, thus broadening its application range and making it suitable for industrial fields and special textiles with high toughness requirements.

[0027] 2. Using a composite catalyst containing primary and tertiary amines as an active amine modifier can precisely regulate the reaction rate, ensure that the reaction is complete and uniform, and improve product quality. At the same time, this modifier can also enhance the flexibility of the molecular chain, making the fiber more elastic and processable, and improving the performance of the product.

[0028] 3. Adding phenol or its derivatives as antioxidants can effectively inhibit oxidative degradation in high-temperature reactions, maintain the strength, color and chemical stability of fibers, extend the service life of products, reduce production costs, and enable products to maintain good performance in high-temperature environments.

[0029] 4. In the post-processing stage of the preparation process, an oleophobic layer is coated on the fiber surface. This oleophobic layer is achieved by spraying a fluorinated compound or a silane coupling agent, with a thickness of 5-10 μm. This reduces the surface energy, effectively resists oil penetration, and makes the fiber less susceptible to contamination and erosion in oily environments. This improves the oil resistance and usability of the product, facilitates cleaning and maintenance, and extends the product's service life. Detailed Implementation

[0030] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with preferred embodiments, is provided below.

[0031] Example 1:

[0032] This invention discloses a high-molecular-weight polyester fiber, prepared from the following components by weight fraction:

[0033] Polyester polyol: 65 parts;

[0034] Toluene diisocyanate: 28 parts;

[0035] Epoxidized SBS toughening agent: 5 parts;

[0036] Silicone oil: 1.5 parts;

[0037] Tertiary amine catalyst: 1.0 part;

[0038] Active amine modifier: 0.5 parts;

[0039] Oleophobic coating: fluorinated compounds;

[0040] Antioxidant: 0.7 parts of phenol derivative;

[0041] A method for preparing high molecular weight polyester fiber:

[0042] Pretreatment: The polyester polyol is placed in an environment of 40°C for drying and dehydration treatment. The purpose is to remove any moisture that may be present, to avoid moisture affecting subsequent reactions, to prevent adverse phenomena such as foaming, and to ensure the quality and performance stability of the product.

[0043] Mixing: The pretreated polyester polyol and toluene diisocyanate are mixed and reacted at 25°C. This temperature condition helps control the reaction rate, allowing the two to react and form a preliminary polymer structure. The uniformity of the reaction directly affects the performance of the final product.

[0044] Toughening: Add epoxidized SBS toughening agent to the mixed system and set the stirring speed to 5500 r / min. The toughening agent improves the toughness and impact resistance of the product. A higher stirring speed allows it to be more evenly dispersed in the system, ensuring the consistency of the toughening effect. Among them, the epoxidized SBS toughening agent undergoes a ring-opening reaction with the carboxyl groups of the polyester polyol, and the active amine groups (-NH2) simultaneously crosslink with the isocyanate to form a three-dimensional network structure, which improves the elongation at break and inhibits stress cracking.

[0045] Stabilization: Silicone oil, tertiary amine catalyst, and active amine modifier are added to the system after the mixed reaction. Silicone oil can adjust the surface tension of the system, giving the product better smoothness and gloss; the catalyst can accelerate the reaction process; the active amine modifier helps improve certain properties of the polymer, such as improving adhesion. These additives work together to regulate the flowability of the system, preparing it for subsequent molding; among them, the active amine modifier, primary amine (-NH2) accelerates the -NCO / -OH reaction, and tertiary amine catalyzes the side reaction; flexible segments are interspersed between hard segments, lowering the glass transition temperature and improving low-temperature toughness;

[0046] Molding: The treated system described above is poured and then cured at 90°C for 12 minutes. The curing process is a crucial step for further cross-linking of the polymer to form a stable structure; the control of time and temperature significantly affects the product's hardness, strength, and other properties. Finally, a fluorinated oleophobic layer with a thickness of 8 μm is coated onto the cured surface. This oleophobic layer imparts oil and water resistance to the product. The fluorinated oleophobic layer features oriented -CF groups forming a low surface energy, while the silane coupling agent enhances the coating / substrate adhesion. The contact angle is larger than that of edible oil, and the volume expansion rate is reduced.

[0047] Performance test results:

[0048] Tensile strength: 45 MPa;

[0049] Elongation at break: 320%;

[0050] Oil resistance (ASTM D471): Volume expansion rate < 5%;

[0051] Thermal stability (TGA): 5% weight loss temperature > 320℃.

[0052] Example 2:

[0053] This invention discloses a high-molecular-weight polyester fiber, the difference in its formulation and preparation method compared to Example 1 being:

[0054] The amount of epoxidized SBS toughening agent was increased to 8 parts;

[0055] The oleophobic layer was replaced with a silane coupling agent with a thickness of 10 μm;

[0056] The molding and curing conditions were: 95℃ for 10 minutes.

[0057] The stirring speed was increased to 6000 r / min after adding the epoxidized SBS toughening agent to enhance the dispersion uniformity.

[0058] The performance test results differ in the following ways:

[0059] The elongation at break was significantly increased to 380% (enhanced toughness);

[0060] Oil resistance is optimized to a volume expansion rate of <3%.

[0061] Example 3:

[0062] This invention discloses a high-molecular-weight polyester fiber, the difference in its formulation and preparation method compared to Example 1 being:

[0063] The tertiary amine catalyst was increased to 1.5 parts;

[0064] The amount of epoxidized SBS toughening agent was reduced to 3 parts;

[0065] The oleophobic coating thickness was reduced to 5 μm;

[0066] The molding and curing conditions were: 80℃ for 15 minutes.

