MODACRYLIC, LYOCELL, AND NYLON BLENDED FLAME-RETARDANT FABRIC

Abstract

 The present invention discloses a modacrylic-lyocell-nylon blended flame-retardant fabric. Yarns of the flame-retardant fabric contain modacrylic, lyocell and nylon, the mass ratio of each to the yarns being: modacrylic: 40-70%; lyocell: 20-52%; and nylon: 5-15%. The after-flame time of the fabric effectively blended from modacrylic, lyocell and nylon can be controlled within 2 seconds under the test condition of GB/T 5455, and the smoldering time can be controlled within 2 or 5 seconds.

Description

Field of the Invention

[0001] The present invention relates to the field of labor protection in chemicals, electric power, mining, shipbuilding, metallurgy, textiles and other industries, in particular to a flame-retardant fabric.

Background of the Invention

[0002] The blended fabric of modacrylic and non-flame retardant cotton fibers in a certain ratio has permanent flame retardancy. When the fabric is ignited on the side according to the ISO15025 standard, both the after-flame time and the smoldering time of the fabric can be controlled to less than 2 seconds to meet the specified requirements.

[0003] However, if the GB/T 5455 vertical ignition test method for fabrics is used, the after-flame time can be controlled within 2 seconds by controlling the ratios and gram weights of fibers, but it is difficult to control the smoldering time within 5 seconds or 2 seconds. The modacrylic belongs to gas phase flame retardancy to hinder the contact between oxygen and the non-flame retardant fibers and retard the burning of the non-flame retardant fibers. After the fire source is removed, the smoldering time of some non-flame retardant fibers may exceed 2 seconds, or the carbonized part may continue to glow due to the heat preservation effect, which is likely to be confused with the smoldering state and counted as the smoldering time to be unfavorable for the determination of flame retardancy of the fabric. In order to control the smoldering time within 2 seconds, the conventional method is to add 20-30% of expensive phosphorus-based flame-retardant viscose or perform post flame-retardant processing on the fabric, so the cost of the fabric is relatively high.

Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a modacrylic-lyocell-nylon blended flame-retardant fabric.

[0005] Yarns of a modacrylic-lyocell-nylon blended flame-retardant fabric contain modacrylic, lyocell and nylon, the mass ratio of each to the yarns being:

modacrylic: 40-70%;

lyocell: 20-52%;

nylon: 5-15%.

[0006] The mass ratio of each of modacrylic, lyocell and nylon to the modacrylic-lyocell-nylon blended flame-retardant fabric is:

modacrylic: 40-70%;

lyocell: 20-52%;

nylon: 5-15%.

[0007] The modacrylic-lyocell-nylon blended flame-retardant fabric according to the present invention has a gram weight of 185-338 grams per square meter.

[0008] The smoldering time of the modacrylic-lyocell-nylon blended flame-retardant fabric according to the present invention is not more than 5 seconds under the vertical burning test in accordance with GB/T 5455-2014.

[0009] Further, the smoldering time of the modacrylic-lyocell-nylon blended flame-retardant fabric according to the present invention is not more than 2 seconds under the vertical burning test in accordance with GB/T 5455-2014.

[0010] The after-flame time of the modacrylic-lyocell-nylon blended flame-retardant fabric according to the present invention is not more than 2 seconds under the vertical burning test in accordance with GB/T 5455-2014.

[0011] Two yarns are woven to the same position of the modacrylic-lyocell-nylon blended flame-retardant fabric according to the present invention every 5 mm in the warp and weft directions respectively to form gridded reinforcing ribs.

[0012] The modacrylic is a fiber generally obtained by spinning a copolymer of vinyl chloride or/and vinylidene chloride with 35-85% of acrylonitrile monomer. The fiber itself has natural flame retardancy, and in order to further improve the flame retardancy of the fiber, an antimony oxide accounting for 1-25% of the total mass of the fiber may be added. The antimony oxide may be trivalent antimony oxide, tetravalent antimony oxide or pentavalent antimony oxide, or a mixture of two or three. KANEKA's PROTEX-C type fibers are used in the examples and comparative examples.

