JP2001172863A - Water-resistant, flame-retardant nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a halogen-free nonwoven fabric having high water resistance and flame retardance. SOLUTION: This nonwoven fabric is obtained by coating or impregnating a nonwoven fabric with a flame retardance imparting aqueous composition comprising 10-150 pts.wt. of a phosphazene compound based on 100 pts.wt. of an ethylene-based copolymer in an aqueous emulsion of the copolymer and drying the nonwoven fabric to solve the subject.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric having excellent water resistance and flame retardancy, and more particularly to a flame retardant air filter having improved washing resistance.

[0002]

2. Description of the Related Art Non-woven fabrics commonly used as filters and carpets are made of rayon, acetate, nylon,
Synthetic fiber webs, such as polyester, are used, for example, in SBR,
Although bonded with a binder such as NBR, they have poor self-extinguishing properties and have the property of being burned out when ignited. Therefore, various studies have been conducted to make these nonwoven fabrics flame-retardant. Generally, a method of coating or impregnating a fabric with a compound containing an element such as halogen or phosphorus together with a binder is mainly used for making the fiber flame-retardant. Among them, the method using a halogen compound tends to generate harmful gas during combustion, and its use is restricted or prohibited from the viewpoint of environmental protection. Further, most phosphorus-based compounds that have been used as flame retardants are phosphate ester-based compounds, and therefore have poor water resistance and poor affinity with synthetic fibers. Therefore, it is not practical for post-processing.

[0003]

SUMMARY OF THE INVENTION The present invention provides a halogen-free flame-retardant non-woven fabric which has excellent water resistance, mechanical strength and flame retardancy and does not generate harmful gases at the time of fire or incineration. It is in.

[0004]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted various studies on flame retardants for post-processing nonwoven fabrics. As a result, the phosphazene compound was insoluble in water and the phosphorus content was low. The inventors have found that they impart high water resistance and flame retardancy to a nonwoven fabric, and based on this finding, have further studied and completed the present invention. That is, the present invention
(1) Copolymer 1 in ethylene copolymer emulsion
A water-resistant, flame-retardant nonwoven fabric obtained by coating or impregnating a nonwoven fabric with a flame retardancy-imparting composition containing 10 to 150 parts by weight of a phosphazene compound based on 00 parts by weight, and (2) a phosphazene compound represented by the formula ( 1)

Embedded image (Wherein, n is an integer of 3 to 10) The water-resistant, flame-retardant nonwoven fabric according to the above (1), which is a linear or cyclic phosphazene compound represented by the following formula (1): The water-resistant, flame-retardant nonwoven fabric according to the above (2), which is a cyclic phosphazene compound of 3 or 4, and the (4) water-resistant, flame-retardant nonwoven fabric according to the above (1), wherein the nonwoven fabric is a filter. The water-resistant, flame-retardant nonwoven fabric according to the above (4), which is a filter.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The nonwoven fabric used in the present invention is obtained by molding fibers such as synthetic fibers, natural fibers, semi-synthetic or regenerated fibers into a mat or thin cotton, and then using a binder or heat-sealing the fibers. It is a fabric that combines fibers by doing, and has excellent shrink resistance, water resistance, and solvent resistance,
It is frequently used for interlining and lining of clothing, carpets, air filters, etc. Examples of the fiber material of the nonwoven fabric include synthetic fibers such as polyester, polyamide, nylon, polyolefin, acetate, and rayon, and natural fibers such as cotton, hemp, and wool. In the present invention, any of them can be used. The ethylene-based copolymer aqueous emulsion used in the present invention is an emulsion polymerization of an ethylene-based monomer in an aqueous medium in the presence or absence of a surfactant and / or a protective colloid, or an emulsion other than emulsion polymerization. Aqueous copolymer aqueous emulsion obtained by post-emulsifying a copolymer polymerized by the method, or a mixture of a plurality of these aqueous copolymer emulsions, such as ease of production, economy and the like For this reason, it is preferable that the copolymer emulsion is usually a single copolymer emulsion obtained by emulsion polymerization of an ethylene monomer or a mixture of a plurality of copolymer emulsions.

