WO2023219590A1

WO2023219590A1 - Fire proof and flame retardant polyacrylate fiber and production method thereof

Info

Publication number: WO2023219590A1
Application number: PCT/TR2023/050421
Authority: WO
Inventors: Ali Demirci
Original assignee: Aksa Akrilik Kimya Sanayii Anonim Sirketi
Priority date: 2022-05-11
Filing date: 2023-05-08
Publication date: 2023-11-16

Abstract

The invention belongs to the textile field and relates to a production method with an efficient, continuous, and sustainable approach with the application of optimized process environment conditions and parameters by selecting crosslinker and metal salt suitable for the production of polyacrylate fibers with high potential as raw material in the production of textile products with many different functions. In this way, a more environmentally friendly and sustainable product is presented as it has a lower cycle cost-energy consumption with high LOI values for the related technical field, shows an increase in efficiency, reduces water consumption, reduces carbon footprint, and minimizes waste-by-product disposal.

Description

FIRE PROOF AND FLAME RETARDANT POLYACRYLATE FIBER AND PRODUCTION METHOD THEREOF

TECHNICAL FIELD

The invention provides a production method for polyacrylate fibers with non-flammable and fire-resistant properties. In the invention, with the selection of a suitable multi-amine functional crosslinker that increases non-flammable and fire resistance performance in the polyacrylate fiber production process steps, it is possible to obtain non-flammable and heat resistant polyacrylate fibers by ensuring the application of metal ions-fiber bonding under optimized conditions with appropriate metal salt selection.

BACKGROUND

Acrylic fiber is obtained in various thicknesses and intersecting morphologies as a result of converting the homopolymer or copolymer containing 85% or more by weight of acrylonitrile monomer into solution form with the help of at least one solvent and then applying the wet/dry methods known in the art from these solutions. Additional methods may be developed, or chemicals may be added in order to improve their chemical-physical properties and performances in order to obtain an acrylic fiber product suitable for the needs and sector of the consumer during the process steps. Acrylic fiber is a type of fiber frequently used in the technical field related to its ability to be washed as a synthetic fiber and not to maintain its shape, to provide resistance to moth, oil, and chemicals, to be painted in colors, to have high fastness properties to sunlight and heat as a synthetic fiber. These properties of the acrylic fiber are easily flammable and combustible depending on the ambient oxygen level in the presence of flame. The limit amount of oxygen (hereafter abbreviated as LOI) needed for combustion is around 18-19% LOL The production of flame and heat resistant acrylic fibers by chemical technologies and methods can be done by creating a coating on the surface of the halogen-containing acrylonitrile copolymer as obtained by using inorganic synergistic components or by chemical modifications of acrylonitrile-containing polymers.

The modification of the polyacrylate fiber, acrylonitrile-containing polymer is prepared by undergoing a series of chemical reaction processes, demonstrating high thermal and flameresistant performance, and has high thermal insulation, hygroscopic, acid-base buffer, and easy dyeing properties with low heat transfer coefficient. Thanks to the mentioned features, polyacrylate fibers are a type of fiber that is frequently used in the related technical field. Polyacrylate fibers are obtained from acrylic fibers by methods known in the art. Said production method comprises the following process steps: i. crosslinking at least part of the nitrile (abbreviated as -CN) chemical groups within the acrylic fiber with at least one crosslinker(s);

- carrying out said process step at high performance and identifying suitable crosslinkers in order to provide high LOI values to the final product, ii. adding the reactive nitrile groups contained in the acrylic fiber that has not reacted with the crosslinkers to the alkaline medium to form the acrylate salt by hydrolysis;

- efficient and complete conversion of the fiber-forming polymer to its acrylates (- COO-M +) by the reaction of metal alkali salt hydrolysis of non-crosslinked nitrile groups is required in order to perform said process step at high performances, iii. performing neutralization processes with at least one acid to ensure the neutralization of pH values;

- Neutralization of the acrylate chemical group on the polymer forming the fiber after alkaline hydrolysis with acid, carboxylic acid conversion rate, and determination of chemical condition parameters, iv. ionizing metal organic-inorganic ionic salts in the presence of a solvent to form a di- and tri-valent metal-chelate ionic complex with metal ions and carboxylic acid groups,

- The selection of metal salt suitable for the polyvalent metal complex formation of the carboxylic acid chemical groups of the polymer forming the fiber, as well as the conditions that form the metal ions and the determination of the necessary parameters to bind to the fiber directly affect the non-flammability properties and performances. The polyacrylate fiber can be produced by a four-stage industrial batch process production method, the non-flammability feature and performance of which each stage includes the process environment and conditions in itself;

- The selection of the appropriate multi-amine functional chemical for chemical crosslinking of the polymer chains forming the fiber and determining the environmental conditions,

Functional efficient and complete conversion of acrylate (-COO-M +) by the reaction of metal alkali salt hydrolysis of Nitrile groups not subjected to crosslinking of the polymer forming the fiber,

- Neutralization of acrylate chemical group on the fiber-forming polymer with acid after alkali hydrolysis, carboxylic acid conversion rate, and chemical condition parameters,

- The selection of metal salt suitable for the polyvalent metal complex formation of the carboxylic acid chemical groups of the polymer forming the fiber, as well as the conditions that form the metal ions and the determination of the necessary parameters to bind to the fiber directly affect the flammability properties and performances.

