Nucleating agent, nonwoven fabric and preparation method and application thereof

Abstract

The application discloses a nucleating agent, a non-woven fabric and a preparation method and application thereof. The nucleating agent comprises inorganic nucleating agents and high molecular nucleating agents; the inorganic nucleating agents comprise at least one of carboxyl modified nano-silica, nano-calcium carbonate and sharp titanium type nano-titanium dioxide; the high molecular nucleating agents comprise at least one of a wholly aromatic polyester, ethylene-methacrylic acid copolymer sodium salt and a long chain carboxylic acid salt; and the nucleating agent is in the form of a water dispersion. The nucleating agent comprises inorganic nucleating agents and high molecular nucleating agents, and can quickly induce nucleation at a lower temperature, reduce crystallization enthalpy and significantly improve the crystallization rate, so that the mechanical properties, dimensional stability and thermal stability of the non-woven fabric are enhanced. The use of the nucleating agent makes the fiber structure of the non-woven fabric more uniform and dense, reduces the crystallization temperature, improves the mechanical properties, and reduces shrinkage and deformation during use.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wet non-woven fabric, in particular to a nucleating agent, a non-woven fabric and a preparation method and application thereof. BACKGROUND

[0002] The wet forming process is a method for preparing filter material support materials, the process of which includes dispersing plant or synthetic chemical fibers in water containing special additives to form a uniform suspension slurry. Then, the suspension slurry is transported to a web forming device, and the fibers are formed and dried into a cloth in a wet state. This process has the advantages of fast speed, low processing cost, easy control of pore size and porosity, etc., and one of the main uses is to make support materials for filter membranes.

[0003] The current commonly used filter material support material is polyethylene terephthalate fiber (PET fiber). PET is a semi-crystalline thermoplastic material with high tensile strength, excellent thermal stability, good electrical insulation and low air permeability, etc. Therefore, PET is widely used in the support materials of non-woven fabrics and other filter materials.

[0004] However, the rigid conjugated structure of PET fiber limits the movement of its molecular chain during crystallization, resulting in slow crystallization speed and reduced crystallization ability, thereby affecting the overall mechanical properties of PET. At present, in order to meet the strength requirements of filter material support materials, hot pressing treatment must be carried out at a high temperature of 220-240℃, which has high energy consumption and limits the engineering application of PET-based non-woven fabric support materials.

[0005] To solve this problem, there is prior art that proposes a PET nucleating agent, which uses a complex structure of aromatic polymer lignin as a nucleating agent for PET. Through carboxylation modification, carboxylic acid ion clusters in lignin are introduced to achieve chemical induction nucleation in PET. The mixed PET and nucleating agent are extruded at a temperature range of 240 to 270℃, which effectively improves the crystallization rate and crystallinity of PET.

[0006] On the other hand, there is prior art that introduces another PET nucleating agent, which controls the addition amount of sulfonated dimethyl fumarate and the ionic content of the polymer to prepare a polybutylene succinate ionomer suitable for the PET matrix, thereby optimizing the nucleation effect and crystallization speed of PET.

[0007] However, the prior art has at least four problems, first, the current preparation method mainly adopts melt blending extrusion, resulting in a complex operation process and high operation requirements. Second, in order to reduce the heat treatment temperature during production, different types of low-melting-point bonding fibers or inorganic fibers are usually introduced, and after wet forming, hot pressing is carried out at 180±5℃. This method is prone to sticking to the cylinder during actual operation, which is not conducive to large-scale production. Third, the use of organic small molecule nucleating agents can easily lead to degradation of PET, thereby affecting its mechanical properties. Fourth, the inorganic nucleating agent used has poor dispersibility in the PET matrix, and the nucleation effect is general, which limits the physical and chemical properties of the PET blend, and is not conducive to its industrial application.

[0008] Therefore, it is urgent to develop a new type of wet non-woven fabric and its preparation method to solve the above problems. SUMMARY

[0009] The purpose of the present application is to provide a new type of nucleating agent, so that the non-woven fabric of the present application can achieve extremely high tensile strength at a lower hot pressing temperature.

[0010] The first aspect of the present application is:

[0011] A nucleating agent is provided.

[0012] The second aspect of the present application is:

[0013] A non-woven fabric is provided.

[0014] The third aspect of the present application is:

[0015] A preparation method of a non-woven fabric is provided.

[0016] Specifically, the technical scheme adopted according to the first aspect of the present application is:

[0017] A nucleating agent, comprising an inorganic nucleating agent and a high molecular nucleating agent;

[0018] The inorganic nucleating agent comprises at least one of carboxyl modified nano silicon dioxide, nano calcium carbonate and sharp titanium type nano titanium dioxide;

[0019] The high molecular nucleating agent comprises at least one of a wholly aromatic polyester, an ethylene-methacrylic acid copolymer sodium salt and a long-chain carboxylic acid salt;

[0020] The nucleating agent is in the form of an aqueous dispersion.

