JPH03119139A - Flameproofing and heat-resistant fabric - Google Patents

Abstract

PURPOSE:To obtain the subject fabric improved in dyeability, moisture absorptivity, etc., with hardly any heat shrinkage properties by knitting or weaving synthetic fiber, composed of flame retardant cellulosic fiber with a specific limit oxygen index and a wholly aromatic polymer containing amide groups and imide groups and having a specified melting point, etc. CONSTITUTION:The objective fabric, obtained by blending flame retardant cellulosic fiber having >=25 limit oxygen index with a wholly aromatic polymer (preferably a polyamide having >=95mol% recurring units composed of 4- methyl-1,3-phenylene terephthalamide, etc.) containing amide groups and/or imide groups at (90-60):(10-40) ratio (wt.%) and knitting or weaving the resultant synthetic fiber having >=350 deg.C melting point, >=30 deg.C (molting point - exothermic starting temperature), >=10% crystallinity, >=10% elongation, <=15% dry heat shrinkage factor at the melting point, <=3 ratio (dry heat shrinkage factor at the melting point +55 deg.C/dry heat shrinkage factor at the melting point) and suitable as clothes without perforating and causing afterglow and afterflame even in exposure to flames.

Description

[Detailed description of the invention] [Industrial application field] The present invention has low heat shrinkage and solves the problem of remaining layers.

Furthermore, it relates to a flame-resistant and heat-resistant fabric that has characteristics as a clothing fabric.

[Conventional technology]

Fully aromatic polyamide fRa is a highly flame-retardant fiber that is heat resistant, does not emit much flame even when it burns, and exhibits "self-extinguishing properties" that extinguish immediately when the flame is moved away. It is widely used in the clothing field, such as heat-resistant protective clothing, and in the interior design field. Also, poly(m-phenylene inphthalamide) #! fiber at least about 15%
and polybara phenylene terephthalamide fiber about 3 to 2
A flame-resistant fabric with a limiting oxygen index of 26.5 and containing 0% was proposed in Japanese Patent Publication No. 62-24536.
Phenylene inphthalamide)! I+! JP-A-63-196741 proposes a heat protection fabric knitted from a composite yarn in which cellulosic fibers are arranged in the core of the yarn and flame-retardant cellulose fibers are arranged in the periphery of the yarn. ing.

[Problem to be solved by the invention]

Conventional fabrics made of wholly aromatic polyamide fibers do not melt during combustion and do not cause melt drips, but when exposed to high temperatures, they shrink significantly and the fibers become firmly fused. It has the disadvantage that a hole is formed at the point where the flame comes into contact. Well, even with fully aromatic polyamide fibers, as disclosed in Japanese Patent Publication No. 62-24536, fabrics made of two types of fully aromatic polyamide fibers, meta and para, which have different chemical properties, have different melting behavior when exposed to heat. Although it is a clothing fabric that does not cause holes when exposed to a heat stream for a short time, the degree of heat shrinkage has not been significantly improved.
As fabrics for clothing, rose-based wholly aromatic polyamide fibers have a high Young's modulus, resulting in poor texture and poor passage through the spinning process. Composite yarns coated with cellulose fibers have good performance as clothing fabrics, but cellulose fibers carbonize immediately when exposed to flames, and the fully aromatic polyamide core has large fibers that shrink due to heat. The fabric shrinks, and this method is still insufficient as a countermeasure against fabric shrinkage.

Furthermore, conventional aromatic polyamide fabrics with excellent heat shrinkability have had problems with residual layers.

The present invention provides a flame-resistant and heat-resistant fabric that has excellent clothing properties (especially sensibilities such as texture and dyeability) and process passability, has low heat shrinkage, and eliminates afterflame and carelessness problems.

[Means to solve the problem]

That is, 1 the present invention provides the following (1):
～A flame-retardant material made of synthetic fibers that satisfies formula (6).
It is a heat resistant fabric.