The LOI value of the polyacrylate fibers obtained by applying the process steps of crosslinking-acrylate salt formation-neutralization-complex formation in the state of the art from acrylic fibers is 33-35% and around.

In the current polyacrylate fiber production methods, flame and thermal resistance properties and performance are obtained by bonding metal ion salts with metal complex bond, which is one of the process steps that make up the process, and it has negativities such as low amount of toxic gas and smoke release after combustion and high carbonization in the product, pulling on the fiber, and not being able to maintain product form integrity with shrinkage.

The invention with patent number WO 2008/128660 A1 relates to the production method for the production of low-toxic and smoke-emission, uniformly dyed fireproof polyacrylate fibers. Zinc polyacrylate fiber is obtained by the hydrolysis of 4.5% (w/w) hydrazine-bonded acrylic fiber at 15% hydrazine concentration (0.85 chemical-fiber ratio), the hydrolysis of nitrile groups at 5% caustic concentration (0.28 chemical-fiber ratio), neutralization with 6% acetic acid (0.28 chemical-fiber ratio) and then adjusting 0.4% acetic acid with 7.4% zinc acetate salt (0.43 chemical: fiber ratio) to form a metal salt complex. The invention has achieved 37.5 LOI non-flammability performance in the fiber obtained by the use of a hydrazine crosslinker and the formation of a zinc acetate complex.

The invention with patent number CN105986474 A relates to obtaining high-temperature resistant and flame-retardant polyacrylate fibers. Regarding the production method in the said invention; it is subjected to the crosslinking process with hydrazine under a pressure of 0.3-0.4 MPa, in a two-stage independent hydrazine solution in the temperature range of 80- 120°C, in the concentration range of 7%-20% by weight for 3-7 hours. The obtained fibers are hydrolyzed with an aqueous alkaline solution in the temperature range of 70-110°C at a concentration in the range of 3%-10% by weight for 1-4 hours. The washed fibers were subjected to complexation processes with metal salts at a concentration of 3%-10% by weight for 1-4 hours in the temperature range of 80-120°C and then dried. At least one of copper sulfate, zinc sulfate, calcium sulfate, copper chloride, zinc chloride, calcium chloride, copper nitrate, zinc nitrate, or calcium nitrate is used as a metal salt. By applying the production methods mentioned in the invention, it is possible to obtain polyacrylate fibers with flame retardant performances of M1 and LOI values in the range of 40%-45%. Said invention has been used to increase the degree of crosslinking of said two-stage hydrazine process application, and its use in an application twice for 1-2 hours at a concentration of 7- 10% reveals some disadvantages:

Excessively high cross-linking will result in more brittle and stiff physical properties in fiber properties, which will bring technical limitations in the transformation of textile products and products and will cause a loss of desired quality and performance.

In production, a discontinuous and multi-stage process creates constraints in industrial production with low production capacity, high cost, and lower production speed.

- The use of hydrazine twice in the process at high concentrations and over long periods of time has the potential to generate more emissions during these processes with the need for high safety and process control. The chemical corrosive effect, carcinogenic risk, skin itchy sensitive effect, as well as aqueous toxic effect and strong reduction pose environmental threats. It reveals the risks of process and operation together with its potential excessive explosion and flammable properties.

In the invention US3997515, the polyacrylate fiber relates to flame resistant and/or flameretardant performance and combustion behaviors, light stability, and fiber performances in the use of different crosslinkers and metal salts after four-step processes of different copolymers. Accordingly, the following processes are applied in the invention, respectively;

It is realized at a concentration of 10%-40% of acrylonitrile-vinyl acetate copolymer with hydrazine and hydroxyl amine crosslinkers, at a chemical solution: fiber flotte ratio of 1 :10, 1 :20, 1 :20, at a temperature of 90-100°C, in the range of 1 -3 H.

- The hydrolysis process step is carried out at a concentration of 5-10% sodium hydroxide, chemical solution: fiber flotte ratio of 1 :10 and 1 :20, the temperature of 90- 100°C, in the range of 1 -3 H.

In the neutralization process step, 1 N hydrochloride from the mineral acids and sulfuric acid are applied with a combined process after caustic and then treated with acid.

In the complexation process step, polyvalent metal complex formation processes are carried out in acetate salts of calcium, magnesium, manganese, zinc, copper, iron, and aluminum metals at a concentration of 5-10%, chemical solution: fiber flotte ratio of 1 :10 and 1 :20, temperature range of 70-100 C and in the range of 0.5-3 H.