[0021] According to the implementation method of the present application, one of the technical schemes has at least one of the following advantages or beneficial effects:

[0022] The nucleating agent of the present application can significantly improve the crystallization behavior and fiber arrangement of PET non-woven fabric during hot pressing by specific inorganic and high molecular components. The carboxyl modified nano-silica and sharp titanium nano-titanium dioxide in the inorganic nucleating agent have high specific surface area and good dispersibility, which makes them uniformly dispersed in the polymer matrix and provides nucleation points for polymer molecular chains, reduces the activation energy required for nucleation, and promotes crystallization. At the same time, these nanoparticles can enhance the mobility of polymer chains through interfacial interaction, reduce the crystallization enthalpy, and thus increase the crystallization rate. The addition of nano-calcium carbonate can also provide additional nucleation points and increase the regular arrangement of fibers through its fine particle structure.

[0023] The high molecular nucleating agent such as fully aromatic polyester, ethylene-methacrylic acid copolymer sodium salt and long-chain carboxylic acid salt has a unique chain segment structure and polar group, which can produce a synergistic effect with PET molecular chains to promote the regular arrangement and crystallization of fibers. The carboxyl sodium ion in the ethylene-methacrylic acid copolymer sodium salt can react with the PET molecular chain to form a product with ionic end groups, and these ionic clusters can act as heterogeneous nucleating agents. The polar group of long-chain carboxylic acid salt can also enhance the nucleation effect.

[0024] The carboxyl group of the carboxyl modified nano-silica can improve the interfacial compatibility and force with PET molecules, promoting the regular arrangement of PET molecular chains; the sharp titanium nano-titanium dioxide, due to its crystal structure and good dispersibility, acts as an effective nucleating agent in the polymer matrix, improving the nucleation efficiency; the carboxyl sodium ion in the ethylene-methacrylic acid copolymer sodium salt reacts with the PET molecular chain to form a product with ionic end groups, which can significantly improve the crystallization rate of PET; the long-chain carboxylic acid salt can form effective nucleation points in the polymer matrix through its long-chain structure and polar group, promote the crystallization process, and enhance the mechanical properties of non-woven fabric through its synergistic effect.

[0025] According to one embodiment of the present application, the particle size of the inorganic nucleating agent is 5-100 nm.

[0026] According to one embodiment of the present application, the particle size of the inorganic nucleating agent is 10-50 nm.

[0027] According to one embodiment of the present application, the nucleating agent is in the form of a water dispersion, which is a water dispersion formed by uniformly dispersing the nucleating agent in water.

[0028] Specifically, the technical scheme adopted according to the second aspect of the present application is:

[0029] A nonwoven fabric comprising polyethylene terephthalate fibers and a nucleating agent coated on the polyethylene terephthalate fibers using a curtain coating, slot coating, or flow coating method.

[0030] According to the implementation method of the present application, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0031] The coating method of the nucleating agent ensures its uniform distribution on the surface of the fibers, providing a large number of uniform nucleation sites and significantly improving the crystallization rate and crystallinity of PET fibers. The improved crystallinity can enhance the mechanical properties of the nonwoven fabric, such as tensile strength, tear strength, and impact resistance, making it more durable and robust.

[0032] In addition, the uniform distribution of the nucleating agent reduces the internal stress and shrinkage deformation of the fibers during cooling and solidification, improving the dimensional stability of the nonwoven fabric. Since the nucleating agent has good thermal stability at high temperatures, the coated nonwoven fabric can still maintain physical and chemical stability in high-temperature environments, significantly improving the heat resistance.

[0033] The nanoscale particle size and uniform dispersion characteristics of the nucleating agent reduce light scattering, thereby improving the transparency and optical performance of the nonwoven fabric, making it more aesthetically pleasing and functional in certain applications. Finally, the process of coating the nucleating agent not only shortens the production cycle of the nonwoven fabric and improves production efficiency, but also ensures the stable distribution of the nucleating agent during the coating process, avoiding agglomeration problems and further optimizing the processing performance.

[0034] Specifically, the technical solution adopted according to the third aspect of the present application is:

[0035] A method for preparing the nonwoven fabric, comprising the following steps:

[0036] S1 mixing polyethylene terephthalate fibers in water to obtain a slurry;

[0037] S2 forming the slurry into a sheet to obtain a PET nonwoven fabric, and coating the nucleating agent on the PET nonwoven fabric using a curtain coating or flow coating method to obtain a paper sheet;

[0038] S3 drying, winding, and rolling the paper sheet to obtain the nonwoven fabric.

[0039] According to the implementation method of the present application, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0040] Firstly, the method of the present application is simple and easy to operate. The nucleating agent is added once during the wet forming of PET fibers to form a controllable non-woven fabric material. The method does not require complex equipment and process, is suitable for large-scale production, and can significantly improve production efficiency. In addition, due to the simple process, the cost of equipment and materials required is low, thereby reducing the overall production cost.

[0041] The coating method of the nucleating agent ensures its uniform distribution on the PET non-woven fabric, and after cooling and solidification, it is like a mortise and tenon structure, which can quickly induce nucleation during hot pressing at a lower temperature, thereby enhancing the strength of the non-woven fabric. This coating method enables the nucleating agent to effectively function above the crystallization temperature of PET fibers, promoting the fibers to arrange more regularly for crystallization. The nucleating agent can reduce the crystallization enthalpy, thereby significantly improving the crystallization speed of PET fibers. This not only improves the crystallinity and crystallization rate of the fibers and improves the mechanical properties of the non-woven fabric, but also enables the non-woven fabric to achieve ideal tensile strength at a lower hot pressing temperature, thereby improving the performance and quality of the product.