[0013] The lyocell used in the examples and comparative examples of the present invention is Austrian Lenzing TENCEL fiber and Shanghai Rio bamboo fiber. The lyocell is a cellulosic fiber mainly spun from wood pulp or bamboo pulp by a special physical method, rather than a chemical method. The commercial lyocell mainly includes Lenzing's TENCEL made from wood pulp and Shanghai Rio's Rio bamboo fiber made from bamboo pulp.

[0014] The nylon fibers used in the present invention are commercially available nylon 6 or nylon 66 fibers.

[0015] The modacrylic-lyocell-nylon blended flame-retardant fabric provided by the present invention differs from the prior art in that:

(1) The after-flame time of the fabric effectively blended from modacrylic, lyocell and nylon can be controlled within 2 seconds under the test condition of GB/T 5455.

(2) The smoldering time of the fabric of the present invention can be controlled within 2 or 5 seconds under the test condition of GB/T 5455.

(3) Since the fabric of the present invention does not use expensive phosphorus-based flame-retardant viscose and does not require post flame-retardant, the cost of the fabric is relatively low.

[0016] The modacrylic-lyocell-nylon blended flame-retardant fabric according to the present invention will be further described below in combination with the accompanying drawings and specific embodiments.

Brief Description of the Drawings

[0017] 

FIG. 1 is a basic weave diagram of a 2/1 right twill;

FIG. 2 is a weave diagram in Examples 1-8 and 10 and Comparative Examples 1-7, 10 and 11 of the present invention;

FIG. 3 is a weave diagram in Comparative Example 9 of the present invention;

FIG. 4 is a weave diagram in Example 9 of the present invention;

FIG. 5 is a weave diagram in Example 11 of the present invention;

FIG. 6 is a weave diagram in Example 12 of the present invention;

FIG. 7 is a weave diagram in Example 13 of the present invention;

FIG. 8 is a weave diagram in Example 14 of the present invention;

FIG. 9 is a weave diagram in Comparative Example 8 of the present invention.

Detailed Description of the Embodiments

Example 1

[0018] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 70%;

tencl (1.5X38): 20%; and

nylon 6 (1.67X38): 10%.

[0019] The above fabric has a gram weight of 218 grams per square meter.

Example 2

[0020] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 70%;

Lenzing TENCEL (1.5X38): 20%; and

nylon 66 (1.67X38): 10%.

[0021] The above fabric has a gram weight of 220 grams per square meter.

Example 3

[0022] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 70%;

Rio bamboo fiber (1.67X38); 20%; and

nylon 66 (1.67X38): 10%.

[0023] The above fabric has a gram weight of 224 grams per square meter.

Example 4

[0024] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 65%;

Lenzing TENCEL (1.5X38): 20%; and

nylon 66 (1.67X38): 15%.

[0025] The above fabric has a gram weight of 221 grams per square meter.

Example 5

[0026] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 60%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 5%.

[0027] The above fabric has a gram weight of 219 grams per square meter.

Example 6

[0028] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 10%.

[0029] The above fabric has a gram weight of 217 grams per square meter.

Example 7

[0030] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 50%;

Lenzing TENCEL (1.5X38): 30%;

nylon 66 (1.67X38): 10%; and

polyimide (2.2X51): 10%.

[0031] The above fabric has a gram weight of 220 grams per square meter.

Example 8

[0032] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 40%;

Lenzing TENCEL (1.5X38): 52%; and

nylon 66 (1.67X38): 8%.

[0033] The above fabric has a gram weight of 223 grams per square meter.

Example 9

[0034] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and nylon 66 (1.67X38): 10%.

[0035] The above fabric has a gram weight of 185 grams per square meter.

Example 10

[0036] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 10%.

[0037] The above fabric has a gram weight of 203 grams per square meter.

Example 11

[0038] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 10%.

[0039] The above fabric has a gram weight of 237 grams per square meter.

Example 12

[0040] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 10%.

[0041] The above fabric has a gram weight of 281 grams per square meter.

Example 13

[0042] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 10%.

[0043] The above fabric has a gram weight of 315 grams per square meter.