In the present art, polyacrylate fibers are produced in a discrete and four-step chemical process with complex reaction mechanisms, difficult process conditions, and discontinuous inefficient production methods. The low textile ability features together with the desired combustibility characteristics reveal results other than the features of the characteristic. In the production of functional textile products, it has become a must for the related technical field to get rid of the constraints and disadvantages of the conditions and parameters that make up the process by choosing the appropriate crosslinker and metal salt for the production of polyacrylate fiber in a continuous process in an efficient and effective industrial production method.

BRIEF DESCRIPTION OF THE INVENTION

The subject matter of the present invention relates to a high flame and combustion-resistant polyacrylate fiber and a method for its production.

The object of the invention is to present a method for the production of polyacrylate fibers with LOI values of 34% and above, and also to obtain polyacrylate with high combustion and flame resistance properties, as well as to set forth a production method in which negativities such as toxicity after combustion, toxic gas release and high carbonation in the product and inability to maintain integrity are eliminated. DETAILED DESCRIPTION OF THE INVENTION

The present invention is intended to present a continuous method suitable for sustainable industrial production in which polyacrylate fibers present properties, performances, and functions are accompanied by high resistance to flame and combustion, post-combustion toxicity with LOI values of 34% and above, release of toxic gasses and negativities such as high carbonation and failure to maintain integrity in the product. In the production of functional textile products, it has become a must for the related technical field to get rid of the constraints and disadvantages of a sustainable approach by choosing the appropriate crosslinking and metal salt in a continuous process in an efficient and effective industrial production method.

In the invention, development, and optimization processes are performed in all of the process steps for the production of a polyacrylate fiber with high efficiency and in which the existing disadvantages are eliminated. Accordingly, the production method of the invention comprises the following process steps: i. The selection of the appropriate multi-amine functional chemical for chemical crosslinking of the polymer chains forming the fiber and determining the environmental conditions, ii. Functional efficient and complete conversion of acrylate (-COO-M +) by the reaction of metal alkali salt hydrolysis of Nitrile groups not subjected to crosslinking of the polymer forming the fiber, iii. Neutralization of acrylate chemical group on the fiber forming polymer with acid after alkali hydrolysis, carboxylic acid conversion rate and chemical condition parameters, iv. The selection of metal salt suitable for the polyvalent metal complex formation of the carboxylic acid chemical groups of the polymer forming the fiber, as well as the conditions that form the metal ions and the determination of the necessary parameters to bind to the fiber directly affect the flammability properties and performances.

In the production method process step i) of the invention, it is ensured that the polymer nitrile (-CN) groups forming acrylic fibers are crosslinked with the functional groups within the crosslinking chemical compounds and retain their fiber form and properties in the subsequent reaction stages. The hydrazine compound can be used as a crosslinker in the production method process step i) of the invention.

As is in the state of the art, hydrazine is a chemical substance that is corrosive, irritating, biological (carcinogenic, skin corrosion and sensitization) harmful and toxic to aqueous solution, a strong reducing agent and its anhydrous form has extremely explosive environmental effects. For this reason, multi-amine compounds with at least two or more than 3, 4, 5, or more than 5 amine chemical functional groups in primary or secondary structure can be used as crosslinkers to eliminate the negative effects of the hydrazine chemical compound.

The crosslinker preferably comprises at least one amine functional group within it. Said crosslinker may be tertiary in structure provided that it contains at least two amine groups or at least two amine groups with at least two or more than 3, 4, 5, or more than 5 amine chemical functional groups, each amine group may be primary, secondary, tertiary chemical structure, or at least two amine groups with at least two primary or secondary structure. Other chemical structures may include more than two secondary amine groups, or 3, 4, or 5, as well as two or more amine groups, each of which is primary or secondary. The multiamine has a 2HN-R-NH₂ structure, R may be an alkyl group or an aryl group or may comprise more than one of a heteroaryl group. In some chemical structures, the alkyl, aryl, or heteroalkyl group may be straight-chain or branched, or cyclic or have more than one of these structures. The R groups are ether, diethers and polyether (((CH₂CH2)O)n(CH₂CH2) and n=1 , 2, 3, 4, 5 or more, polyethoethers ((CH₂CR2)S)O(CH₂CH2) n= 1 , 2, 3, 4, 5 or more, polyamines (CH₂CH₂)NX )n(CH₂CH₂), each X being independently H or alkyl or aryl or another suitable group and n= 1 , 2, 3, 4, 5 or more. The R groups can be dyes having a chemical group that absorbs light in the visible range (400-700 nm) to give the fiber a desired color. R groups may also be selected as flame retardant or flame-retardant phosphorus chemical functional groups. These may be groups containing trialkylphosphine, trialkylphosphite, trialkylphosphate, trialkylphosphonate, trialkylphosphoramide, hexaalkylcyclotripolyphosphazine or another phosphorus.

The polyacrylate production method of the invention may comprise chemical compounds having the following formulas as crosslinkers:

NH₂-(CH₂)n-NH₂, wherein said n is one of the values 0, 2, 4, 6, 8, NH2-(CH2)n-NH-(CH2)n-NH-(CH2)n-NH2, wherein said n value is one of the values 0, 2, 4, 6, 8,

NH2-(CH2)n-N-(-(CH2)n-NH2))(cH2)n-NH2, wherein said is one of the values 0, 2, 4, 6, 8,

NH2-(CH2)n-R-(CH2)n-NH-(CH2)n-NH2, wherein said n is one of the values 0, 2, 4, 6, 8, while R comprises one of the groups CH, C.

