JP2024147302A - Flame retardant for polyester fibers - Google Patents

Abstract

To provide a flame retardant processing agent for a polyester-based fiber which can provide flame retardancy equivalent to or better than that of an aliphatic cyclic phosphonic acid ester.SOLUTION: There is provided a flame retardant processing agent for a polyester-based fiber in which phosphorus-containing cations and phosphorus-containing anions are contained in an aqueous solvent, wherein (a) the phosphorus-containing cation is a phosphonium cation represented by the formula A [P(R1R2R3R4)] (wherein, R1 to R4 are identical or different from each other and represent an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 1 to 6 carbon atoms) and (b) the phosphorus-containing anion is an anion having a group represented by the formula B [(R5)(R6)P(=O)-] (wherein, R5 to R6 are identical or different from each other and represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 8 carbon atoms or a linear or branched alkoxy group having 1 to 8 carbon atoms).SELECTED DRAWING: None

Description

The present invention relates to a novel flame retardant for polyester fibers. More specifically, the present invention relates to a flame retardant for post-processing polyester fibers.

Polyester fiber products used for various purposes, including interior items such as curtains and carpets, are often treated with flame retardant coatings, and some products are required to meet national flame retardancy standards.

As a post-processing flame-retardant treatment for polyester fibers, a method of padding the fibers with an aqueous solution of a phosphorus compound, such as guanidine phosphate, has been used for some time.

However, the above-mentioned padding process has the drawback that the resulting flame-retardant fiber is not water resistant, and the agent is washed away by rinsing with water, resulting in the loss of flame retardancy. In addition, measures are required to address problems such as whitening caused by crystal growth of the flame retardant on the fiber surface, as well as stickiness caused by the deliquescence of the flame retardant, which results in poor appearance.

One method that can solve these problems is the so-called durable flame retardant processing. Known durable flame retardant processing methods include exhaustion processing and thermosol processing.

In the exhaustion method, a flame retardant is added to the dyeing bath when dyeing fabric using a high-pressure jet dyeing machine, and flame retardant processing is performed at the same time as dyeing. No additional process is required for fabrics that require dyeing, and flame retardant processing with durability (water resistance and dry cleaning resistance) is possible, making this a flame retardant processing method for polyester fibers that is used in a wide range of fields.

Thermosol processing is a method of dyeing polyester fibers with disperse dyes by dry heat treatment, and is a historical continuous dyeing method developed by DuPont in the United States. The conditions of the thermosol processing method can also be used to impart durable flame retardancy to fibers. Thermosol processing makes it possible to penetrate flame retardants into the fibers by simply performing heat treatment and water washing in addition to the conventional padding process without using special equipment, making it easier to impart flame retardancy than exhaustion processing.

However, the flame retardants that can be used in exhaustion or thermosol processing are limited to certain compounds. This is because the flame retardants used in these processes must have the property of quickly penetrating, diffusing, and fixing in the relaxed, amorphous parts of the polyester during thermal processing.

Hexabromocyclododecane (HBCD), a halogen-based flame retardant that was once commonly used in this field, is persistent and highly accumulative, and there are concerns that it may have adverse effects on the human body and the environment. In Japan, it was designated as a Type 1 specified compound under the Act on the Examination and Regulation of Chemical Substances (Act on the Examination of Chemical Substances and Regulation of Their Manufacture, etc.) on October 4, 2013, making it virtually impossible to use in the country.

For this reason, in recent years, tris(2,3-dibromopropyl)isocyanurate (TBIC) has generally been used as a halogen-based flame retardant (see, for example, Patent Document 1). In contrast to this, phosphorus-based flame retardants have also come to be used in recent years (see, for example, Patent Document 2). For example, 2,4-diamino-2,4,6-triphenoxycyclotriphosphazene and 5,5-dimethyl-2-(2'-phenylphenoxy)-1,3,2-dioxaphosphorinane-2-oxide are known as phosphorus-based flame retardants. The reason why phosphorus-based flame retardants are used so frequently is thought to be that halogen-based flame retardants are themselves toxic, and there are concerns about the generation of dioxins during incineration, and various regulations are being implemented.