Tm2350℃・・・・・・IT
m -Tex≧30℃ -== 2X
c≧10chi, ・・・・・・(3D
E≧10%・・・4DSR
(Tm)515% -= 5 (Tm is melting point (℃), Xc is crystallinity ('C)
, DE is elongation (%), DSR (Tm), DSR ('I
'm) is the dry heat shrinkage rate (%) at the melting point Tm, DSR (
Tm + 55°C) represents the dry heat shrinkage rate (%) at the melting point + 55°C. ) Flame-retardant cellulosic fibers with a limiting oxygen index (LOI) of 25 or more used in the present invention can be obtained by treating cellulose-based fibers such as recycled cell-based fibers or cotton with a raw yarn to make them flame-retardant.
Flame retardancy can be imparted by making a fabric into a fabric and then subjecting it to flame retardant treatment, or by spinning it as a spinning solution containing a flame retardant when producing regenerated cellulose fibers. Flame retardants for cellulosic fibers are commonly used treatment agents or additives, such as ammonium salts such as ammonium phosphate, sodium tungstate.

Titanium compounds, chlorinated or brominated paraffins, chlorinated or brominated polyolefins, polyphosphate esters 1. Phosphorus-containing reactive flame retardants are used alone or in combination, or in combination with other additives such as antimony oxide.

The flame retardancy of cellulose fibers obtained by treatment with a flame retardant is determined by the limiting oxygen index (LOI) measured using No. ) must be 25 or more. Flame retardance with a limiting oxygen index of less than 25 does not sufficiently prevent shrinkage of the fabric at high temperatures when it is knitted and woven together with the wholly aromatic polyamide fiber specified in the invention. The synthetic fibers that are made of a wholly aromatic polymer having an amide group and/or an imide group and that satisfy the above formulas (1) to (6) used in the invention have the repeating units of [D] to [■] as exemplified below. It is obtained by spinning a wholly aromatic polymer having

■ Fully aromatic polyamide (-NH-Art-NHOC-Ar2-Co-)
CI) is a divalent phenylene or biphenylene residue.

R1 represents an alkyl group having 1 to 4 carbon atoms, and R2 is hydrogen, an alkyl group having 1 to 4 carbon atoms, or an amine group.

The nitrogen position of the amide group, which represents a sulfonic acid group, carboxyl group, or hydroxyl group and is directly connected to a phenylene residue, is at the 2, 4, 2, 5, or 2.6 positions with respect to R1. R1 and R2 for biphenylene residues are 3.3 and 5.5
′. Ar2 is expressed as (2
is a valent residue, and the carbon position of the amide group bonded to the group is at the 1.4-position or the 1,3-position, and the 1,4-position:
The 1.3rd position has a repeating unit in the range of 100:0 to 80:20. ) ■ The fully aromatic polyimide rib represents a tetravalent phenylene residue represented by ■, 輔 or γ ■, and X2 represents a divalent group represented by 10- or 100- O) ■ Total Aromatic polyamideimide (wherein Ars is 1@-, -@-@- or 1@-X3
It is a divalent) unilene residue represented by -@-, and
3 is -CH2-1-〇-, -3--8o --802-
Alternatively, it represents a divalent group represented by -CO-.

3 represents a divalent phenylene residue represented by 2, R2 is hydrogen or a lower alkyl group having 1' to 4 carbon atoms, and Xl is 10-1-CO- or -01
2- represents 'n.

is a divalent phenylene residue represented by R3 is hydrogen or lower alkyl having 1 to 4 carbon atoms, and X4 is 1CH
Represents a divalent group represented by 2-, -〇- or -CO-. ) Among these wholly aromatic polymers having the repeating units [I] to [■], the wholly aromatic polyamide represented by [I] is preferable, and in particular, 95 mol% of the repeating units 9 4-methyl-1.3 -phenylene terephthalamide and/or 6-methyl-1,3-phenylene terephthalamide are preferred.