[0042] Through uniform coating of the nucleating agent and appropriate heat treatment, the final non-woven fabric has excellent mechanical properties, including higher tensile strength and tear strength. At the same time, the addition of the nucleating agent enables the non-woven fabric to maintain physical and chemical stability in a high-temperature environment, thereby significantly improving its thermal stability and dimensional stability.

[0043] This method not only optimizes the crystallization process of PET fibers and improves the overall performance of the non-woven fabric, but also simplifies the production process and reduces costs, thereby achieving an efficient and economical production mode. In summary, the method for preparing a non-woven fabric promotes rapid crystallization of the fibers and uniform coating of the nucleating agent, thereby improving the quality and performance of the product, and has the advantages of simple operation, high production efficiency, and low cost.

[0044] According to one embodiment of the present application, the mass percentage of polyethylene terephthalate fibers in the slurry is 1-5%.

[0045] According to one embodiment of the present application, the mass percentage of polyethylene terephthalate fibers in the slurry is 2-4%.

[0046] According to one embodiment of the present application, in step S2, the basis weight of the PET non-woven fabric is 15-100 / m 2 .

[0047] According to one embodiment of the present application, in step S2, the basis weight of the PET non-woven fabric is 65-73 / m 2 .

[0048] According to an implementation method of the present application, in step S2, the nucleating agent is coated on the PET non-woven fabric by using a curtain coating, slot coating or flow coating method to obtain a wet paper sheet, and the wet paper sheet is dried to obtain a paper sheet.

[0049] According to an implementation method of the present application, in step S2, the nucleating agent is in the form of a water dispersion, and the mass percentage concentration of the nucleating agent is 2-15%.

[0050] According to an implementation method of the present application, in step S3, the temperature of the metal roller during the heat pressing treatment is 190-210°C.

[0051] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the following description, or can be learned by practice of the present application. DETAILED DESCRIPTION

[0052] The words "preferably", "more preferably", and the like, used herein mean certain embodiments of the application which can provide certain benefits under certain circumstances. However, other embodiments can also be preferred or more preferred under the same or other circumstances. Additionally, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude those other embodiments from the scope of the application.

[0053] When a numerical range is disclosed herein, the range is to be construed as continuous, and to include each and every value and sub-range within the range. Further, when a range is disclosed, the range is inclusive of the minimum and maximum values, and of each integer within the range. Further, when a plurality of ranges is provided, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood as encompassing both the smallest and largest values, and also each and every intervening value between the smallest and largest values. Further, unless otherwise indicated, all limits in a range are inclusive. The use of "about" or "approximately" in connection with a range applies to both ends of the range. It will be further noted that the limits of both the lower and upper range are included in the range, i.e. the range is closed. Also, a range includes the singular unless otherwise indicated. The use of "or" in the

[0054] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0055] The reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the technical field unless otherwise specified.

[0056] In the examples and comparative examples, the carboxyl-modified nano-silica water dispersion was purchased from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd., model: XEF31-2.

[0057] In the examples and comparative examples, the ethylene-methacrylic acid copolymer sodium salt was purchased from Shanghai Zhenjun Biological Technology Co., Ltd., item number: 55207314.

[0058] In the examples and comparative examples, the anatase type nano titanium dioxide was purchased from Beijing Dekedaojin Technology Co., Ltd., batch number: 20240506.

[0059] In the examples and comparative examples, the rutile type nano titanium dioxide was purchased from Jiangsu Tianxing New Material Co., Ltd., model TTP-R20.

[0060] Example 1

[0061] A nucleating agent, comprising the following components: a carboxyl-modified nano-silica aqueous dispersion and an ethylene-methacrylic acid copolymer sodium salt dispersion, wherein the particle size of the carboxyl-modified nano-silica is 10 nm.

[0062] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0063] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0064] S1 mixing polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration being 2%, after sufficient dispersion and mixing, a slurry is obtained, and a water dilution pump is used to dilute the slurry to a web concentration of about 0.03%;

[0065] S2 feeding the slurry through the corresponding flow channel into an inclined net former to form a PET non-woven fabric, the basis weight of the PET non-woven fabric being 70 g / m 2 Before entering the drying section, a carboxyl-modified nano-silica aqueous dispersion with a mass percentage concentration of 5% and a 5% ethylene-methacrylic acid copolymer sodium salt dispersion are coated on the PET non-woven fabric by using the method of slope flow, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0066] S3 drying the wet paper sheet through multiple cylinders to obtain a dry paper sheet, the temperature of the multiple cylinder drying being set from the front cylinder to the rear cylinder as 125°C, and the dry paper sheet is obtained; the dry paper sheet is treated by a metal roller with a temperature of 190°C to obtain a non-woven fabric, and the basis weight of the non-woven fabric is controlled at 75 g / m 2 .

[0067] Example 2

[0068] The difference between Example 2 and Example 1 is that the nucleating agents are different. In Example 2, the nucleating agent is an ethylene-methacrylic acid copolymer sodium salt dispersion and an anatase type nano titanium dioxide dispersion.