Example 14

[0044] A modacrylic-lyocell-nylon blended flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 10%.

[0045] The above fabric has a gram weight of 338 grams per square meter.

[0046] Examples 1 to 14 are examples of the composition of the present invention, and all variable compositions within the scope of the present invention fall into the protection scope of the present invention.

Examples 1-8: 36/2 double yarns, the weave diagram is shown in FIG. 2. The warp and weft density is 102/62. There are 21 warps per 5 mm wide, and 2 yarns are filled to the 20^th warp. There are 13 long wefts per 5 mm, and 2 yarns are filled to the L^th weft.

Example 9: 40/2 double yarns, the weave diagram is shown in FIG. 4. The warp and weft density is 90/62. There are 18 warps per 5 mm wide, and 2 yarns are filled to the 17^th warp. There are 13 long wefts per 5 mm, and 2 yarns are filled to the L^th weft.

Example 10: 40/2 double yarns, the weave diagram is shown in FIG. 2. The warp and weft density is 102/62. There are 21 warps per 5 mm wide, and 2 yarns are filled to the 20^th warp. There are 13 long wefts per 5 mm, and 2 yarns are filled to the L^th weft.

Example 11: 32/2 double yarns, the weave diagram is shown in FIG. 5. The warp and weft density is 100/60. There are 20 warps per 5 mm wide, and 2 yarns are filled to the 19^th warp. There are 12 long wefts per 5 mm, and 2 yarns are filled to the K^th weft.

Example 12: 20/2 double yarns, the weave diagram is shown in FIG. 6. The warp and weft density is 68/46. There are 14 warps per 5 mm wide, and 2 yarns are filled to the 13^th warp. There are 10 long wefts per 5 mm, and 2 yarns are filled to the I^th weft.

Example 13: 10/1 single yarn, the weave diagram is shown in FIG. 7. The warp and weft density is 80/46. There are 16 warps per 5 mm wide, and 2 yarns are filled to the 15^th warp. There are 10 long wefts per 5 mm, and 2 yarns are filled to the I^th weft.

Example 14: 8/1 single yarn, the weave diagram is shown in FIG. 8. The warp and weft density is 64/46. There are 13 warps per 5 mm wide, and 2 yarns are filled to the 12^th warp. There are 10 long wefts per 5 mm, and 2 yarns are filled to the I^th weft.

Note:

[0047] Fabric weave: interweaving of warps and wefts.

[0048] The basic weave diagram is the smallest cycle.

[0049] 2/1 right twill is one of common weaves of woven fabrics.

[0050] FIG. 1 is a basic weave diagram of a 2/1 right twill. 1∼3 are three warps, A∼C are three wefts, the shadows indicate that the warps are on the wefts, and the non-shadows indicate that the wefts are on the warps. The right twill indicates that the upper warps are moved to the upper right corner on the whole.

[0051] The warp density is a density of warp yarns of the fabric, number of yarns/inch, 1 inch = 25.4 mm.

[0052] The weft density is a density of weft yarns of the fabric, number of yarns/inch, 1 inch = 25.4 mm.

[0053] 102X62 indicates that the warp density is 102 yarns/1 inch, and the weft density is 62 yarns/1 inch.

[0054] 8/1 (cotton count single yarn) indicates that a pound of cotton yarns has 18 lengths of 840 yards under conventional moisture regain. It is a unit for measuring the thickness of a yarn. If the value is larger, the yarn is thinner. /1 indicates a single yarn that has not been twisted. 10/1 (cotton count single yarn) indicates that a pound of cotton yarns has 10 lengths of 840 yards under conventional moisture regain. It is a unit for measuring the thickness of a yarn. If the value is larger, the yarn is thinner. /1 indicates a single yarn that has not been twisted.

[0055] 20/2 (cotton count double yarn) indicates that a pound of cotton yarns has 20 lengths of 840 yards under conventional moisture regain. It is a unit for measuring the thickness of a yarn. If the value is larger, the yarn is thinner. /2 indicates a twisted yarn of two single yarns.