Usually, the flame retardants that can be used in exhaustion and thermosol processing are often the same, but phosphorus-based agents specialized for thermosol processing include aliphatic cyclic phosphonates such as (5-ethyl-2-methyl-2-oxide-1,3,2-dioxaphosphonaline-5-yl) methyl phosphonate and bis(5-ethyl-2-methyl-2-oxide-1,3,2-dioxaphosphonaline-5-yl) methyl phosphonate (see, for example, Patent Document 3 and Patent Document 4). These agents can be flame-retarded with excellent water resistance on polyester fibers by performing heat treatment at about 170°C or higher after padding processing. In addition, these agents are highly water-soluble and do not require an activator in the aqueous treatment solution, so there are no problems caused by the addition of an activator (reduced fastness, dye migration, etc.), and they can be said to be very excellent agents.

Patent Publication 2012-167411 Patent No. 6818327 JP 7-145562 A JP 7-42087 A Patent Publication No. 2021-54924 International Publication WO2014/2958

However, some of the above-mentioned aliphatic cyclic phosphonates are designated as precursors of chemical weapons under the so-called Chemical Weapons Prohibition Act (Act on the Prohibition of Chemical Weapons and the Control of Specified Chemicals (Act No. 65 of April 5, 1995)), and they must be handled and managed with care. For example, when manufacturing, using, or importing/exporting them, the actual quantity must be notified to the Minister of Economy, Trade and Industry, and depending on the amount handled, international inspections must be accepted, which is a lengthy administrative process, so they tend to be avoided.

Therefore, the main object of the present invention is to provide a flame retardant for polyester fibers that can provide flame retardancy equal to or greater than that of aliphatic cyclic phosphonic acid esters.

As a result of extensive research into the problems of the prior art, the inventors discovered that the above objectives could be achieved by adopting a composition that contains a specific resin component, and thus completed the present invention.

That is, the present invention relates to the following flame retardant for polyester fibers.
1. A flame retardant processing agent comprising a phosphorus-containing cation and a phosphorus-containing anion in an aqueous solvent,
(a) the phosphorus-containing cation is a phosphonium cation represented by the formula A[P(R ¹ R ² R ³ R ⁴ )] (wherein R ¹ to R ⁴ are the same or different and represent an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 1 to 6 carbon atoms), and (b) the phosphorus-containing anion is an anion having a group represented by the formula B[(R ⁵ )(R ⁶ )P(═O)—] (wherein R ⁵ to R ⁶ are the same or different and represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms);
A flame retardant processing agent for polyester fibers, characterized in that
2. The cation is represented by the following formula (1):
2. The flame retardant for polyester fiber according to claim 1, wherein R ¹ to R ⁴ are the same or different and each represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 1 to 6 carbon atoms.
3. The anion is
(A) Formula (2) below
(wherein R ⁵ to R ⁷ are the same or different and represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms), and (B) an anion containing a group represented by formula B[(R ⁵ )(R ⁶ )P(═O)-] (wherein R ⁵ to R ⁶ are the same or different and represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms) (excluding the anion (A) above).
2. The flame retardant for polyester fibers according to claim 1, wherein the flame retardant is at least one of the following:
4. The polyester-based flame retardant according to item 1, wherein the total amount of the phosphorus-containing cations and phosphorus-containing anions in the polyester-based flame retardant is 0.05 to 5.0% by weight.
5. The flame retardant processing agent for polyester according to the above item 1, which is used for imparting flame retardancy to polyester fibers by exhaustion processing or thermosol processing.
6. A flame-retardant polyester fiber, comprising the polyester fiber flame-retardant agent according to item 1.
7. The flame-retardant polyester fiber according to item 6, wherein the polyester fiber flame-retardant agent is contained in an amount of 0.01 to 0.5 parts by weight in terms of the total solid content of the cationic component and the anionic component per 100 parts by weight of the polyester fiber.

The present invention provides a flame retardant for polyester fibers that can provide flame retardancy equal to or greater than that of aliphatic cyclic phosphonic acid esters.

In particular, the flame retardant for polyester fibers contains a specific organic phosphonium salt compound, which not only provides higher flame retardant performance than conventional flame retardants, but also provides excellent flame retardancy at low concentrations, making it economically advantageous.

In addition, the flame retardant of the present invention is not likely to generate dioxin-like substances that are harmful to the human body when burned, and is not subject to strict legal restrictions such as the Chemical Weapons Prohibition Act, making it relatively easy to manage and handle.