Examples of the ethylene monomer include acrylic acid such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isononyl acrylate, lauryl acrylate, and stearyl acrylate. Alkyl ester monomers,
For example, methyl methacrylate, ethyl methacrylate,
Alkyl methacrylate monomers such as n-butyl methacrylate, 2-ethylhexyl methacrylate and stearyl methacrylate, for example, aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene and ethylvinylbenzene, for example, acetic acid Saturated fatty acid vinyl monomers such as vinyl, vinyl propionate and vinyl versatate, for example, vinyl cyanide monomers such as acronitrile and methacrylonitrile, for example, olefin monomers such as ethylene, propylene and butadiene body,
For example, acrylic acid, methacrylic acid, crotonic acid, citraconic acid, itaconic acid, maleic acid, ethylene carboxylic acid such as fumaric acid, for example, ethylene carboxylic anhydride such as maleic anhydride, such as monobutyl maleic acid Monoalkyl esters of ethylene-based dicarboxylic acids,
And ethylene-based carboxylate salts such as ammonium salts or alkali metal salts thereof; for example, acid amides of ethylene-based carboxylic acids such as acrylamide, methacrylamide, and diacetone acrylamide; for example, N-methylolacrylamide, N-methylolmethacrylamide Methylolated diacetone acrylamide, and methylolated ethylene-based carboxylic acid amides such as etherified products of these monomers and alcohols having 1 to 8 carbon atoms (for example, N-isobutoxymethylacrylamide); Derivatives, such as glycidyl acrylate,
Esters of an ethylene-based carboxylic acid such as glycidyl methacrylate and an alcohol having an epoxy group, for example, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, hydroxyalkyl esters of an ethylene-based carboxylic acid such as 2-hydroxymethacrylate, for example, , Dimethylaminoethyl methacrylate, esters of an ethylenic carboxylic acid such as diethylaminoethyl methacrylate and an alcohol having an amino group, for example, divinylbenzene, diallyl phthalate,
Examples of the monomer include two or more non-conjugated unsaturated groups such as triallyl cyanurate and diethylene glycol dimethacrylate.

The type and amount of the ethylene monomer are not particularly limited, and can be appropriately selected depending on various required physical properties of the nonwoven fabric to be subjected to flame-retardant processing. For example, in a field requiring a relatively firm texture such as an air filter or a carpet laid on an automobile floor or deck, an ethylene monomer having a glass transition point (Tg) of 10 ° C. or more, preferably 20 to 150 ° C. is used. preferable. The ethylene-based copolymer aqueous emulsion of the present invention,
Usually, an ethylene-based monomer appropriately selected from the monomer group is added in the presence of a surfactant and / or a protective colloid.
It is a single copolymer emulsion obtained by emulsion polymerization in an aqueous medium, or a mixture of a plurality of these copolymer emulsions. Examples of the surfactant include polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl phenol ethers, sorbitan fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene fatty acid esters, glycerin fatty acid esters, poly Nonionic surfactants such as oxyethylene polyoxypropylene block copolymers, for example, fatty acid salts, alkyl aryl sulfonates, alkyl sulfur ester salts,
Alkyl sulfosuccinate salts and derivatives thereof, polyoxyalkylene alkyl ether sulfate salts, anionic surfactants such as polyoxyalkylene alkyl aryl ether sulfate salts, for example,
A cationic surfactant such as an alkylamine salt, a quaternary ammonium salt, or a polyoxyethylalkylamine; and
For example, an amphoteric surfactant such as alkyl betaine may be used. Reactive surfactants can also be used.

The surfactant is usually used in an amount of about 0.1 to 10% by weight based on the total amount of the ethylene monomer, and is suitable for the reaction of emulsion polymerization, the stability of the obtained resin aqueous emulsion and the water resistance. In view of the above, it is preferable to use about 0.5 to 7% by weight. Examples of the protective colloid that can be used in the present invention include polyvinyl alcohols and cellulose derivatives, and these can be used alone or in combination.
The amount used can be appropriately selected, and for example, about 0.5 to 10% by weight based on the total amount of the ethylene monomer used can be exemplified. The solid content of the aqueous ethylene-based copolymer emulsion used in the present invention is not particularly limited, but is preferably about 30 to 65% by weight from the viewpoint of productivity and ease of production. Examples of the phosphazene compound used in the present invention include compounds represented by the formula (2)

Embedded image (Wherein X ¹ and X ² are the same or different and are an optionally substituted alkoxy group or an optionally substituted aryloxy group, and n is 3 to 10. And a) a linear or cyclic compound having a repeating structural unit. Examples of the alkoxy group represented by X ¹ and X ² include an alkoxy group having 1 to 3 carbon atoms such as methoxy, ethoxy, and propoxy. Examples of the aryloxy group include phenoxy and naphthoxy. Examples include an alkyl group such as ethyl.
Among them, a phosphazene compound represented by the formula (1) in which X ¹ and X ² are both phenoxy groups is more preferably used.