[0069] A nucleating agent comprising the following components: an ethylene-methacrylic acid copolymer sodium salt dispersion liquid and a sharp titanium type nano titanium dioxide dispersion liquid.

[0070] A nonwoven fabric comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0071] A method for manufacturing the above-mentioned nonwoven fabric, comprising the following steps:

[0072] S1 mixing polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration being 2%, after sufficient dispersion and mixing, a slurry is obtained, and a slurry pump is used to dilute the water to an on- wire concentration of about 0.03%;

[0073] S2 feeding the slurry through the corresponding flow channel into an inclined net former to be formed by papermaking, to obtain a PET nonwoven fabric, the basis weight of the PET nonwoven fabric being 70g / m 2 Before entering the drying section, 5% of the ethylene-methacrylic acid copolymer sodium salt dispersion liquid and 5% of the sharp titanium type nano titanium dioxide dispersion liquid are coated on the PET nonwoven fabric by the method of slope flow, and the nucleating agent penetrates into the PET nonwoven fabric to form a wet paper sheet together;

[0074] S3 drying the wet paper sheet through multiple cylinders to obtain a dry paper sheet, the temperature of the multiple cylinder drying being set from the front cylinder to the rear cylinder as 125℃, to obtain a dry paper sheet; the dry paper sheet is treated by a metal roller with a temperature of 190℃, to obtain a nonwoven fabric, the basis weight of the nonwoven fabric being controlled at 75g / m 2 .

[0075] Example 3

[0076] Example 3 is different from Example 1 in that the rolling temperature is different. In Example 3, the rolling temperature is 210℃.

[0077] A nucleating agent comprising the following components: a carboxyl-modified nano-silica water dispersion liquid and an ethylene-methacrylic acid copolymer sodium salt dispersion liquid, wherein the particle size of the carboxyl-modified nano-silica is 10nm.

[0078] A nonwoven fabric comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0079] A method for manufacturing the above-mentioned nonwoven fabric, comprising the following steps:

[0080] S1 mixing polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration being 2%, after sufficient dispersion and mixing, a slurry is obtained, and a slurry pump is used to dilute the water to an on- wire concentration of about 0.03%;

[0081] S2 passes the slurry through the corresponding flow channel into the inclined wire former to be formed by the wet laying to obtain the PET non-woven fabric, and the basis weight of the PET non-woven fabric is 70 g / m 2 Before entering the drying section, the carboxyl modified nano-silica water dispersion liquid with a mass percentage concentration of 5% and the 5% ethylene-methacrylic acid copolymer sodium salt dispersion liquid are coated on the PET non-woven fabric by using the slope flow method, and the nucleating agent penetrates into the PET non-woven fabric to form the wet paper sheet together;

[0082] S3 passes the wet paper sheet through the multi-cylinder drying treatment to obtain the dry paper sheet, the temperature of the multi-cylinder drying is set to be 125℃ from the front cylinder to the rear cylinder, and the dry paper sheet is obtained; the dry paper sheet is treated by the metal roller with a temperature of 210℃ to obtain the non-woven fabric, and the basis weight of the non-woven fabric is controlled to be 75 g / m 2 .

[0083] Example 4

[0084] The difference between Example 4 and Example 1 is that the concentration of the nucleating agent is different, and the basis weight of the PET non-woven fabric is different. In Example 4, the mass percentage of the nucleating agent is 2%, and the basis weight of the PET non-woven fabric is 73 g / m 2 .

[0085] A nucleating agent, comprising the following components: a carboxyl modified nano-silica water dispersion liquid and an ethylene-methacrylic acid copolymer sodium salt dispersion liquid, wherein the particle size of the carboxyl modified nano-silica is 10 nm.

[0086] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0087] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0088] S1 mixes polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration is 2%, and after being fully dispersed and mixed, a slurry is obtained, and the slurry is diluted to a headbox concentration of about 0.03% by using a slurry pump to add water;

[0089] S2 passes the slurry through the corresponding flow channel into the inclined wire former to be formed by the wet laying to obtain the PET non-woven fabric, and the basis weight of the PET non-woven fabric is 73 g / m 2 Before entering the drying section, the carboxyl modified nano-silica water dispersion liquid with a mass percentage concentration of 2% and the 2% ethylene-methacrylic acid copolymer sodium salt dispersion liquid are coated on the PET non-woven fabric by using the slope flow method, and the nucleating agent penetrates into the PET non-woven fabric to form the wet paper sheet together;

[0090] S3 passes the wet paper sheet through multi-cylinder drying treatment to obtain dry paper sheet, the temperature from the front cylinder to the rear cylinder is set to 125℃ during the multi-cylinder drying, and the dry paper sheet is obtained; the dry paper sheet is treated through a metal roller with a temperature of 190℃ to obtain the non-woven fabric, and the non-woven fabric is quantitatively controlled at 75g / m 2 .

[0091] Example 5

[0092] The difference between Example 5 and Example 1 is that the concentration of the nucleating agent is different, and the basis weight of the PET non-woven fabric is different. In Example 5, the mass percentage of the nucleating agent is 8%, and the basis weight of the PET non-woven fabric is 68g / m 2 .

[0093] A nucleating agent, comprising the following components: a carboxyl-modified nano-silica aqueous dispersion and an ethylene-methacrylic acid copolymer sodium salt dispersion, wherein the particle size of the carboxyl-modified nano-silica is 10nm.