[0067] The performance test results differ in the following ways:

[0068] Tensile strength increased to 48 MPa (rigidity enhanced);

[0069] Thermal stability reaches 5%, weight loss temperature > 325℃.

[0070] Comparative Example 1:

[0071] The difference between this solution and Example 1 is as follows:

[0072] 70 parts of polyester polyol;

[0073] 25 parts of toluene diisocyanate;

[0074] 1.5 parts silicone oil;

[0075] 1.0 part of tertiary amine catalyst;

[0076] 0.5 parts of active amine modifier;

[0077] Oleophobic coating: Fluorine-containing compound, 8μm thick;

[0078] Antioxidant: Phenol derivative, 0.7 parts;

[0079] The process steps and parameters in the preparation method remain unchanged.

[0080] The performance was tested, and the defects were:

[0081] The elongation at break plummeted to 180% (a decrease of 43.75%);

[0082] Oil resistance deteriorates to a volume expansion rate >10%.

[0083] Comparative Example 2:

[0084] The difference between this solution and Example 1 is as follows:

[0085] Non-active amine modifier;

[0086] The process steps and parameters in the preparation method remain unchanged.

[0087] The performance was tested, and the defects were:

[0088] Oil resistance decreased to a volume expansion rate >8%;

[0089] Thermal stability decreases to 5% with a weight loss temperature >305℃.

[0090]

[0091] in conclusion:

[0092] The role of epoxidized SBS toughening agent

[0093] Comparative Example 1 Verification: The lack of toughening agent led to a 55% decrease in toughness (180%→320%) and a deterioration in oil resistance (>10%→<5%).

[0094] Example 2 verification: When the toughening agent content was increased to 8 parts, the elongation at break increased to 380%, and the toughness was significantly enhanced.

[0095] The role of active amine modifiers

[0096] Comparative Example 2 verification: without modifier, oil resistance decreased by 40% (>8% → <5%), indicating that modifier is crucial for the formation of oleophobic layer.

[0097] Process parameter optimization

[0098] Example 3: When the amount of tertiary amine catalyst was increased to 1.5 parts, the tensile strength was increased to 48 MPa, but the elongation at break was reduced, reflecting a balance between rigidity and flexibility.

[0099] Oleophobic coating design

[0100] Fluorinated compounds (Examples 1 and 3) exhibit superior oil resistance (<3% vs. <4% for silane coupling agents);

[0101] Performance testing:

[0102] Tensile strength and elongation at break

[0103] Testing methods: Tensile strength and elongation at break are generally obtained through tensile testing. During the test, an axial tensile force is applied to the specimen until it breaks, and the stress and elongation of the specimen during the tensile process are measured at the same time.

[0104] Test principle: Tensile strength refers to the maximum stress that a material can withstand during the stretching process, which reflects the material's ability to resist tensile failure. Elongation at break refers to the percentage of the material's elongation at break relative to its original length, reflecting the material's toughness and deformation capacity.

[0105] Oil resistance

[0106] Test method: The test was conducted using the ASTM D471 standard method, which specifies the test method for determining changes in rubber properties using the liquid immersion method.

[0107] Test principle: After immersing the sample in a specific oil for a certain period of time, the volume change of the sample is measured. Oil resistance is expressed by the volume expansion rate. The smaller the volume expansion rate, the better the oil resistance of the material.

[0108] thermal stability

[0109] Test method: Thermogravimetric analysis (TGA) was used to test thermal stability in this paper. During the test, the sample was placed in a heating furnace with precise temperature control and heated in a certain atmosphere (such as nitrogen or air) at a certain heating rate. At the same time, the change of mass of the sample with temperature was continuously measured.

[0110] Test principle: Based on the data of sample mass changing with temperature, a thermogravimetric curve can be plotted. Generally, parameters such as the 5% weight loss temperature can be obtained from the thermogravimetric curve to assess the thermal stability of the material. A higher 5% weight loss temperature indicates greater stability of the material at high temperatures and stronger resistance to thermal decomposition.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simplification, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-molecular-weight polyester fiber, characterized in that, It is prepared from the following components by weight fraction: Polyester polyol: 60-70 parts Toluene diisocyanate: 25-30 parts Epoxidized SBS toughening agent: 3-8 parts, Silicone oil: 1-2 parts Tertiary amine catalyst: 0.5-1.5 parts, Active amine modifier: 0.3-0.8 parts, Antioxidant: 0.5-1.2 parts.

2. The polymer polyester fiber according to claim 1, characterized in that, The epoxidized SBS toughening agent is synthesized by catalytic synthesis using a phosphotungsten peroxide heteropolyacid phase transfer catalyst, and its molecular structure contains block polymeric active amine groups.

3. The polymer polyester fiber according to claim 1, characterized in that, The active amine modifier is a composite catalyst containing primary and tertiary amines.

4. The polymer polyester fiber according to claim 1, characterized in that, The antioxidant is phenol or its derivative, and the amount added is 0.6-0.8 parts.

5. A method for preparing a polymeric polyester fiber as described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1, raw material pretreatment: Heat the polyester polyol to 35-45℃, and keep the toluene diisocyanate, silicone oil, tertiary amine catalyst and antioxidant at 20-25℃ respectively. Step 2, Mixing reaction: Polyester polyol and toluene diisocyanate are injected into the reactor in proportion and reacted. Then, epoxidized SBS toughening agent, silicone oil, tertiary amine catalyst, active amine modifier and antioxidant are added to react and form a homogeneous mixture. Step 3, continuous curing: Inject the mixture into the mold cavity and carry out a continuous reaction at 80-100℃ for 10-15 minutes; Step 4, Post-processing: After cooling, cut into a fibrous structure and coat the surface with an oleophobic layer.

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