1. Flame retardant for polyester fibers The flame retardant for polyester fibers of the present invention (the flame retardant for the present invention) is a flame retardant containing a phosphorus-containing cation and a phosphorus-containing anion in an aqueous solvent,
(a) the phosphorus-containing cation is a phosphonium cation (cation component) represented by the formula A[P(R ¹ R ² R ³ R ⁴ )] (wherein R ¹ to R ⁴ are the same or different and represent an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 1 to 6 carbon atoms), and (b) the phosphorus-containing anion is an anion (anion component) having a group represented by the formula B[(R ⁵ )(R ⁶ )P(═O)—] (wherein R ⁵ to R ⁶ are the same or different and represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms).
The present invention is characterized in that:

The flame retardant of the present invention is basically in the form of an aqueous solution, and it is preferable that the cationic and anionic components are dissolved in the aqueous solvent (ionized), but some precipitation is acceptable as long as the effect of the present invention is not hindered. The valence of the cationic and anionic components is not limited, and may be, for example, monovalent or polyvalent (2 or more). Furthermore, the flame retardant of the present invention may contain ionic components other than the cationic and anionic components as long as the effect of the present invention is not hindered, but it is more preferable to adopt a system that does not contain ionic components other than the cationic and anionic components.

In the present invention, compounds capable of supplying the above-mentioned cationic component (phosphorus-containing cation) and/or anionic component (phosphorus-containing anion) by dissolving in water are also listed below as the above-mentioned cationic component or anionic component. Therefore, compounds that dissolve in water to generate phosphate ions (phosphorus-containing anions), such as phosphoric acid, are also included. In addition, compounds that dissolve in water to supply both a phosphorus-containing cationic component and a phosphorus-containing anionic component, such as an organic phosphonium salt such as tributyl(methyl)phosphonium dimethylphosphate, can be used as the above-mentioned cationic component and anionic component. Such compounds are advantageous in that it is not necessary to prepare both a cationic component and an anionic component, and the flame retardant of the present invention can be prepared relatively easily.

The cationic component is a phosphonium cation represented by the formula A[P(R ¹ R ² R ³ R ⁴ )] (wherein R ¹ to R ⁴ may be the same or different and represent an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 1 to 6 carbon atoms).

As the above cation, for example, a cation represented by the following formula (1) can be suitably used: R ¹ to R ⁴ are the same as defined above.
The alkyl or alkenyl groups of R ¹ to R ⁴ may be either linear or branched. Examples of the alkyl group include an ethyl group, a methyl group, a propyl group, an isopropyl group, a butyl group, a s-butyl group, a t-butyl group, an isobutyl group, a propylene group, and a hexyl group. Examples of the alkenyl group include a vinyl group and an allyl group.

Specific examples of preferred cationic components in the present invention include tetrabutylphosphonium, methyltributylphosphonium, and ethyltributylphosphonium.

The anion component contains a group represented by formula B[(R ⁵ )(R ⁶ )P(═O)—] (wherein R ⁵ to R ⁶ are the same or different and represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms). The anion component may contain one or more groups represented by formula B.

The alkyl group may be either linear or branched. Examples include ethyl, methyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, propylene, hexyl, heptyl, and octyl groups.

The alkoxy group is one in which R ⁵ and R ⁶ are the same or different and are represented by -OR (R is an alkyl group having 1 to 8 carbon atoms). R may be either linear or branched. Examples of the alkoxy group include an ethyl group, a methyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a s-butyl group, a t-butyl group, a propylene group, a hexyl group, a heptyl group, and an octyl group.

Among these, at least one of the anionic components (A) and (B) below can be preferably used. That is, anionic phosphorus-containing compounds can be preferably used. These are compounds that can dissolve in water to supply phosphorus-containing anions such as phosphate ions. In other words, phosphorus-containing anions generated by dissolving the phosphorus-containing compound in water can be used as the anionic component. These can be publicly known or commercially available products.

(A) Formula (2) below
(wherein R ⁵ to R ⁷ are the same or different and represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms), and (B) anions containing a group represented by formula B[(R ⁵ )(R ⁶ )P(═O)-] (wherein R ⁵ to R ⁶ are the same or different and represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms) (excluding the anion (A) above).
At least one of the above can be suitably used.

Specific examples of (A) include at least one phosphorus-containing compound such as phosphoric acid, phosphorous acid, hypophosphorous acid, methylphosphonic acid, ethylphosphonic acid, butylphosphonic acid, n-octylphosphonic acid, bis(2-ethylhexyl)phosphate, dimethylphosphate, diethylphosphate, and dibutylphosphate.