[0094] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0095] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0096] S1 mixes polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration is 2%, after sufficient dispersion and mixing, a slurry is obtained, and a water dilution pump is used to dilute the slurry to a web concentration of about 0.03%;

[0097] S2 passes the slurry through a corresponding flow channel into an inclined net former to be formed into a PET non-woven fabric, and the basis weight of the PET non-woven fabric is 68g / m 2 Before entering the drying part, a carboxyl-modified nano-silica aqueous dispersion with a mass percentage of 8% and an ethylene-methacrylic acid copolymer sodium salt dispersion with a mass percentage of 8% are coated on the PET non-woven fabric by using the method of slope flow, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0098] S3 passes the wet paper sheet through multi-cylinder drying treatment to obtain dry paper sheet, the temperature from the front cylinder to the rear cylinder is set to 125℃ during the multi-cylinder drying, and the dry paper sheet is obtained; the dry paper sheet is treated through a metal roller with a temperature of 190℃ to obtain the non-woven fabric, and the non-woven fabric is quantitatively controlled at 75g / m 2 .

[0099] Example 6

[0100] The difference between Example 6 and Example 1 is that the particle size of the nucleating agent is different. In Example 6, the particle size of the nucleating agent is 50nm.

[0101] A nucleating agent comprising the following components: a carboxyl-modified nano-silica aqueous dispersion and an ethylene-methacrylic acid copolymer sodium salt dispersion, wherein the carboxyl-modified nano-silica has a particle size of 50 nm.

[0102] A nonwoven fabric comprising polyethylene terephthalate fibers and the above nucleating agent.

[0103] A method for manufacturing the above nonwoven fabric, comprising the following steps:

[0104] S1 mixing polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration being 2%, after sufficient dispersion and mixing, a slurry is obtained, and a slurry pump is used to dilute the slurry with water to an on- wire concentration of about 0.03%;

[0105] S2 feeding the slurry through a corresponding flow channel into an inclined net former to be formed by papermaking, to obtain a PET nonwoven fabric, the basis weight of the PET nonwoven fabric being 70 g / m 2 Before entering the drying section, a carboxyl-modified nano-silica aqueous dispersion with a mass percentage concentration of 5% and a 5% ethylene-methacrylic acid copolymer sodium salt dispersion are coated on the PET nonwoven fabric by using the method of slope flow, and the nucleating agent penetrates into the PET nonwoven fabric to form a wet paper sheet together;

[0106] S3 drying the wet paper sheet through multiple cylinders to obtain a dry paper sheet, the temperature of the multiple cylinders is set from the front cylinder to the rear cylinder to be 125°C, to obtain a dry paper sheet; the dry paper sheet is treated by a metal roller with a temperature of 190°C to obtain a nonwoven fabric, and the basis weight of the nonwoven fabric is controlled to be 75 g / m 2 .

[0107] Example 7

[0108] Example 7 differs from Example 1 in that the coating method is different.

[0109] A nucleating agent comprising the following components: a carboxyl-modified nano-silica aqueous dispersion and an ethylene-methacrylic acid copolymer sodium salt dispersion, wherein the carboxyl-modified nano-silica has a particle size of 10 nm.

[0110] A nonwoven fabric comprising polyethylene terephthalate fibers and the above nucleating agent.

[0111] A method for manufacturing the above nonwoven fabric, comprising the following steps:

[0112] S1 mixing polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration being 2%, after sufficient dispersion and mixing, a slurry is obtained, and a slurry pump is used to dilute the slurry with water to an on- wire concentration of about 0.03%;

[0113] S2 sends the slurry into the inclined wire former through the corresponding flow channel to be formed by papermaking, to obtain PET non-woven fabric, and the basis weight of the PET non-woven fabric is 70 g / m 2 Before entering the drying section, a carboxyl modified nano-silica water dispersion liquid with a mass percentage concentration of 5% and a 5% ethylene-methacrylic acid copolymer sodium salt dispersion liquid are coated on the PET non-woven fabric by using a curtain coating method, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0114] S3 obtains a dry paper sheet by subjecting the wet paper sheet to multi-cylinder drying treatment, and the temperature from the front cylinder to the rear cylinder is set to 125°C during the multi-cylinder drying, to obtain a dry paper sheet; and the dry paper sheet is subjected to treatment by a metal roller with a temperature of 190°C, to obtain non-woven fabric, and the basis weight of the non-woven fabric is controlled to be 75 g / m 2 .

[0115] Example 8

[0116] Example 8 is different from example 1 in that the coating method is different.

[0117] A nucleating agent, comprising the following components: a carboxyl modified nano-silica water dispersion liquid and an ethylene-methacrylic acid copolymer sodium salt dispersion liquid, wherein the particle size of the carboxyl modified nano-silica is 10 nm.