In the production method of the invention, at least one crosslinker comprising the amine functional group can be used as a crosslinker.

Multiple chemical compounds may be used as crosslinkers in the production method of the invention. At least one of the crosslinkers that may be used in the present invention is a chemical compound containing an amine group.

There is preferably a use of a crosslinker in the invention and said crosslinker comprises at least one amine group.

The preferred embodiment of the invention is that the crosslinker to be used as the crosslinker in the production step i) comprises more than one amine functional group within it. The crosslinker may contain 2, 3, 4 or 5 amine groups.

The most particular embodiment of the invention may include at least one, in certain proportions mixtures of hydrazine, hexamethylenediamine, diethylene triamine, tetraethylene triamine, tetraethylene pentamine, Bis-hexamethylene diamine, tris(2-aminoethyl)amine compounds, or all of them as crosslinkers.

The crosslinking process in process step i) is carried out under reflux conditions at boiling temperature. The temperature of said process is in the range of 100°C to 110°C. Said process temperature is preferably one of 100°C, 105°C, 105°C, 106°C, 107°C, 108°C, 109°C, and 1 10°C.

In the crosslinking process referred to in process step i), the crosslinker:acrylic fiber ratio is preferably one of 1 :1 , 1 :25, 1 :50, 1 :100, 1 :200, 1 :300 by weight.

The crosslinker in the process step i) is used to form a solution in at least one solvent. The amine group capable of solvent crosslinking may be an organic solvent. The solvent contains at least one of the organic solvents, water, methanol, ethanol, isopropanol, acetone, dimethylsulfoxide, dimethylformamide, dimethylacetamide. Water is present as said solvent, preferably there is at least one organic solvent in the water. Preferably, there is at least one organic solvent dissolved in water in the range of 10 to 70% by weight. In the most preferred embodiment, only water is present as the solvent. The crosslinker used in process step i) is preferably contained in the solvent at a value in the range of 20% to 60% by weight. Preferably, the crosslinker:solvent ratio is preferably in the range of 35 to 50% by weight.

In process step i), the crosslinker-fiber process medium is preferably stirred. Said mixing is preferably in the range of 100 to 500 rpm. Preferably, the mixing process is in the range of 200 rpm to 400 rpm.

The reaction time of the process step i) takes place in the range of 10 minutes to 90 minutes. The reaction time of process step i) is in the range of 15 minutes to 30 minutes according to the applied reaction parameters.

As is in the state of the art, in the process step ii), as a result of the process step i) crosslinking processes, the polymer nitrile (-CN) groups forming the uncrosslinked acrylic fiber perform the conversion of the nitrile groups to the CONH2, COOM functional groups with two-stage adhesion and elimination reactions in the presence of metal alkali. The process step ii) mainly consists of two-stage reactions with adhesion and hydrolysis reaction mechanisms. Said process step ii) is carried out under reaction conditions under boiling conditions. Preferably, process step ii) is performed at a value in the temperature range of 100 to 110°C.

The reactions referred to in process step ii) are preferably carried out by mixing with at least one mixer. Said mixing is preferably carried out in the range of 200 to 400 rpm.

The metal alkali salt referred to in the process step ii) is at least one of the compounds of calcium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide, calcium nitrate, magnesium nitrate, potassium nitrate, sodium nitrate.

The metal alkali salt used in the process step ii) is in the range of 8% to 20% by weight in at least one solvent. At least one of water, methanol, ethanol, isopropanol, solvents can be used as the solvent mentioned herein. Water is used as said solvent, if preferred, at least one organic solvent may be present in the water. Preferably, there is at least one solvent dissolved in water in the range of 10 to 50% by weight. Water is included as a solvent in the most preferred embodiment. The processing step ii) is preferably carried out over a time period of 10 to 30 minutes.

The amount of the metal alkali salt in the process step ii) is preferably one of 1 :1 , 1 :10, 1 :25, 1 :50, 1 :100, wherein metal alkali salt:f iber by weight.

Preferably, at least one acid is used for the neutralization process in the process step iii). Preferably, the pH of the acid to be used is preferably 3 or less.

If preferred, the acid may be a mixture. At least one of said acid mixtures is organic acid. Preferably, the organic acid in the acid mixture is at least 50% by weight.

As acid in the process step iii) comprises at least one of the group propionic acid, acetic acid, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, phosphoric acid, benzoic acid, nitric acid.

Preferably, an acid is used as the acid in the neutralization process.

The concentration of acid preferably used in the neutralization process is in the range of 10 to 20% by weight.

The neutralization process is carried out at a value in the range of temperatures of 40°C to 60°C. Preferably, the neutralization process is carried out at one of the temperatures of 45°C, 50°C, 55°C and 60°C.