[0056] 32/2 (cotton count double yarn) indicates that a pound of cotton yarns has 32 lengths of 840 yards under conventional moisture regain. It is a unit for measuring the thickness of a yarn. If the value is larger, the yarn is thinner. /2 indicates a twisted yarn of two single yarns.

[0057] 36/2 (cotton count double yarn) indicates that a pound of cotton yarns has 36 lengths of 840 yards under conventional moisture regain. It is a unit for measuring the thickness of a yarn. If the value is larger, the yarn is thinner. /2 indicates a twisted yarn of two single yarns.

[0058] 40/2 (cotton count double yarn) indicates that a pound of cotton yarns has 40 lengths of 840 yards under conventional moisture regain. It is a unit for measuring the thickness of a yarn. If the value is larger, the yarn is thinner. /2 indicates a twisted yarn of two single yarns.

[0059] 1.7X38 indicates that the fiber has a fineness of 1.7 dtex and a length of 38 mm. 10 dtex = 1 tex. 1 tex indicates 1000 m of fiber has a weight of 1 gram. If the value is larger, the fiber is thicker.

[0060] Design of 5mmX5mm special ribbed grids of 2 yarns: 2 yarns are manually filled to the place where 1 yarn should be filled every 5 mm in the latitude and longitude directions, so that the tearing strength of the fabric is improved by 10-20%.

[0061] The gram weight per square meter indicates the weight of the fabric per square meter. It is the sum of the masses of warps and wefts within one square meter of the fabric and is closely related to the warp density and the weft density.

[0062] In order to further highlight the beneficial effects of the present invention, comparative experiments are performed:

Comparative Example 1

[0063] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%; and

cotton: 45%.

[0064] The above fabric has a gram weight of 223 grams per square meter.

Comparative Example 2

[0065] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%; and

Lenzing TENCEL (1.5X38): 45%.

[0066] The above fabric has a gram weight of 224 grams per square meter.

Comparative Example 3

[0067] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%; and

Rio bamboo fiber (1.67x38); 45%.

[0068] The above fabric has a gram weight of 221 grams per square meter.

Comparative Example 4

[0069] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

cotton: 35%; and

nylon 66 (1.67X38): 10%.

[0070] The above fabric has a gram weight of 220 grams per square meter.

Comparative Example 5

[0071] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 25%; and

nylon 66 (1.67X38): 20%.

[0072] The above fabric has a gram weight of 225 grams per square meter.

Comparative Example 6

[0073] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 20%; and

nylon 66 (1.67X38): 25%.

[0074] The above fabric has a gram weight of 219 grams per square meter.

Comparative Example 7

[0075] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 50%;

Lenzing TENCEL (1.5X38): 40%; and

polyimide (2.2X51): 10%.

[0076] The above fabric has a gram weight of 223 grams per square meter.

Comparative Example 8

[0077] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 10%.

[0078] The above fabric has a gram weight of 354 grams per square meter.

Comparative Example 9

[0079] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 55%;

Lenzing TENCEL (1.5X38): 35%; and

nylon 66 (1.67X38): 10%.

[0080] The above fabric has a gram weight of 175 grams per square meter.

Comparative Example 10

[0081] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 75%;

Lenzing TENCEL (1.5X38): 15%; and

nylon 66 (1.67X38): 10%.

[0082] The above fabric has a gram weight of 222 grams per square meter.

Comparative Example 11

[0083] A flame-retardant fabric consists of the following fibers in percentage by mass:

modacrylic (1.7X38): 75%;

Lenzing TENCEL (1.5X38): 10%; and

nylon 66 (1.67X38): 15%.

[0084] The above fabric has a gram weight of 219 grams per square meter.

Comparative Examples 1-7, 10 and 11: 36/2 double yarns, the weave diagram is shown in FIG. 2. The warp and weft density is 102/62. There are 21 warps per 5 mm wide, and 2 yarns are filled to the 20^th warp. There are 13 long wefts per 5 mm, and 2 yarns are filled to the L^th weft.

Comparative Example 8: 8/1 single yarn, the weave diagram is shown in FIG. 9. The warp and weft density is 70/46. There are 14 warps per 5 mm wide, and 2 yarns are filled to the 13^th warp. There are 10 long wefts per 5 mm, and 2 yarns are filled to the I^th weft.