[0118] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0119] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0120] S1 mixes polyethylene terephthalate fibers (PET fibers) with water, and the fiber concentration is 2%, and after being fully dispersed and mixed, a slurry is obtained, and a water dilution pump is used to dilute the slurry to an on-line concentration of about 0.03%;

[0121] S2 sends the slurry into the inclined wire former through the corresponding flow channel to be formed by papermaking, to obtain PET non-woven fabric, and the basis weight of the PET non-woven fabric is 70 g / m 2 Before entering the drying section, a carboxyl modified nano-silica water dispersion liquid with a mass percentage concentration of 5% and a 5% ethylene-methacrylic acid copolymer sodium salt dispersion liquid are coated on the PET non-woven fabric by using a curtain coating method, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0122] S3 obtains a dry paper sheet by subjecting the wet paper sheet to multi-cylinder drying treatment, and the temperature from the front cylinder to the rear cylinder is set to 125°C during the multi-cylinder drying, to obtain a dry paper sheet; and the dry paper sheet is subjected to treatment by a metal roller with a temperature of 190°C, to obtain non-woven fabric, and the basis weight of the non-woven fabric is controlled to be 75 g / m 2 .

[0123] Comparative Example 1

[0124] The difference between Comparative Example 1 and Example 1 is that the nucleating agent is different. In Comparative Example 1, the nucleating agent is only 5% carboxyl-modified nano-silica water dispersion.

[0125] A nucleating agent, comprising the following components: 5% carboxyl-modified nano-silica water dispersion, wherein the particle size of the carboxyl-modified nano-silica in the carboxyl-modified nano-silica water dispersion is 10 nm.

[0126] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0127] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0128] S1 mixing polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration being 2%, after sufficient dispersion and mixing, obtaining a slurry, and diluting with a slurry pump to about 0.03% of the on- wire concentration;

[0129] S2 feeding the slurry through the corresponding flow channel into an inclined net former to be formed by papermaking, obtaining a PET non-woven fabric, the basis weight of the PET non-woven fabric being 70 g / m 2 Before entering the drying section, using the method of slope flow to coat 5% carboxyl-modified nano-silica water dispersion on the PET non-woven fabric, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0130] S3 drying the wet paper sheet through multiple cylinders to obtain a dry paper sheet, the temperature of the multiple cylinder drying being set from the front cylinder to the rear cylinder to be 125°C, obtaining a dry paper sheet; treating the dry paper sheet through a metal roller with a temperature of 190°C to obtain a non-woven fabric, the basis weight of the non-woven fabric being controlled to be 75 g / m 2 .

[0131] Comparative Example 2

[0132] The difference between Comparative Example 2 and Example 1 is that the nucleating agent is different. In Comparative Example 2, the nucleating agent is only an ethylene-methacrylic acid copolymer sodium salt dispersion.

[0133] A nucleating agent, comprising the following components: an ethylene-methacrylic acid copolymer sodium salt dispersion.

[0134] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0135] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0136] S1 mixes polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration is 2%, after sufficient dispersion and mixing, a slurry is obtained, and water is added by a slurry pump to dilute to an approach net concentration of about 0.03%;

[0137] S2 sends the slurry into an inclined net former through a corresponding flow channel to be formed by papermaking, to obtain a PET non-woven fabric, and the basis weight of the PET non-woven fabric is 70 g / m 2 Before entering the drying part, a 5% ethylene-methacrylic acid copolymer sodium salt dispersion liquid is coated on the PET non-woven fabric by using a slope flow method, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0138] S3 processes the wet paper sheet through multi-cylinder drying to obtain a dry paper sheet, and the temperature of the multi-cylinder drying is set to 125°C from the front cylinder to the rear cylinder to obtain the dry paper sheet; the dry paper sheet is processed through a metal roller with a temperature of 190°C to obtain a non-woven fabric, and the basis weight of the non-woven fabric is controlled to be 75 g / m 2 .

[0139] Comparative Example 3

[0140] Comparative Example 3 and Example 1 differ in that the nucleating agent is different. In Comparative Example 3, the nucleating agent is montmorillonite.

[0141] A nucleating agent, comprising the following components: a montmorillonite water dispersion liquid, wherein the particle size of the montmorillonite is 10 nm.

[0142] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0143] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0144] S1 mixes polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration is 2%, after sufficient dispersion and mixing, a slurry is obtained, and water is added by a slurry pump to dilute to an approach net concentration of about 0.03%;

[0145] S2 sends the slurry into an inclined net former through a corresponding flow channel to be formed by papermaking, to obtain a PET non-woven fabric, and the basis weight of the PET non-woven fabric is 70 g / m 2 Before entering the drying part, a 5% ethylene-methacrylic acid copolymer sodium salt dispersion liquid is coated on the PET non-woven fabric by using a slope flow method, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0146] S3 processes the wet paper sheet through multi-cylinder drying to obtain a dry paper sheet, and the temperature of the multi-cylinder drying is set to 125°C from the front cylinder to the rear cylinder to obtain the dry paper sheet; the dry paper sheet is processed through a metal roller with a temperature of 190°C to obtain a non-woven fabric, and the basis weight of the non-woven fabric is controlled to be 75 g / m2 .

[0147] Comparative Example 4

[0148] The difference between Comparative Example 4 and Example 1 is that the nucleating agent is different. In Comparative Example 4, the nucleating agent is only a dispersion liquid of nanometer titanium dioxide in rutile form.

[0149] A nucleating agent, comprising the following components: a dispersion liquid of nanometer titanium dioxide in rutile form.