In addition, the above-mentioned wholly aromatic polymer includes, for example, (a) aromatic polyvalent incyanate and aromatic polyvalent carboxylic acid, (b)
Aromatic polyvalent incyanate and aromatic polyvalent carboxylic acid anhydride, (C) aromatic polyvalent amine and aromatic polyvalent carboxylic acid,
Obtained by polycondensing a monomer combination of (d) an aromatic polyvalent amine and an aromatic polyvalent carboxylic acid, or (e) an aromatic polyvalent amine and an aromatic polyvalent carboxylic acid ester. These polymers are, for example, N,N'-dimethylacetamide,
A spinning stock solution is prepared using a solvent such as N-methylpyrrolidone, γ-butyrolactone, dimethyl sulfoxide, tetramethylurea, N,N'-dimethylethyleneurea, etc., and the stock solution temperature is adjusted to 20-150°C, preferably 40-100°C. metal salts such as Caα2, Znα2, LiC
Temperature 30 containing 10 to 5 Qwt% of l2, LiBr, etc.
Wet spinning is carried out in an aqueous solution with a boiling point of 50°C to 100°C, preferably 50°C to 100°C, followed by 1.1 to 5 times wet heat stretching in an aqueous solution bath having approximately the same composition as the coagulation bath, and then 50°C. ~10
After thorough washing in 0°C hot water,
It is produced by drying with hot air at 300°C to 450°C, followed by dry heat stretching heat treatment of 1.1 to 5 times in air or an inert gas bath at 300°C to 450°C. During this wet spinning, it is possible to form irregularities on the surface of the resulting fiber depending on the properties of the coagulation bath, and if the fiber has such an uneven surface,
It can have a better influence on the spinnability.

The synthetic fiber made of such a wholly aromatic polymer must satisfy the following formulas (1) to (6).

350℃ above Tm Tm, -Tex≧30℃ Xc≧10%.

DE≧10% DSR (Tm)≦15% ・・・・・・(1) ・・・・・・(2) ・・・・・・(3) ・・・・・・14) 1=-(5) ( However, Tm is the melting point (C°C), and Xc is the crystallinity (C).
°C), DE is elongation (%), DSR (Tm), DSR (T
rn) is the dry heat shrinkage rate (%) at the melting point Tm, DSR (
'r'm+55°C) represents the dry heat shrinkage rate (%) at the melting point +55°C. ) To explain K in these formulas (1) to (6), Tm
(The melting point is 350°C or higher, and the Tex
(Exotherm onset temperature) is 30℃ or more low (Xc (crystallinity)
When is 10- or more, the fiber has excellent shape stability even at high temperatures above the melting point and becomes a friendly fiber.

In other words, even when Tm2350℃ and Xc≧10chi, Tm-Tex is 30℃ or more and T
Comparing fibers with m-Tex less than 30°C, the former, that is, Tex (thermal decomposition start temperature) is 30°C lower than Tm (melting point).
The lower the value, the better the morphological stability at high temperatures above the Tm (melting point) of the fiber than the latter, that is, the one where the Tex is less than 30°C than the Tm. This may seem absurd, but quite surprisingly, in fact Tex
The lower the value, the better the shape stability.

I don't really know the exact reason for this.

Tm2350℃, Xc≧10% and TeX is T
For aromatic polyamide fibers that are 30°C or more lower than m, thermal decomposition begins at a relatively low Tex, so it occurs slowly and mainly in the amorphous region, and at that time, microcrystals exist in the crystalline region without melting. .

Microcrystals act as restraint points for the molecular chains against thermal contraction that occurs as the orientation of the oriented molecular chains in the amorphous region is relaxed due to heat. It is thought that a kind of cross-linking occurs in the structure, forming a three-dimensional structure, resulting in good morphological stability even above the melting point.

On the other hand, even if Tm2350℃ and Xc≧10%', if Tex is lower than Tm by only 30℃, thermal melting will occur before a three-dimensional structure is formed due to sufficient intermolecular crosslinking. This is thought to be due to poor morphological stability due to poor fusion between heat-shrinkable fibers.

Therefore, the range of Tm - Tex is Tm - Tex230
℃, preferably Tm -Tex≧-5
'0°C, more preferably Tm-Tex270°C.

In addition, other fiber properties deteriorate to some extent at temperatures above Tm, so heat-resistant fibers that can be used at temperatures as high as 200°C or higher (compared to general synthetic fibers) have a Tm of 2350°C.
Preferably Tm≧400°C or higher, more preferably Tm≧420°C or higher.