Comparative Example 9: 40/2 double yarns, the weave diagram is shown in FIG. 3. The warp and weft density is 84/62. There are 17 warps per 5 mm wide, and 2 yarns are filled to the 16^th warp. There are 13 long wefts per 5 mm, and 2 yarns are filled to the L^th weft.

[0085] Examples 1-14 of the present invention and Comparative Examples 1-11 are subjected to vertical burning tests in accordance with GB/T 5455-2014 to measure the after-flame and smoldering time.

[0086] Table 1 shows tested after-flame time and smoldering time.

Table 1 After-flame time and smoldering time

	After-flame time (s)	Smoldering time (s)
Example 1	0	3.1
Example 2	0	2.9
Example 3	0	3.3
Example 4	0	1.7
Example 5	0	1.9
Example 6	0	0.9
Example 7	0	1.3
Example 8	0.5	2.0
Example 9	0	0.8
Example 10	0	1.2
Example 11	0	3.2
Example 12	0	3.8
Example 13	0	4.4
Example 14	0	4.3
Comparative Example 1	0	10.2
Comparative Example 2	0	8.1
Comparative Example 3	0	9.4
Comparative Example 4	0	6.1
Comparative Example 5	3.1	Melted
Comparative Example 6	4.5	Molten drops
Comparative Example 7	0	8.3
Comparative Example 8	0	6.2
Comparative Example 9	Burnt through	Burnt through
Comparative Example 10	0	8.1
Comparative Example 11	0	7.5

[0087] From the above experimental results, the following conclusions can be drawn:
(1) The after-flame time in all examples can be controlled within 2 seconds;
(2) Regardless of the examples or comparative examples, the smoldering time cannot be controlled to 0 second;
(3) The smoldering of the modacrylic-lyocell blended flame-retardant fabric is obvious, and is more than 5 seconds. By adding 10% of polyimide, the smoldering time does not change obviously, and is more than 5 seconds, as shown in Table 2.

Table 2

	Gram weight per square meter	Modacrylic	Cotton	Lenzing TENCEL	Polyimide	Smoldering time
	g/m2	1.7X38		1.5X38	2.2X51	(s)
Comparative Example 1	223	55%	45%			10.2
Comparative Example 2	224	55%		45%		8.1
Comparative Example 7	223	50%		40%	10%	8.3

(4) In the case of ensuring that the fabric is not burnt through or melted or do not have molten drops, the smoldering time is significantly shortened by adding an appropriate proportion of nylon to the modacrylic and lyocell fibers and can be controlled within 5 seconds or 2 seconds, as shown in Table 3.

Table 3

	Gram weight per square meter	Modacrylic	Lenzing TENCEL	Rio bamboo fiber	Nylon 6	Nylon 66	Polyimide	Smoldering time
	g/m2	1.7X38	1.5X38	1.67x38	1.67X38	1.67X38	2.2X51	(s)
Example 1	218	70%	20%		10%			3.1
Example 2	220	70%	20%			10%		2.9
Example 3	224	70%		20%		10%		3.3
Example 4	221	65%	20%			15%		1.7
Example 5	219	60%	35%			5%		1.9
Example 6	217	55%	35%			10%		0.9
Example 7	220	50%	30%			10%	10%	1.3
Example 8	223	40%	52%			8%		2.0
Example 9	185	55%	35%			10%		0.8
Example 10	203	55%	35%			10%		1.2
Example 11	237	55%	35%			10%		3.2
Example 12	281	55%	35%			10%		3.8
Example 13	315	55%	35%			10%		4.4
Example 14	338	55%	35%			10%		4.3
Comparative Example 8	354	55%	35%			10%		6.2
Comparative Example 10	222	75%	15%			10%		8.1
Comparative Example 11	219	75%	10%			15%		7.5

(4) If the ratio of modacrylic is higher, the smoldering time tends to be longer, as shown in Table 4.