[0150] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0151] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0152] S1 mixing polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration being 2%, after sufficient dispersion and mixing, a slurry is obtained, and a water dilution pump is used to dilute the slurry to a web concentration of about 0.03%;

[0153] S2 feeding the slurry through a corresponding flow channel into an inclined net former to be formed by papermaking, to obtain a PET non-woven fabric, the basis weight of the PET non-woven fabric being 70g / m 2 Before entering the drying section, a dispersion liquid of nanometer titanium dioxide in rutile form with a mass percentage concentration of 5% is coated on the PET non-woven fabric by using the method of slope flow, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0154] S3 drying the wet paper sheet through multiple cylinders to obtain a dry paper sheet, the temperature of the multiple cylinder drying being set from the front cylinder to the rear cylinder as 125℃, to obtain a dry paper sheet; the dry paper sheet is treated through a metal roller with a temperature of 190℃, to obtain a non-woven fabric, the basis weight of the non-woven fabric being controlled at 75g / m 2 .

[0155] Comparative Example 5

[0156] The difference between Comparative Example 5 and Example 1 is that the nucleating agent is different. In Comparative Example 5, the nucleating agent is sodium 2-chloro-4-nitrobenzoate.

[0157] A nucleating agent, comprising the following components: a water dispersion liquid of sodium 2-chloro-4-nitrobenzoate.

[0158] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0159] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0160] S1 mixes polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration is 2%, after sufficient dispersion and mixing, a slurry is obtained, and a water dilution pump is used to dilute to a wire concentration of about 0.03%;

[0161] S2 sends the slurry into the inclined wire former through the corresponding flow channel to form a PET non-woven fabric, and the basis weight of the PET non-woven fabric is 70g / m 2 Before entering the drying section, a 5% mass percentage concentration of 2-chloro-4-nitrobenzoic acid sodium water dispersion is coated on the PET non-woven fabric by using the method of slope flow, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0162] S3 processes the wet paper sheet through a multi-cylinder drying process to obtain a dry paper sheet, and the temperature of the multi-cylinder drying process is set from the front cylinder to the rear cylinder to be 125°C, and the dry paper sheet is obtained; the dry paper sheet is processed through a metal roller with a temperature of 190°C to obtain a non-woven fabric, and the basis weight of the non-woven fabric is controlled to be 75g / m 2 .

[0163] Comparative Example 6

[0164] The difference between Comparative Example 6 and Example 1 is that the particle size of the nucleating agent is different. In Comparative Example 6, the particle size of the nucleating agent is 300nm.

[0165] A nucleating agent, comprising the following components: a carboxyl-modified nano-silica water dispersion, wherein the particle size of the carboxyl-modified nano-silica is 300nm.

[0166] A non-woven fabric, comprising polyethylene terephthalate fibers and the above-mentioned nucleating agent.

[0167] A method for preparing the above-mentioned non-woven fabric, comprising the following steps:

[0168] S1 mixes polyethylene terephthalate fibers (PET fibers) with water, the fiber concentration is 2%, after sufficient dispersion and mixing, a slurry is obtained, and a water dilution pump is used to dilute to a wire concentration of about 0.03%;

[0169] S2 sends the slurry into the inclined wire former through the corresponding flow channel to form a PET non-woven fabric, and the basis weight of the PET non-woven fabric is 70g / m 2 Before entering the drying section, a 5% mass percentage concentration of 2-chloro-4-nitrobenzoic acid sodium water dispersion is coated on the PET non-woven fabric by using the method of slope flow, and the nucleating agent penetrates into the PET non-woven fabric to form a wet paper sheet together;

[0170] S3 passes the wet paper sheet through a multi-cylinder drying process to obtain a dry paper sheet, and the temperature of the multi-cylinder drying process is set to 125°C from the front cylinder to the rear cylinder to obtain the dry paper sheet; and the dry paper sheet is treated by a metal roller at a temperature of 190°C to obtain a non-woven fabric, and the non-woven fabric is controlled at a basis weight of 75g / m2. 2 .

[0171] Comparative Example 7

[0172] The difference between Comparative Example 7 and Comparative Example 1 is that no nucleating agent is used in the process of preparing the non-woven fabric in Comparative Example 7.

[0173] The non-woven fabrics prepared in Examples 1-8 and Comparative Examples 1-7 can be further obtained as wet non-woven fabrics for filter membranes after trimming and winding.

[0174] Performance test:

[0175] The tensile strength of the non-woven fabrics of Examples 1-8 and Comparative Examples 1-7 is tested by the following method: each non-woven fabric is cut into a long strip with a width of 15mm and a length of about 150mm, and a tensile strength tester is used to test the tensile strength of the non-woven fabric, and the test results are shown in Table 1.

[0176] Table 1

[0177]

[0178] Compared with Comparative Example 7 (blank sample without nucleating agent), the strength of the PET non-woven fabric using the nucleating agent in Examples 1-8 is significantly improved; and it can be found from Example 3 that the strength of the PET non-woven fabric support material using the nucleating agent is also significantly improved as the hot-pressing temperature increases.