Even if ti, Tm2350℃, Tm-Tex230℃, if the crystallinity is small (XC<10%), there is almost no restraining effect on molecular chain movement by microcrystals, so Tm
Thermal shrinkage increases rapidly from around the glass transition point, which is much lower than that, resulting in poor morphological stability.

For these reasons, it is necessary that Xc≧10%,
Preferably, Xc≧15%.

Furthermore, in order to blend fibers and flame-retardant cellulose fibers to have good bulk, processability, etc., it is important to have a balance between strength and elongation, especially sufficient elongation.D
E (!I1. fiber elongation) must be 210%. Preferably DE) 15%, more preferably DE) 20%
It is. Further, as an aspect of further increasing the shape stability at high temperatures, the fiber has a DSR (Tm)≦15%.

When the DSR ('Tm) exceeds 15%, the dry heat shrinkage is already large at the melting point, and the shape stability cannot be said to be good. If the DS, R(Tm) is 515%, heat shrinkage will increase rapidly, so if an accident occurs while wearing, for example, it will be difficult to take off the clothes, which may cause burns instead, which is preferable. It is important that the thermal shrinkage be sufficiently small even at temperatures as high as the melting point of sea urchin + 55°C.

Note that the characteristic values and physical property values of the aromatic polyamide fiber in the present invention represent values obtained using the measuring equipment and measuring conditions described below, respectively.

Tm: melting point; put approximately 10~ samples into an AI sample dish using a DSC-2C (manufactured by PerkinElmer) at f1. A DSC curve from room temperature to a predetermined temperature is obtained at 10° C. per minute in a nitrogen gas flow (3 Qml/n), and its endothermic peak temperature is defined as Tm.

Tex: Heat generation start temperature; PerkinElmer DS
A sample of approximately 10 m2 was transferred to A7 by C-2C! A DSC curve is obtained from room temperature to a predetermined temperature at 10° C. per minute in an air stream (30 d7 min), and the temperature at which heat generation starts is defined as Tex.

Crystallinity: Xc; Rigaku Denki ■-type rotating anticathode ultra-high-intensity
X2 rays) and the diffraction angle 2θ = 50 to 35, while rotating the sample in the plane perpendicular to the X-ray beam. The X-ray diffraction intensity curve in the range of
) and amorphous region (Aa), calculated from the following formula, and the ratio value Xc
Let be the crystallinity.

Xc = Ac A, +Aa x 100 (%) DE: elongation of m fiber; using an Instron tensile tester, sample length 10 cm, tensile speed 5 fractions/min, initial load 0.05 f/
It was determined by conducting a tensile test under the conditions of d.

DSR: dry heat shrinkage rate; after applying a load of Q, ls'/d to the fiber sample and measuring its length, it is treated free for 10 minutes in a hot air dryer at a predetermined temperature, and then 30 minutes later, Q
, is'/d was applied to measure the sample length Ax, and the dry heat shrinkage rate DSR was determined by the following formula.

o-Jt DSR=　　　　　　X100% Ji.

Next, the mixing ratio of the fibers made of a wholly aromatic polymer with a specific structure and the flame-retardant cellulose fibers constituting the flame-retardant/heat-resistant fabric of the present invention is in the range of 95 to 50'': 5 to 50 (wt%). If the amount of flame-retardant cellulose fibers mixed is less than 5% by weight, thermal shrinkage at high temperatures will increase, making it impossible to solve the cruelty problem.

On the other hand, if the amount of flame-retardant cellulose fibers mixed exceeds 50% by weight, the parts exposed to flame will become brittle and the strength of the fabric will decrease, which is not preferable. A more preferable mixing ratio is 90-60:10-40. In addition, fabrics made of fibers made of wholly aromatic polymers and flame-retardant cellulose fibers are produced by blending fibers made of wholly aromatic polymers and flame-retardant cellulose fibers in a spinning process to create a blended yarn. Alternatively, flame-resistant and heat-resistant fabrics can be obtained by mixing aromatic polyamide fibers and flame-retardant cellulose fibers as separate spun yarns, filament yarns, or processed yarns in the weaving and weaving process.