Table 4

	Gram weight per square meter	Modacrylic	Lenzing TENCEL	Rio bamboo fiber	Nylon 6	Nylon 66	Polyimide	Smoldering time
	g/m2	1.7X38	1.5X38	1.67x38	1.67X38	1.67X38	2.2X51	(s)
Example 1	218	70%	20%		10%			3.1
Example 2	220	70%	20%			10%		2.9
Example 3	224	70%		20%		10%		3.3
Example 4	221	65%	20%			15%		1.7
Example 5	219	60%	35%			5%		1.9
Example 6	217	55%	35%			10%		0.9

(5) If the gram weight of the fabric per square meter is larger, the smoldering time tends to be longer, as shown in Table 5.

Table 5

	Gram weight per square meter	Modacrylic	Lenzing TENCEL	Nylon 66	Smoldering time
	g/m2	1.7X38	1.5X38	1.67X38	(s)
Example 9	185	55%	35%	10%	0.8
Example 10	203	55%	35%	10%	1.2
Example 11	237	55%	35%	10%	3.2
Example 12	281	55%	35%	10%	3.8
Example 13	315	55%	35%	10%	4.4
Example 14	338	55%	35%	10%	4.3

(6) When the gram weight of the fabric per square meter is less than 185, the fabric that is burnt through during the burning test is determined as non-flame retardant, as shown in Table 6.

Table 6

	Gram weight per square meter	Modacrylic	Lenzing TENCEL	Nylon 66	Smoldering time
	g/m2	1.7X38	1.5X38	1.67X38	(s)
Comparative Example 9	175	55%	35%	10%	Burnt through

(7) When the gram weight of the fabric per square meter is more than 338, the smoldering time of the fabric during the burning test is more than 5 seconds, as shown in Table 7.

Table 7

	Gram weight per square meter	Modacrylic	Lenzing TENCEL	Nylon 66	Smoldering time
	g/m2	1.7X38	1.5X38	1.67X38	(s)
Comparative Example 8	354	55%	35%	10%	8.3

(8) In the presence of a small amount of polyimide fibers, the addition of nylon to the modacrylic and lyocell fibers is still advantageous for controlling smoldering, as shown in Table 8.

Table 8

	Gram weight per square meter	Modacrylic	Lenzing TENCEL	Nylon 66	Polyim ide	Smoldering time
	g/m2	1.7X38	1.5X38	1.67X38	2.2X51	(s)
Example 7	220	50%	30%	10%	10%	1.3
Comparative Example 7	223	50%	40%		10%	8.3

(9) When the content of nylon exceeds 15%, the fabric that is melted or has molten drops during the burning test is determined as non-flame retardant, as shown in Table 9.

Table 9

	Gram weight per square meter	Modacrylic	Lenzing TENCEL	Nylon 66	Smoldering time
	g/m2	1.7X38	1.5X38	1.67X38	(s)
Comparative Example 5	225	55%	25%	20%	Melted
Comparative Example 6	219	55%	20%	25%	Molten drops

(10) The smoldering time of the blended fabric of modacrylic and cotton is longer than that of the blended fabric of modacrylic and lyocell, as shown in Table 10, but still cannot be controlled within 5 seconds after 10% of nylon is added. In the present invention, only when the modacrylic, the lyocell, and the nylon are blended together and satisfy the allowable range of the present invention, the smoldering time can be controlled within 5 seconds or 2 seconds, as shown in Table 11.

Table 10

	Gram weight per square meter	Modacrylic	Cotton	Lenzing TENCEL	Rio bamboo fiber	Smoldering time
	g/m2	1.7X38		1.5X38	1.67x38	(s)
Comparative Example 1	223	55%	45%			10.2
Comparative Example 2	224	55%		45%		8.1
Comparative Example 3	221	55%			45%	9.4

Table 11

	Gram weight per square meter	Modacrylic	Cotton	Lenzing TENCEL	Nylon 66	Smoldering time
	g/m2	1.7X38		1.5X38	1.67X38	(s)
Example 6	217	55%		35%	10%	0.9
Comparative Example 4	220	55%	35%		10%	6.1

[0088] If the conventional design is used, 15% of Lenzing's phosphorus-based flame-retardant viscose is added and 15% of Lenzing TENCEL or Rio bamboo fiber is reduced to control the smoldering, the cost of raw materials will rise relatively. Table 12 shows conventional prices on the market.