[0179] As can be seen from the comparison between Examples 1-2 and Comparative Examples 1-2, the tensile strength of the non-woven fabric using the composite nucleating agent is higher than that of the non-woven fabric using a single nucleating agent. The main reasons are as follows: on the one hand, the PET molecular chain will be adsorbed onto the inorganic nucleating agent particles and arranged in order to form a crystal nucleus, and these inorganic nucleating agents as heterogeneous nucleating agents reduce the activation energy required for the PET to form a crystal nucleus; on the other hand, the high molecular nucleating agent has a flexible group on the macromolecule with an ionic end group, and the flexible group chain is more flexible than the PET molecular chain, which plays a role of a promoter in the system, promotes the molecular movement of the PET, and reduces the free energy of the molecular chain diffusing into the crystal lattice, thereby improving the crystallization rate and surface compatibility of the PET.

[0180] Meanwhile, from Example 1-2 and Example 7-8, it can be seen that the effect of coating by adopting the slope flow mode is better than that of curtain coating and slit coating, and the main reason is that by adopting the slope flow mode, the inorganic and high molecular composite nucleating agent is more likely to form a uniform and stable slope coating into the PET non-woven fabric; while using curtain coating, the effect of the curtain of the composite nucleating agent dispersion liquid is poor, which leads to uneven coating or penetration into the PET non-woven fabric, affecting its use effect. When using slit coating, the coating head and the backing roller have a certain angle, which affects the penetration of the nucleating agent, thereby limiting the effect of the nucleating agent penetrating into the PET non-woven fabric, which will also affect the final use effect of the nucleating agent.

[0181] In addition, through a large number of experiments, it is found that if an inappropriate nucleating agent is selected, the strength of the PET non-woven fabric is limited to improve, and even has a negative effect. For example, in Comparative Example 4, rutile titanium dioxide is used, and because its crystal lattice is more dense, it has higher hardness and poor dispersibility in water, which affects the nucleation effect.

[0182] The effects of montmorillonite in Comparative Example 3, 2-chloro-4-nitrobenzoic acid sodium in Comparative Example 5 and large particle size carboxyl modified nano silicon dioxide in Comparative Example 6 are poor. The main reasons are analyzed as follows: the lamellar structure of montmorillonite will increase the "physical crosslinking point" between the crystal nuclei after the addition amount is increased, which has a negative effect on the crystallization of PET; 2-chloro-4-nitrobenzoic acid sodium is easy to react with PET during heat treatment, which reduces the mechanical properties of PET; large particle size carboxyl modified nano silicon dioxide is not conducive to inducing crystallization due to its large particle size, and has no promoting effect on the tensile strength.

[0183] The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent transformation or direct or indirect application in related technical fields using the content of the present application specification is also included in the patent protection scope of the present application.

Claims

1. A method of making a nonwoven fabric, characterized by: The method comprises the following steps: S1 mixing polyethylene terephthalate fibers in water to obtain a slurry; S2 forming the slurry into a sheet to obtain a PET non-woven fabric, and coating a nucleating agent on the PET non-woven fabric by using a curtain coating method to obtain a paper sheet; S3 drying, winding and hot pressing the paper sheet to obtain a non-woven fabric; The nucleating agent comprises an inorganic nucleating agent and a high molecular nucleating agent; The inorganic nucleating agent is at least one of carboxyl-modified nano-silica, nano-calcium carbonate and anatase nano-titanium dioxide; The high molecular nucleating agent is at least one of a wholly aromatic polyester, an ethylene-methacrylic acid copolymer sodium salt and a long-chain carboxylic acid salt; The nucleating agent is in the form of an aqueous dispersion; The particle size of the inorganic nucleating agent is 5-100 nm.

2. The method of claim 1, wherein: The mass percentage of the polyethylene terephthalate fibers in the slurry is 1-5%.

3. The method of claim 1, wherein: In step S2, the basis weight of the PET nonwoven fabric is 15 to 100 g / m 2 .

4. The method of claim 1, wherein: In step S2, the nucleating agent is coated on the PET non-woven fabric by using a curtain coating, curtain coating, slot coating or curtain coating method to obtain a wet paper sheet, and the wet paper sheet is dried to obtain a paper sheet.

5. The method of claim 1, wherein: In step S2, the nucleating agent is in the form of an aqueous dispersion, and the mass percentage concentration of the nucleating agent is 2-15%.

6. The method of claim 1, wherein: In step S3, the temperature of the metal roller during the hot pressing treatment is 190-210℃.

7. A nonwoven fabric, characterized by: The non-woven fabric is prepared by the method of any one of claims 1-6, and comprises polyethylene terephthalate fibers and a nucleating agent coated on the polyethylene terephthalate fibers by using a curtain coating, curtain coating, slot coating or curtain coating method; The nucleating agent comprises an inorganic nucleating agent and a high molecular nucleating agent; The inorganic nucleating agent is at least one of carboxyl-modified nano-silica, nano-calcium carbonate and anatase nano-titanium dioxide; The high molecular nucleating agent is at least one of a wholly aromatic polyester, an ethylene-methacrylic acid copolymer sodium salt and a long-chain carboxylic acid salt; The nucleating agent is in the form of an aqueous dispersion; The particle size of the inorganic nucleating agent is 5-100 nm.

8. A nonwoven fabric according to claim 7, characterized in that: The particle size of the inorganic nucleating agent is 10-50 nm.

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