〔Effect of the invention〕

The flame-resistant and heat-resistant fabric of the present invention is not only melt-proof and heat-resistant, but also has low shrinkage at high temperatures, does not form holes even in areas exposed to flame, and does not cause afterflame or afterflame. Residual layers are also less likely to occur. Since it is mixed with loose cellulose fibers, the dyeability is improved, moisture absorption is imparted, and the texture is soft, making it a fabric with sufficient characteristics for use in clothing.

〔Example〕

Next, embodiments of the present invention will be explained using specific examples, but the present invention is not limited to these examples. ′
fx, unless otherwise specified, parts and percentages in the examples are as follows:
It's about weight.

In a 3E capacity separable flask equipped with a stirrer, a thermometer, a condenser, a dropping funnel, and a nitrogen introduction tube, 166.0 f (0,9991 mol) of terephthalic acid and 2.0389. lfR water N, N'-
Dimethylethylene urea l, 600ml 1. was charged under a nitrogen atmosphere and heated to 20° C. with stirring on an oil bath. Trilene-2,4- while maintaining the contents at 20θ℃
Diisocyanate 174. (1 (0,9991 mol)
t Anhydrous N, N'-dimethylethylene urea 160r
A solution dissolved in TE was added dropwise from the dropping funnel over a period of 4 hours, and after the reaction was allowed to continue for another hour, heating was stopped and the mixture was cooled to room temperature. A portion of the reaction solution was poured into strongly stirred water to precipitate a white polymer, washed with a large amount of water, and dried under reduced pressure at 150'C for about 3 hours to obtain a polymer.
Lima's logarithmic viscosity (95% H2SO40, l f/dt
, 30°C) was 2.2. Also, polymer a of the polymerization solution
The viscosity of this solution was 420 poise (B-type viscometer; 50°C). Furthermore, the obtained polymer was determined by IR spectrum and NMR spectrum.
4-methyl-1,3-phenylene terephthalamide).

The above polymerization solution is degassed under reduced pressure at 50° C. to prepare a spinning dope that does not contain air bubbles. Then, while maintaining the temperature at 50°C, the pore diameter Q and l1
54 m, from a nozzle with 600 holes (6 holes are circular) into an aqueous coagulation bath containing Ca (17240%) maintained at 80 °C.
．． Discharge at 5f/min. The filament discharged from the nozzle passes through a coagulation bath, then undergoes wet heat stretching in a bath with the same composition as the coagulation bath at a ratio of about 1.6 times, and is thoroughly rinsed with water in a washing bath consisting of 80°C warm water. An oil agent is applied and drying is carried out through a hot air bath at 150° C. to obtain a wet-heat drawn spun yarn.

The spinning yarn has an elliptical cross section but is homogeneous, with a diameter of 2.9o.
of Neil/600 filament.

Next, this spun yarn was subjected to dry heat stretching at a draw ratio of about 2.4 times using a nitrogen flow hollow dry heat drawing machine maintained at 430°C to obtain the poly(4-methyl-1,3) of the present invention.
-] diunine terephthalamide) fiber was produced (with fiber).

The physical properties of the obtained fibers are: single yarn denier = 2, strength = 5
．． 8! /dr, elongation = 25.4%, Young's modulus = 8
8y/d, Tm=425℃, Tex=330°
C, Tm-Tex=95℃, Xc=24%, DS
R (Tm) = DSR (425°C) = 11%, It can be seen that numerically it shows good general fiber physical properties and excellent shape stability at high temperatures above the melting point.

22 equipped with stirrer, thermometer and jacketed dropping funnel
250.2 f (1,232 mol) of inphthalic acid chloride and 600 M1 of anhydrous tetrahydrofuran were introduced into a jacketed separable flask and dissolved therein, and the contents were cooled to 20° C. by passing a refrigerant through the jacket. While vigorously stirring, a solution of 133.72 (1,237 mol) of metaphenylenediamine dissolved in 400 g of anhydrous tetrahydrofuran was added dropwise over about 20 minutes. The obtained white emulsion was quickly poured into water (water-cooled) containing 2.464 mol of anhydrous sodium carbonate under strong stirring. The slurry temperature immediately rose to near room temperature. Subsequently, the slurry was adjusted to a concentration of 11 with caustic soda, and the resulting cake was thoroughly washed with a large amount of water and dried overnight under reduced pressure at 150°C. The obtained polymer had a logarithmic viscosity of 1.4.