Specific examples of (B) above include anions other than (A) above, such as at least one of etidronic acid, phytic acid, tripolyphosphate, [nitrilotris(methylene)]tris(phosphonic acid), 2-phosphonobutane-1,2,4-tricarboxylic acid, and N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid). As shown in these examples, chelating agents containing a group represented by the above formula B can be preferably used.

The etidronic acid is a compound represented by the following formula (3).

The phytic acid is a compound represented by the following formula (4).

The tripolyphosphoric acid is a compound represented by the following formula (5).

The above-mentioned [nitrilotris(methylene)]tris(phosphonic acid) is a compound represented by the following formula (6).

The 2-phosphonobutane-1,2,4-tricarboxylic acid is a compound represented by the following formula (7).

The above-mentioned N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid) is a compound represented by the following formula (8).

The aqueous solvent may be a) water, b) a mixed solution of water and a water-soluble organic solvent, or c) an aqueous solution in which a water-soluble solid substance is dissolved in water.

Examples of water-soluble organic solvents include monohydric alcohols such as ethanol, methanol, isopropyl alcohol, and butanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, 1,8-propanediol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 2,3-butylene glycol, neopentyl glycol, hexylene glycol, thiodiglycol, glycerin, trimethylolethane, trimethylolpropane, and diglycerin; and glycol ethers such as ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether (ethyl carbitol), and diethylene glycol monobutyl ether. These can be used alone or in combination of two or more.

Examples of water-soluble solid substances include various components (additives) that are blended into known flame retardant processing agents.

The content of the cationic component in the flame retardant of the present invention is not limited, but is usually about 0.01 to 10% by weight, preferably 0.05 to 5.0% by weight, and even more preferably 0.05 to 2.5% by weight.

The content of the anion component in the flame retardant of the present invention is not limited, but is usually about 0.01 to 10% by weight, preferably 0.05 to 5.0% by weight, and even more preferably 0.05 to 2.5% by weight.

The ratio of cationic components to anionic components in the flame retardant of the present invention is not particularly limited, but it is preferable that the chemical equivalence ratio of cationic components to anionic components is about 1:00.9 to 1.1.

The flame retardant of the present invention may contain other additives as long as they do not interfere with the effects of the present invention. Examples include preservatives, deodorants, thickeners, resin binders, sewability improvers, finishing agents, deodorants, fabric softeners, water repellents, oil repellents, crosslinking agents (isocyanate-based, ethyleneimine-based, glycidyl-based), etc. However, in the flame retardant of the present invention, the inclusion of a small amount (usually 0.1% by weight or less) of the aliphatic cyclic phosphonic acid ester, which is the flame retardant component, is permitted as long as it does not interfere with the effects of the present invention, but it is particularly preferable to keep it at 0% by weight.

The flame retardant agent of the present invention can be an aqueous solution containing a cationic component, an anionic component, and an aqueous solvent. Therefore, the flame retardant agent of the present invention can be suitably prepared, for example, by a method including a step of adding each of the components to an aqueous solvent and dissolving the cationic component and the anionic component in the aqueous solvent. In this case, the order of addition of each component is not particularly limited. In addition, mixing can be performed using a known or commercially available device such as a mixer or kneader.

The content of the cationic and anionic components in the flame retardant of the present invention may be adjusted to the concentration ranges shown above, but it may also be provided as a concentrated aqueous solution, for example, on the assumption that it will be diluted with water when in use.

2. Flame-retardant polyester fibers The types of polyester fibers to which the flame retardant of the present invention can be applied are not limited, and examples include fibers containing polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, etc.

Within the scope of the present invention, the flame retardant treatment agent of the present invention can treat a) fibers such as a mixture of polyester resin and other synthetic resins, or polymer alloys, or b) fibers blended with polyester fibers and other synthetic fibers or natural fibers (cotton, silk, hemp, etc.). The fiber form can be either short or long. The fiber diameter is not limited, and can be set to, for example, about 5 to 50 μm, but is not limited thereto.

In addition, in the present invention, in addition to the polyester-based fiber itself, the material may be a fabric (cloth, cloth) made of polyester-based fiber. The fabric may be either a woven fabric or a nonwoven fabric. In addition to a fabric made of a single polyester-based fiber, the fabric may be a fabric containing polyester-based fiber and other fibers (synthetic fibers or natural fibers). In the case of a fabric, the basis weight may be, for example, about 30 to 500 g/ ^m2 , but is not limited thereto.