In particular, in formula (1), a cyclic phosphazene compound in which X ¹ and X ² are both a phenoxy group and n is 3 or 4 is preferably used, and a typical example of the compound is a commercially available trade name : CP-134H, S
PS-100 (all manufactured by Otsuka Chemical Co., Ltd.) and the like. As a mode of incorporating the phosphazene compound into the aqueous ethylene-based copolymer emulsion, a method of mixing powder of the phosphazene compound into the aqueous ethylene-based copolymer emulsion, and adding the phosphazene compound into the ethylene-based monomer mixture to copolymerize There are methods. In this case, the amount of the phosphazene compound used is 10 to 1 based on 100 parts by weight of the copolymer in the ethylene-based copolymer aqueous emulsion.
It is 50 parts by weight, preferably 30 to 70 parts by weight. The ethylene-based copolymer aqueous emulsion containing the phosphazene compound, that is, the flame-retardant-imparting aqueous composition, may also contain a crosslinking agent in order to improve the physical properties of the copolymer. Examples of the crosslinking agent include an aqueous solution or aqueous dispersion of zinc oxide, an aqueous solution or aqueous dispersion of blocked isocyanate, and an aqueous solution or aqueous dispersion of a melamine-formaldehyde resin. The compounding amount of these crosslinking agents is usually 1 to 20 parts by weight, preferably 2 to 15 parts by weight, based on 100 parts by weight of the solid content of the aqueous ethylene copolymer emulsion.

The flame-retardant aqueous composition of the present invention further comprises:
Other flame retardants can be used in combination within a use range that does not impair the excellent effects of the present invention. Examples of the flame retardant include flame retardants that do not generate toxic gas at the time of fire, such as antimony compounds, boron compounds, aluminum compounds, magnesium compounds, and zirconium compounds. Among these, aluminum compounds,
Particularly, aluminum hydroxide is preferable. The amount of these flame retardants used is, for example, 30 to 25 parts by weight per 100 parts by weight of the copolymer (solid content) in the ethylene copolymer emulsion.
About 0 parts by weight can be exemplified. As a measure of the flame retardancy in the present invention, those having a flammability class of 2 or 3 according to JIS L1091, AI method. Also,
In the use range not hindering the excellent effects of the present invention, further inorganic fillers, dispersants, thickeners, wetting agents, foaming agents, foaming agents, defoamers, pigments, dyes, plasticizers, antioxidants, UV absorbers, preservatives and the like can be used. The solid content, pH and viscosity of the flame-retardant-imparting aqueous composition of the present invention obtained as described above are not particularly limited, but from the viewpoint of sedimentation stability of the composition, Generally 30-30 solids
0% by weight, preferably about 35 to 60% by weight, and the pH is 4
-10, preferably 6-10, viscosity (20 ° C, 12 rp
m) is from 500 to 1,500 mPa · s, preferably from 500 to
It is 2,000 mPa · s. To apply the flame retardant-imparting aqueous composition to the nonwoven fabric, a calendar method, an immersion method, a spray method,
Any method known per se, such as a roll method, a knife method, and a brush application method, may be used, but an immersion method can be conveniently used. The drying of the nonwoven fabric coated or impregnated with the flame-retardant-imparting aqueous composition is performed at a temperature of 100 ° C or higher, preferably 110 to 180 ° C.

[0011]