Chlorides, acetates, sulfates, phosphates, carbonates of metals with an ion value of +2 or +3 and included in the 4th and 5th periods of the periodic table can be used as metal salts in the process step iv). Preferably, the salt of more than one metal may be used as the metal salt.

At least one of the chlorides, acetates, nitrates, or carbonates of the metals preferably having an ion value of +2 and +3 is used as the metal salt in the process step iv).

Preferably, at least one of zinc acetate, zinc chloride, zinc sulfate, magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium acetate, calcium acetate, calcium chloride, calcium nitrate, calcium sulfate, aluminum sulfate, copper nitrate, copper sulfate, copper chloride, copper acetate salts is used as metal salt in step iv). io In the production method process step iv) of the invention, aluminum sulfate or zinc chloride or mixtures thereof are used as metal salt in the most preferred application.

In the process step iv), the metal salt is used at a value in the range of 8% to 40% by weight.

In the invention, process step iv) is performed at a value in the range of 90 to 100°C temperatures.

In the invention, process step iv) is performed at a value in the range of 15 to 30 minutes.

The application of the production process steps disclosed in the invention enables the production of polyacrylate fibers in a period of 60 minutes to 120 minutes.

In the present invention, fibers of different performance and character were obtained as a result of processing acrylic fibers with a four-stage chemical process. In the second chemical process step, two functional amine crosslinking hydrazine and 1 ,6-hexamethylenediamine with different chemical structure and in the fourth chemical process step, superior performance, and properties of polyacrylate fibers with different metal zinc, magnesium, calcium, aluminum and copper salts and suitable process conditions and parameters were developed.

In the production method of the invention, the selection of the appropriate metal salt results in the contributions specified for the relevant technical field:

• Producing polyacrylate fibers with suitable non-flammable performance and properties,

• Using crosslinker and metal salt suitable for health, safety, and environment

• Decreasing energy consumption,

• Reducing the need for personnel,

• Reducing the carbon and water footprint during production,

With a more sustainable and environmentally friendly approach on an industrial scale, it is aimed to obtain polyacrylate fibers with low unit cost and non-flammable performance and properties.

In the current production methods, boiler paints are produced for approximately 9 hours at folate ratios of 1 :4 to 1 :6, and for the production of 1 ton of fiber, approximately 5 tons of water are used for each process step, resulting in total water consumption of 25 tons. In addition, with the addition of the washing process steps, this value approaches 30 tons. Unfortunately, these amounts of water used in the production methods in the current art cannot be recycled and are disposed of as waste. The present invention theoretically does not consume water except for a quantity of water evaporated by the moisture and process loss-leakages of the fiber tow belt in the continuous production system, and the production is carried out by chemical addition as the chemical is consumed. In the current production methods, it is seen that the polyacrylate fiber, which is produced with 30 tons of water consumption, is made at 1 -2 tons of water consumption with the present invention.

The polymer forming the fiber is an acrylonitrile polymer, which may comprise monomer units in a polymer chemical structure (CR1R2-CR3CN)- also comprising nitrile-functional monomer units. Here, the structures R1, R2 and R3 may be H, alkyl (methyl, ethyl, propyl), aryl (phenyl). However, R1 and R2 can both be H, as well as R3, methyl, and H. These polymeric chemical structures (meth) may be acrylate, alkyl vinyl ether, or other types of comonomer units, or may be polyacrylonitrile and polymethacrylate, acrylonitrile-vinylester copolymer and acrylonitrile polymer mixtures formed by them. Acrylonitrile polymer can be a homopolymer, copolymer (terpolymer, block) or, in the case of a copolymer, 50%, 60%, 70%, 70%, 80%, 90% of the monomer units can have the above-mentioned chemical (CR1 R2-CR3CN)- structure.

The fibers developed by the present invention production technology might be short fibers (e.g., about 1 mm to about 1 cm long) or might be in the form of long fibers (e.g., about 1 cm to about 1 m or longer). At the same time, the diameter of the fiber may be between approximately 0.7-50 dtex. If the diameter of the thin fibers in the fiber is <3 dtex, they can facilitate the penetration of chemicals into the fiber and polymer during crosslinking, hydrolysis, neutralization, metal complex bonding, If the diameter of the thick fibers in the fiber is >7 dtex, chemical reactions can occur in an inhomogeneous manner in the entire fiber. However, the small size of the pore structure of the fiber, the crystalline structure and degree of the polymer forming the fiber, the orientation of the polymer chains may facilitate or make it difficult to penetrate the chemical processes that take place at each stage, depending on whether they are more or less. In fact, core-shell structures can be formed by polymer modification formed close to the outer layer of the fibers. In such cases, it is obtained by modification with the outer layer properties of the obtained fibers and fibers, and the modified fiber can provide flame and heat resistant, antifungal, or antimicrobial performance, low heat transfer coefficient, high thermal insulation and hygroscopic properties, pH balance buffer feature and performance against acidic and basic. The polyacrylate fibers may be obtained from the acrylic fibers' hole, yarn, filament yarn, woven-nonwoven fabrics and from the mixture of at least one, two or more, as may be obtained from the different forms of staple fibers, tows, tops, bumps. Further, in textile applications of acrylic, the fabric may be a piece of clothing, e.g., a sock or an underwear or an upper garment, a blanket, e.g., a fire blanket, a curtain, a fibrous mat, a rug, a carpet.