In this way, polyester-based flame-retardant fibers containing the flame-retardant agent of the present invention are also included in the present invention by being flame-retarded by the flame-retardant agent of the present invention. In this case, the amount of the flame-retardant agent of the present invention applied to the polyester-based fiber can be appropriately set depending on, for example, the type of fiber and the desired flame retardancy, but it is usually about 0.05 to 5.0 parts by weight, and preferably 0.1 to 0.5 parts by weight, as the total solid content of the cationic component and the anionic component per 100 parts by weight of the polyester-based fiber. In this way, high flame retardancy can be obtained even with a relatively small amount applied, which is also advantageous in terms of production costs.

3. Method for producing flame-retardant polyester fiber The method for producing flame-retardant polyester fiber by flame-retarding polyester fiber using the flame-retardant processing agent of the present invention is not particularly limited, and can be carried out using known processing methods and processing equipment. For example, any of padding processing, backing processing, immersion processing, exhaust processing, spray processing, thermosol processing, gravure processing, etc. can be applied. Among these, the flame-retardant processed product of the present invention can be preferably applied to exhaust processing or thermosol processing.

It was generally believed that ionic water-soluble compounds such as the flame retardant components of the flame retardant processing agent of the present invention could not provide durable flame retardant processing for polyester fibers, even when subjected to exhaustion processing or thermosol processing. In this regard, the combination of specific cationic and anionic components (particularly organic phosphonium salts) in the present invention can diffuse the flame retardant components into polyester fibers even under such processing conditions, and the resulting flame retardancy can be said to be a performance that was previously unforeseen.

In particular, in the present invention, a method including (a) a step of padding polyester-based fibers with the flame retardant of the present invention (padding step) and (b) a step of curing under heat (curing step) can be preferably used as the thermosol processing.

In the padding process, polyester fibers are immersed in the flame retardant of the present invention and then squeezed. The padding process can be carried out according to a known padding method. It can also be carried out using a known or commercially available padding processing device. In the present invention, padding can be either a dry type or a wet type. The squeezing rate during squeezing is not limited, but can usually be set appropriately within the range of about 30 to 200%.

In the curing process, the polyester fiber containing the flame retardant of the present invention is heat-treated. The heat treatment conditions are, for example, in air at about 150 to 200°C, but are not limited thereto. The heat treatment time can be, for example, within a range of about 30 seconds to 10 minutes, but other times can also be set.

Prior to the curing process, preliminary drying can be carried out as necessary. The conditions for preliminary drying are not limited, but typically the heat treatment can be carried out in air at about 50 to 100°C, but are not limited to this. The heat treatment time can be within a range of, for example, 1 to 20 minutes, but other times can also be set.

After the curing process, if necessary, a cleaning process can be carried out to remove excess flame retardant, etc. The cleaning process can be carried out using warm water at, for example, about 40 to 80°C.

In this way, a flame-retardant polyester fiber containing the flame-retardant components (such as cationic and anionic components) of the flame retardant processing agent of the present invention can be obtained. In other words, a flame-retardant polyester fiber in which at least cationic and anionic components are attached to a polyester fiber can be provided.

The following examples and comparative examples are presented to more specifically explain the features of the present invention. However, the scope of the present invention is not limited to the examples. In the examples, "%" means "% by weight."

[Preparation Example A]
Flame retardant A was obtained by adding ion-exchanged water to 10 g of Hishicolin PX-4MP (manufactured by Nippon Chemical Industry Co., Ltd., tributyl(methyl)phosphonium dimethylphosphate) and diluting it to a solid content of 20%.

[Preparation Example B]
Ion-exchanged water was added to 10 g of tributyl(ethyl)phosphonium diethylphosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) and the mixture was diluted to a solid content of 20%, to obtain a flame retardant B.

[Preparation Example C]
10.367 g of a 40% aqueous solution of tetrabutylphosphonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in a beaker, and 3.153 g of dibutyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) was gradually added while stirring, and the mixture was further stirred at room temperature for 10 minutes. The resulting aqueous solution was diluted with ion-exchanged water to a solid content of 20%, to obtain a flame retardant processing agent C.

[Preparation Example D]
Flame retardant D was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 0.720 g of methylphosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.). The solids content was adjusted to 20%.

[Preparation Example E]
Flame retardant E was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 0.826 g of ethylphosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.). The solids content was adjusted to 20%.