The present invention will be described in more detail with reference to the following examples, comparative examples and test examples, but the present invention is not limited thereto. Example 1 400 g of ion-exchanged water and 0.2 g of sodium dodecylbenzenesulfonate were placed in a reaction vessel equipped with a stirrer, a dropping funnel, a nitrogen gas inlet tube, a thermometer, and a reflux condenser.
And dissolved by heating. After the inside of the container was replaced with nitrogen, the temperature was raised to 60 ° C., and while maintaining the temperature, ethyl acrylate 1 was added.
97 g, a mixture of 223 g of methyl methacrylate and 13 g of methacrylic acid, an aqueous solution obtained by dissolving 1.5 g of sodium dodecylbenzenesulfonate, 18 g of polyoxyethylene nonylphenyl ether and 13 g of N-methylolacrylamide in 120 g of deionized water, 25 g of a 4% aqueous ammonium persulfate solution 25 g of 2% aqueous sodium bisulfite solution
The mixture was added continuously over a period of time, emulsion polymerization was performed, and then neutralized with aqueous ammonia. The obtained ethylene copolymer emulsion had a solid content of about 45%, a pH of 7.5, and a viscosity of 80 mPa · s (2
(5 ° C., 30 rpm), and the copolymer had a Tg of 33 ° C. In 206 g of water, 30 g of a phenoxyphosphazene oligomer (CP-134H, manufactured by Otsuka Chemical Co., Ltd.), which is an equal mixture of a cyclic compound having n = 3 and a cyclic compound having n = 4 in the above formula (1), sodium succinate After adding 0.3 g and subjecting to a bead mill, 200 g of aluminum hydroxide powder was further added and stirred well to prepare an aqueous dispersion. To this aqueous dispersion, 222 g of the copolymer emulsion (100 g of solid content),
4 g (1 g of solid content) of Ultrasol V-280 (manufactured by Ganz Kasei Co., Ltd.) as a thickener was added and stirred, and the solid content was 50% and the viscosity was 1,000 mPa · s (20 ° C., 12 rpm)
m) was obtained. A web (100 g / m ² ) made of polyester fiber was treated with a binder (150 g / m ² ) containing equal amounts of SBR and a melamine resin to prepare a nonwoven fabric for an air filter. The flame retardant-imparting aqueous composition is dipped in the obtained nonwoven fabric by a dipping method for 200 hours.
g / m ^{2 and} dried at 150 ° C. for 10 minutes to prepare a flame-retardant air filter.

Examples 2 to 4 A flame-retardant air filter was prepared in the same manner as in Example 1 except that the phenoxyphosphazene oligomers in Example 1 were used in the amounts shown in Table 1.

Comparative Example 1 An aqueous emulsion was prepared in the same manner as in Example 1 except that the phenoxyphosphazene oligomer was not used.

Comparative Example 2 100 parts by weight of the copolymer emulsion of Example 1 was mixed with a phosphate ester-based flame retardant (Nikka Finon P-100,
40 parts by weight of Nikka Chemical Co., Ltd.) were blended to obtain a flame-retardant aqueous composition. This composition was impregnated into a nonwoven fabric in the same manner as in Example 1, and dried to prepare an air filter.

Test Example 1 Each of the air filters obtained in Examples 1 to 4 and Comparative Examples 1 and 2 was cut into a sample of 350 mm × 250 mm to obtain a sample. This sample was tested according to the A-1 method of JIS L1091 “Test method for flammability of textiles”, and the results are summarized in [Table 1].

[Table 1]

The combustion classifications shown in Table 1 are based on JIS.
The combustion test method of L1091 A-1 method was followed. The flammability classification is as shown in [Table 2].

[Table 2] As is clear from the results of the above flammability test, Example 1
The flame-retardant nonwoven fabrics of Nos. To 4 had a flammability category of 2 or more. In particular, any of the nonwoven fabrics impregnated with the flame retardancy-imparting aqueous composition containing the phenoxyphosphazene oligomer in an amount of 40 parts by weight or more exhibited flame retardancy of combustion category 3. The flame retardancy remained almost unchanged after washing. On the other hand, the nonwoven fabric of Comparative Example 1 containing no flame retardant completely burned, and Comparative Example 2 impregnated with a composition containing a phosphate ester-based flame retardant.
Although the nonwoven fabric showed relatively good flame retardancy before washing, the flame retardancy after washing was reduced to combustion category 1 at a stroke. This shows that the product of the present invention has high water resistance and flame retardancy.

[0017]

The water-resistant and flame-retardant nonwoven fabric of the present invention has high water resistance and flame retardancy despite being halogen-free, and its flame retardancy hardly decreases even by washing.

Claims (5)

[Claims] 1. A non-woven fabric is coated or impregnated with a flame-retardant composition containing 10 to 150 parts by weight of a phosphazene compound per 100 parts by weight of a copolymer in an ethylene copolymer emulsion, and dried. A water-resistant, flame-retardant non-woven fabric. 2. The phosphazene compound of the formula (1) The water-resistant and flame-retardant nonwoven fabric according to claim 1, wherein the compound is a linear or cyclic phosphazene compound represented by the formula (where n is an integer of 3 to 10). 3. The water-resistant, flame-retardant nonwoven fabric according to claim 2, wherein the phosphazene compound is a cyclic phosphazene compound wherein n in the formula (1) is 3 or 4. 4. The water-resistant, flame-retardant nonwoven fabric according to claim 1, wherein the nonwoven fabric is a filter. 5. The water-resistant, flame-retardant nonwoven fabric according to claim 4, wherein the filter is an air filter.