Polyacrylate fiber can be produced starting from the form of acrylic fiber prepared with appropriate heat, light, stabilizer, antimicrobial, antiviral, anti-odor, biocidal additives, conductivity enhancers, antioxidants, pigments, plasticizers, and some antifungal additives. This can be accomplished by known methods, e.g., dissolving the polymer in a solvent, combining the solution with the additive, producing the fiber by wet gravity technology. The obtained fibers were obtained from polyacrylate fibers with the production technology detailed in the invention. The polyacrylate obtained may be in the form of fibers, yarns, fabrics. The products obtained from this can be used in many application areas in the textile sector, such as protective clothing, public transport textile products, filtration, fireproof blanket, upholstery, clothing (socks, underwear), outdoor and indoor textile applications, etc.

The polyacrylate fibers can be prepared by mixing with one or two or more of the appropriate solutions of heat, light, stabilizer, antimicrobial, antiviral, anti-odor, biocidal additives, conductivity enhancers, antioxidants, pigments, plasticizers, and some antifungal additives in the metal complex step, which is the last step of the known process steps and can be produced by drying or fixing the fibers by a heat treatment. This can be accomplished by known methods, dissolving the additives in a suitable solvent, combining the solution with the additive, and producing the fiber by wet gravity technology. The obtained fibers were obtained from polyacrylate fibers with the production technology detailed in the invention. The polyacrylate obtained may be in the form of fibers, yarns, fabrics. Protective clothing, public transport textile products, filtration, fireproof blankets, upholstery, clothing (socks, underwear), outdoor and indoor textile products can be obtained from the polyacrylate fibers obtained.

Additional chemical compounds may be used during the production of the polyacrylate fibers of the invention to increase the chemical and physical properties of the polyacrylate fibers to be obtained, such as non-flammability, strength, and humidity.

As is known from the invention with patent number JP 5056358, the dyeing processes of polyacrylate fibers can be carried out with cationic dyeing systems due to the carboxylate and carboxylic acid chemical functional groups they have, but the desired technical characteristics are not provided in the dyeing fastness and industrial applications of polyacrylate fibers after the processes performed in this way. It has been determined by the present inventors that polyacrylate fiber, reagent, and pigment dyeing systems can demonstrate superior performances in applicability and dyeing fastness.

Tests

For the production of polyacrylate fibers, the process steps in the state of the art are applied. These process steps are as follows: i. Performing crosslinking of acrylic fibers with at least one crosslinker, ii. Subjecting acrylic fiber fibers subjected to a crosslinking process to hydrolysis reaction with at least one metal alkali salt, iii. Subjecting the fibers to neutralization reactions with at least one acid after the process step ii). iv. Complexing of the fibers obtained as a result of the neutralization process with the use of at least one metal salt or mixtures of more than one metal salt

In said process steps, the non-flammability properties, and characters of the acrylic fiber in which different crosslinking and metal salts were applied in the present invention subject, process steps i) and iv) were analyzed. The results obtained are shared under this heading.

HMDA solution was used together with hydrazine in the tests as a crosslinker in the process step i).

Hydrazine and HMDA were used for fiber crosslinking, and NIR spectroscopy was performed on the concentrations of the solutions. In the solution, 0-100% reference solutions with known concentration were prepared for analysis and spectroscopic calibration was prepared and the calibration correlation was found to be R2=98-99. This method was used in the analysis of the main charge solution and washing waters after the application.

The process step of crosslinking of acrylic fibers with Hydrazine and HMDA solution

Hydrazine and HMDA chemical compounds are used as crosslinkers for 30 g of acrylic fiber to investigate the relationship between different crosslinking in acrylic fiber and flammability properties and performances. Said crosslinking operations have been carried out in a 200- rpm mixing and 107°C temperature environment. After each process step, the fiber was washed with water and the chemical residues were removed and dried overnight in the oven at a temperature of 60°C. Afterwards, the fiber was weighed and the amount of crosslinking in the fiber was determined by gravimetric calculations. It was calculated from the analysis that it formed a crosslink at the rate of 70-75% (w/w) in HMDA-applied fiber at the rate of 4.5- 5% (w/w) in hydrazine-applied fiber.

Hydrolysis of acrylic fibers subjected to hydrazine and HMDA crosslinking with metal alkali salt

The reaction processes of hydrazine and HMDA crosslinked 30 g fibers were carried out at a concentration of 16% sodium hydroxide, 200 rpm stirring at a temperature of 105°C. The hydrolysis mechanism is realized in two stages, the first stage is understood by dark red color transformation, while the second stage is determined by the complete light-yellow color of the fiber color. The completion of the reaction at this stage was detected by the time completing the two-color transformation. The obtained fiber was washed with warm water after each process step and its chemical residues were removed and dried overnight under 60°C temperature incubator conditions.