[Preparation Example F]
Flame retardant F was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 1.036 g of butyl phosphonic acid (manufactured by Tokyo Chemical Industry Co., Ltd.). The solids content was adjusted to 20%.

[Preparation Example G]
Flame retardant G was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 0.654 g of phosphoric acid (manufactured by Rasa Kogyo Co., Ltd.). The solids content was adjusted to 20%.

[Preparation Example H]
Flame retardant H was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 0.615 g of phosphorous acid (manufactured by Tokyo Chemical Industry Co., Ltd.). The solids content was adjusted to 20%.

[Preparation Example I]
Flame retardant I was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 1.980 g of hypophosphorous acid (manufactured by Daido Pharmaceuticals). The solids content was adjusted to 20%.

[Preparation Example J]
Flame retardant J was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 1.650 g of phytic acid (manufactured by Tokyo Chemical Industry Co., Ltd.). The solids content was adjusted to 20%.

[Preparation Example K]
Flame retardant K was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 1.030 g of etidronic acid (manufactured by Chelest Co., Ltd.). The solids content was adjusted to 20%.

[Preparation Example L]
Flame retardant L was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 4.836 g of bis(2-ethilhexyl)hydrogen phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.). The solids content was adjusted to 20%.

[Preparation Example M]
Flame retardant processing agent M was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant processing agent C was replaced with 1.495 g of product name "Chilest PH-320" (manufactured by Chelest Co., Ltd., Nitrilotris (methylene phosphonic acid)). The solid content was adjusted to 20%.

[Preparation Example N]
Flame retardant N was obtained in the same manner as in Example 3, except that the dibutyl phosphate in flame retardant C was replaced with 0.103 g of "Chilest PH-430" (Phosphonobutane tricarboxylic acid). The solid content was adjusted to 20%.

[Preparation Example O]
Flame retardant agent O was obtained by adding ion-exchanged water to NONNEN R031-5 (product name: NONNEN R031-5, manufactured by Marubishi Yuka Kogyo Co., Ltd., an 80% aqueous solution of aliphatic cyclic phosphonic acid ester) to a solid content of 20%.

[Preparation Example P]
10 g of 1,3-dimethylimidazolium dimethyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in a beaker and diluted with ion-exchanged water while stirring to a solid content of 20%. Thus, a flame retardant processing agent P was obtained.

[Preparation Example Q]
10 g of Hishicolin PX-4BT (manufactured by Nippon Chemical Industry Co., Ltd., tetrabutylphosphonium benzotriazolate) was placed in a beaker and, while stirring, diluted with ion-exchanged water to an active ingredient concentration of 20%, to obtain flame retardant Q.

[Preparation Example R]
13.822 g of a 40% aqueous solution of tetrabutylphosphonium hydroxide (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in a beaker, and 5.004 g of diphenyl phosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) was gradually added while stirring, and the mixture was further stirred at room temperature for 10 minutes. The resulting aqueous solution was diluted with ion-exchanged water to a solid content of 20%, to obtain a flame retardant processing agent R.

[Examples 1 to 14 and Comparative Examples 1 to 5]
As shown in Table 1, the flame retardant obtained in each preparation example was diluted with water to a desired concentration based on the phosphorus compound to prepare a processing liquid.
Each processing solution was used to pad polyester fabric (white polyester fabric with a basis weight of 220 g/ ^m2 ) at a wringing rate of 100%. The fabric was pre-dried at 80°C for 10 minutes, and then cured at 180°C for 1 minute. The flame retardant agent on the surface of the fabric was then washed off with hot water at 50°C for 10 minutes, and dried at 80°C to obtain a flame retardant test fabric. The amount of the flame retardant agent applied to 100 parts by weight of the polyester fabric (total amount of cationic and anionic components) for each flame retardant test fabric is shown in "Drug concentration" in Table 1.

[Test Example 1]
The flame retardancy of the flame retardant test fabrics obtained in each of the Examples and Comparative Examples was evaluated. The results are shown in Table 1.
In Table 1, "-" indicates that the test was not carried out. These items failed the test even before washing with water, so further testing was discontinued.

(1) Treatment of Flame Retardant Test Cloth For the flame retardant evaluation, the flame retardant test cloth was used as it was as a sample without washing in water (denoted as "no washing"). In addition, as a sample after washing in water, the flame retardant test cloth was washed according to the method described in the Japanese Industrial Standard "JIS L 1091 (1999)" (denoted as "washing"). Furthermore, as a sample after dry cleaning, the flame retardant test cloth was dry cleaned according to the method described in the Japanese Industrial Standard "JIS L 1091 (1999)" (denoted as "dry"). Using these samples, the flame retardancy of the polyester fabric was evaluated by the following method.