Preparation of Poly(Meta-phenylene Isophthalamide) Fiber The poly(meta-phenylene isophthalamide) or PMIA polymer powder was mixed with N-methyl-2-pyrrolion (
NMP) and NMP were dissolved in a solvent containing 2% Liα at a concentration of 22% by weight, and degassed under reduced pressure at 80°C to prepare a bubble-free spinning stock solution. Then, while maintaining the temperature at 80°C, the number of holes was 100 (6 holes were circular) with a hole diameter of 0.08IIIm.
It was discharged from a nozzle at 5.21/min into an aqueous coagulation bath containing 240% Caα maintained at 80°C, passed through a roller rotating at 10 m/min, passed through a hot water bath at 80°C, and was thoroughly rinsed with water. Moist heat drawing was carried out at 2.88 times using rollers in hot water at 98°C, and after applying an oil agent, the material was dried by passing it through a hot air bath at 150°C to obtain a spun yarn that had been drawn with heat and wet heat. The spinning yarn has a homogeneous cocoon-shaped cross section, and 3
It was 58 denier/100 filament.

Next, this spun yarn was subjected to dry heat stretching 1.88 times on a plate at 310°C to obtain poly(metaphenylene inphthalamide) fiber (fiber B).

The physical properties of the obtained fibers are: single yarn denier = 2, strength = 4
．． 9 f/d, elongation = 28.5 inches, Young's modulus = 80'
/ds Tm=42s℃, Tex=405℃, lT
m-'l'ex = 20°C, Xc = 25%, D
Although the PMI A fibers with SR (Tm) = DSR (425°C) = 16 mm and 16 mm showed good general fiber physical properties, they were poor in morphological stability at high temperatures above the melting point.

Then, the above fiber A, *fiber B and LOI of 27,5
Commercially available flame-retardant polynosic fibers having the following values were mixed in the combinations shown in Table 1, and blended yarns were prepared using a normal spun spinning method, and various 2/1 twill woven fabrics were created using the mixed yarns.

The combustion test of these woven fabrics was conducted according to JISL-1091A-4.
method (vertical method), and place the woven fabric horizontally and lower it 1) xo
Heating was carried out by heating (horizontal method) for 20 seconds using a propane gas burner flame at SO°C. The results are shown in Table 2.
ヮThe lower margin, that is, the fabric made of fully aromatic polyamide fibers and flame-retardant cellulose fibers specified in the present invention has no afterflame or residual flame, and can fuse and shrink even when exposed to high-temperature flames. The flame did not penetrate through the fabric, and it had excellent flame-blocking properties. Furthermore, the fabrics of the examples were flexible and had excellent snugness, making them suitable for clothing.

Further, when the fabric of the example was dyed in a deep reddish blue using a dye bath such as a disperse dye using a circular dyeing machine, the fabric could be dyed vividly without any graininess.

Claims (1)

[Claims] (1) Synthetic fibers that are made of flame-retardant cellulose fibers with a limiting oxygen index (LOI) of 25 or more and wholly aromatic polymers having amide groups and/or imide groups, and that satisfy the following formulas (1) to (6). A flame-resistant and heat-resistant fabric made of Tm≧350℃...(1) Tm-Tex≧30℃...(2) Xc≧10%...(3) DE≧10%...(4) DSR(Tm)≦15%...(5) DSR(Tm+55℃)/DSR(Tm)≦3……(6
) (where, Tm is melting point (℃), Tex is exothermic onset temperature (℃), Xc is crystallinity (%), DE is elongation (%), D
SR (Tm) is the dry heat shrinkage rate (%) at the melting point Tm, D
SR (Tm+55°C) represents the dry heat shrinkage rate (%) at the melting point +55°C. )