In the test studies, the metal alkali salt was converted to sodium carboxylate form by the caustic chemical transformation of the functional Nitrile and acetate groups in the acrylic fiber at a concentration of 16% in the solution.

Neutralization of Sodium Polyacrylate fibers with acid

Neutralization of hydrazine and HMDA crosslinked fibers with acetic acid, whose polyacrylate conversion from acrylic fibers was completed, was performed at a concentration of 20%, at a mixing environment of 200 rpm, at a temperature of 56°C, with acetic acid, which is a weak organic acid. Neutralization of the fiber is determined by monitoring the peak of the COONa chemical functional group at a wide and widespread wavelength of 2900-3600 cm'¹ with FT- IR spectroscopy. The obtained fiber was washed with water and the acid chemical residues were removed and dried overnight under 60°C temperature incubator conditions and examined with FT-IR.

In the neutralization test study, it was analyzed that 20% acetic acid concentration in the solution, sodium polyacrylate groups were chemically converted into carboxylic acid form by neutralization and the desired physical properties of the fiber were appropriate in the next stage. Investigation of complex formation with metal salt in fibers obtained after neutralization

In hydrazine and HMDA crosslinked fibers, fibers are obtained by forming a polyvalent bond in complexes with different metal ions with the chemical group of carboxylic acid after neutralization with acid. In this step, different metal-organic and inorganic salts; zinc acetate, zinc chloride, zinc sulfate, magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium acetate, calcium acetate, calcium chloride, calcium nitrate, calcium sulfate, aluminum sulfate, copper nitrate, copper sulfate, copper chloride, copper acetate were added to the water and acid to increase ionization at different concentrations specified in Table 3, creating metal ion-chelate complex coordination bonds and binding to the polymer at 200- rpm mixing speed, at a temperature of 90°C, adjusting the solution to the pH range of 4.5-5 in the presence of weak acid. The obtained fiber was washed with water and removed from excess metal and opposite ions and examined by drying at 60°C incubator temperature.

Table 1. Conditions and parameters of the complexation reaction of metal salts

In the test runs, different concentrations of metal salt were used (Table 1) and the nonflammability properties and characteristics of the fibers were found suitable for detailed examination at 20 wt% metal salt concentration values in the solution. The physical test analysis of the obtained fibers were completed and given in Table 2. Table 2. Results of physical tests and analysis of the obtained fibers

In the flammability tests and analyses performed on the prepared polyacrylate fibers, the fibers were generally obtained in pink color when hydrazine was used as a crosslinker and different metal salts were applied, and the fibers were obtained in white color when different metal salts were applied as HMDA crosslinkers. However, the non-flammability performances, behaviors, and characteristics of the polyacrylate fibers obtained with different crosslinking and metal salts in the study are given in Table 2 and Table 3 in detail. Non- flammability performances, behaviors, and characters were examined according to the minimum amount of oxygen required for the combustion of the fiber (LOI index), flame retention and combustion continuity, glare formation with the flame onset and flame-free progression, as well as the carbonization form of the fiber after flame and combustion, shrinkage, shrinkage, melting, and evaluations were made according to gas output and formation during and after flame retention and combustion.

Table 3. Flammability tests and evaluation of the obtained fibers

When different metal salts were used in the preparation of polyacrylate fibers, the density of the fibers in the presence of zinc salts was found to be 1 .6 g/cm³, while the densities of other metal salts were found to be around 1 .4 g/cm³.

In the preparation of polyacrylate fibers, other metal salts of non-flammability performance and character in fibers prepared using zinc and aluminum inorganic salts: zinc acetate, zinc chloride, zinc sulfate, magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium acetate, calcium acetate, calcium chloride, calcium nitrate, calcium sulfate, aluminum sulfate, copper nitrate, copper sulfate, copper chloride, copper acetate showed higher performance results than the polyacrylate fibers prepared in the presence of.

According to Table 2 and Table 3, the most possible embodiment of the invention is the polyacrylate fiber products with high LOI values obtained as a result of the production of polyacrylate fiber, in which the HMDA chemical compound is used as a crosslinker in the process step i), and in which zinc chloride and aluminum sulfate compounds are used as metal salt in the process step iv).

According to Table 2 and Table 3, the most possible embodiment of the invention is the polyacrylate fiber products with high LOI values obtained as a result of the production of polyacrylate fiber, in which the hydrazine chemical compound is used as a crosslinker in the process step i), and in which zinc chloride and aluminum sulfate compounds are used as metal salt in the process step iv).