(2) Evaluation of flame retardancy (2-1) Microburner test (afterflame test)
Flame retardancy was evaluated by measuring the afterflame time (seconds) and burning area ( ^cm2 ) according to the A-1 method (microburner method) described in the Japanese Industrial Standard "JIS L 1091 (1999)". The smaller the afterflame time (seconds) and burning area ( ^cm2 ), the higher the flame retardancy. The evaluation results were performed in both the vertical and horizontal directions of the flame-retardant test fabric, so two results are shown, one for the vertical direction and one for the horizontal direction.
(2-2) Coil method (flame contact test)
The flame retardancy was evaluated by measuring the number of flame contacts (the number of times the flame of a burner is required to contact the flame of the flame-retardant test fabric until it is completely melted) according to the D method (flame contact test) described in the Japanese Industrial Standard "JIS L 1091 (1999)". The higher the number of flame contacts, the higher the flame retardancy. The evaluation results are shown for both the vertical and horizontal directions of the flame-retardant test fabric, since the tests were performed in both the vertical and horizontal directions of the fabric.

As is clear from the results in Table 1, Comparative Example 1, which used 2.0% of a flame retardant made of an aliphatic cyclic phosphonic acid ester, exhibited sufficient flame retardant performance, but Comparative Example 2, which used half the concentration of the agent at 1.0%, showed insufficient flame retardant performance.

In addition, Comparative Example 3, which was composed of an imidazolium and a phosphorus-containing anion, and Comparative Example 4, which used a flame retardant composed of a phosphonium cation and a benzotriazolate, were unable to impart sufficient flame retardancy to the polyester fiber.

Furthermore, even in the case of Comparative Example 5, which uses a combination of a phosphonium cation and a phosphorus-containing anion, in which the carbon chain attached to the phosphorus-containing anion is a phenyl group rather than an alkyl group, the desired flame retardancy cannot be imparted to the polyester fiber.

In contrast to these Comparative Examples, Examples 1 to 14, which were treated with a flame retardant agent of the present invention that combines a phosphonium cation and a phosphorus-containing anion, were able to impart high flame retardancy to polyester fibers even at extremely low concentrations of 0.25 to 0.5%. Moreover, it was confirmed that the flame retardancy was adequately maintained even after washing and dry cleaning.

Claims (7)

A flame retardant processing agent comprising a phosphorus-containing cation and a phosphorus-containing anion in an aqueous solvent,
(a) the phosphorus-containing cation is a phosphonium cation represented by the formula A[P(R ¹ R ² R ³ R ⁴ )] (wherein R ¹ to R ⁴ are the same or different and represent an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 1 to 6 carbon atoms), and (b) the phosphorus-containing anion is an anion containing a group represented by the formula B[(R ⁵ )(R ⁶ )P(═O)—] (wherein R ⁵ to R ⁶ are the same or different and represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms);
A flame retardant processing agent for polyester fibers, characterized in that The cation is represented by the following formula (1):
(wherein R ¹ to R ⁴ may be the same or different and each represents an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 1 to 6 carbon atoms). The anion is
(A) Formula (2) below
(wherein R ⁵ to R ⁷ are the same or different and represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms), and (B) anions containing a group represented by formula B[(R ⁵ )(R ⁶ )P(═O)-] (wherein R ⁵ to R ⁶ are the same or different and represent a hydrogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms) (excluding the anion (A) above).
The flame retardant for polyester fibers according to claim 1, which is at least one of the following: The polyester-based flame retardant processing agent according to claim 1, in which the total amount of phosphorus-containing cations and phosphorus-containing anions in the polyester-based fiber flame retardant processing agent is 0.05 to 5.0% by weight. The polyester-based flame retardant processing agent according to claim 1, which is used to apply flame retardant treatment to polyester-based fibers by exhaustion processing or thermosol processing. A flame-retardant polyester fiber, characterized in that the polyester fiber contains the polyester fiber flame retardant processing agent described in claim 1. 7. The flame-retardant polyester fiber according to claim 6, wherein the polyester fiber flame-retardant agent is contained in an amount of 0.01 to 0.5 parts by weight as a total solid content of cationic and anionic components per 100 parts by weight of the polyester fiber.