Claims

CLAIMS The invention relates to a production method for obtaining polyacrylate fibers having LOI values of 34% and above, comprising the following process steps, wherein the process environment conditions and parameters are optimized: i. Crosslinking of acrylic fibers with at least one crosslinker,

One crosslinker being hydrazine or containing at least two amine functional groups in it or a mixture thereof, ii. Subjecting acrylic fiber fibers subjected to crosslinking process to hydrolysis reactions with at least one metal alkali salt solution,

- Said at least one metal salt being in the range of 8% to 20% by weight in the solution, iii. Subjecting the fibers to neutralization reactions with at least one acid after the process step ii),

- Said acid being in the range of 10-20% by weight in the solution,

- Said acid being one of the acids with a pH value of 3 or less, iv. Complexing of the fibers obtained as a result of the neutralization process with the use of at least one metal salt or mixtures of more than one metal salt

Using one of the compounds of the metal salt mentioned herein, zinc acetate, zinc chloride, zinc sulfate, magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium acetate, calcium acetate, calcium chloride, calcium nitrate, calcium sulfate, aluminum sulfate, copper nitrate, copper sulfate, copper chloride, copper acetate,

- Said at least one metal salt being in the range of 8% to 20% by weight in the solution,

Performing the process step at a value in the range of 90°C to 100°C temperatures,

- Acrylic fiber:metal salt ratio being in the range of 1 :1 to 1 :150.

2. A production method according to Claim 1 , characterized in that each of the process steps i-iv) is carried out in a separate bath or reactors, or in that the process steps ii), iii), iv) are carried out in a separate sequential and sequential bath or reactor in a continuous manner, as the process step i) can be carried out in a separate bath or reactor.

3. A production method according to Claim 1 , characterized in that the process steps i- iv) are performed in series and sequential manner in a bath or reactor.

4. A production method according to any of the preceding claims, characterized in that the tow band has a value in the range of 0.01 m/min to 10 m/min in case of application of continuous production process steps.

5. A production method according to one of the preceding claims, characterized in that it is subjected to washing processes before, after, or during application of the processes i-iv).

6. A production method according to one of the preceding claims, characterized in that, as crosslinkers in process step i), it comprises at least one of the following compounds:

NH₂-(CH₂)_n-NH₂, wherein said n is one of the values 0, 2, 4, 6, 8, NH₂-(CH₂)_n-NH-(CH₂)_n-NH-(CH₂)_n-NH₂, wherein said n is one of the values 0, 2, 4, 6, 8,

- NH₂-(CH₂)_n-N-(-(CH₂)_n-NH₂))(CH₂)n-NH₂, wherein said n is one of the values 0, 2, 4, 6, 8,

- NH₂-(CH₂)_n-R-(CH₂)_n-NH-(CH₂)n-NH₂, wherein said n is one of the values 0, 2, 4, 6, 8, while R is one of the groups CH, C.

7. A production method according to one of the preceding claims, characterized in that the crosslinker comprises at least one of hexamethylene diamine, diethylene triamine, tetraethylene triamine, tetraethylene pentamine, bis-hexamethylene diamine, tris(2- aminoethyl)amine compounds in the process step i).

8. A production method according to one of the preceding claims, characterized in that in the process step i) the crosslinker is dissolved in at least one solution, said solvent being at least one of water, methanol, ethanol, isopropanol compounds. A production method according to Claim 8, characterized in that said solvent in process step i) is water, the concentration of the crosslinker in water is in the range of 35% to 50% by weight. A production method according to Claim 1 , characterized in that the temperature of the process step i) is one of 100°C, 105°C, 106°C, 107°C, 108°C, 109°C and 110°C. A production method according to Claim 1 , characterized in that the metal alkali salt in the process step ii) is at least one of the following compounds: calcium hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide, calcium nitrate, magnesium nitrate, potassium nitrate, sodium nitrate. A production method according to Claim 1 , characterized in that said solvent in the process step ii) is at least one of the organic solvents of water, methanol, ethanol, isopropanol. A production method according to Claim 1 , characterized in that said acid in the process step iii) is at least one of the group propionic acid, acetic acid, sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, phosphoric acid, benzoic acid, nitric acid. A production method according to Claim 1 , characterized in that the process step iii) is carried out at one of the temperatures of 45°C, 50°C, 55°C and 60°C. A production method according to Claim 1 , characterized in that the metal salt said in the process step iv) is at least one of or mixtures of zinc chloride, aluminum chloride, zinc sulfate or aluminum inorganic salt compounds or mixtures thereof. Polyacrylate fibers or filaments obtained by the production method according to one of the preceding claims. A polyacrylate fiber or filament according to Claim 16, having antibacterial, antiviral, antifungal, anti-odor properties for use in the production of yarn fabric, garment piece, socks, underwear or upper garment, blanket, fire blanket, curtain, fiber mat, rug, or carpet, either alone or in a fiber mixture comprising at least one of cotton, cellulose, polyester, nylon. A polyacrylate fiber or filament according to Claim 17, having moisture and water vapor adsorbing and, accordingly, heat-generating properties, for use in the production of yarn fabric, garment piece, socks, underwear, or upper garment, either alone or in a fiber mixture comprising at least one of cotton, cellulose, polyester, nylon. The use of a polyacrylate fiber or filaments characterized in claims 16-18, alone or as part of a fiber mixture comprising at least one of cotton, cellulose, polyester, nylon, for the production of yarn fabric, garment piece, socks, underwear or upper garment, blanket, fire blanket, curtain, fiber mat, rug, or carpet.