Table 12

Fiber name	Specification	Unit price of fiber Yuan/kg
Modacrylic	1.7X38	65
Lenzing's phosphorus-based flame-retardant viscose	1.5X38	105
Lenzing TENCEL	1.5X38	22
Rio bamboo fiber	1.67x38	45
Nylon 6	1.67X38	25
Nylon 66	1.67X38	30
Polyimide	2.2X51	205

[0089] Calculated by 20% of loss from conventional fibers to a fabric, the cost is increased as shown in Table 13 if the flame-retardant viscose is used to control the smoldering.

Table 13

	Yuan/m	Raw material cost after the use of flame-retardant viscose (Yuan/m)	Raw material cost increase (Yuan/m)	Raw material cost increase (%)
Example 1	13.71	16.96	3.26	23.76%
Example 2	13.97	17.25	3.29	23.53%
Example 3	15.46	17.88	2.42	15.65%
Example 4	13.56	16.87	3.30	24.34%
Example 5	12.67	15.94	3.27	25.83%
Example 6	12.10	15.34	3.24	26.80%
Example 7	16.53	19.81	3.29	19.89%
Example 8	10.66	13.99	3.33	31.25%
Example 9	10.31	13.08	2.76	26.80%
Example 10	11.32	14.35	3.03	26.80%
Example 11	13.21	16.75	3.54	26.80%
Example 12	15.66	19.86	4.20	26.80%
Example 13	17.56	22.26	4.71	26.80%
Example 14	18.84	23.89	5.05	26.80%

Note: Raw material increase cost = [∑ phosphorus-based flame-retardant viscose (fiber unit price × fiber ratio) - ∑ phosphorus-free flame-retardant viscose (fiber unit price × fiber ratio)] × gram weight of the fabric per square meter/ 1000; Raw material increase cost = raw material increase cost/ raw material cost before the use of flame-retardant viscose × 100%.

[0090] It can be seen from the above table that the cost of raw materials will increase by 15.65-31.25% with the use of the conventional phosphorus-based viscose, and the cost of using the technical solution of the present invention is relatively low.

[0091] If the phosphorus-based flame-retardant viscose is not used and the smoldering time is reduced by post flame-retardant treatment, the cost of raw materials will not increase, but the processing cost correspondingly increases, and at the same time, when the post flame-retardant treatment is performed, the color of the fabric changes to a certain extent, the physical properties also decrease to a certain extent, and the problems about health, sanitation and environment friendliness such as formaldehyde are also caused. The processing fee of the conventional post flame-retardant treatment is 6 yuan/m. If the processing cost is 4 yuan/m, the processing cost increases greatly. The specific values are shown in Table 14.

Table 14

	Raw material cost before post flame-retardant treatment (Yuan/m)	Processing cost increase (Yuan/m)	Increased processing cost (%)
Example 1	13.71	4.00	29.18%
Example 2	13.97	4.00	28.64%
Example 3	15.46	4.00	25.88%
Example 4	13.56	4.00	29.49%
Example 5	12.67	4.00	31.58%
Example 6	12.10	4.00	33.07%
Example 7	16.53	4.00	24.20%
Example 8	10.66	4.00	37.52%
Example 9	10.31	4.00	38.79%
Example 10	11.32	4.00	35.35%
Example 11	13.21	4.00	30.28%
Example 12	15.66	4.00	25.54%
Example 13	17.56	4.00	22.78%
Example 14	18.84	4.00	21.23%

Note: Increased processing cost = processing cost increase/ raw material cost before post flame-retardant treatment × 100%.

[0092] The processing cost increases 21.23-31.58% relative to the raw material cost before post flame-retardant treatment. It can also be proved that the solution of the present invention is economical.

[0093] Described above are merely preferred embodiments of the present invention, and the scope of the present invention is not limited thereto. Various modifications and improvements made by those of ordinary skill in the art without departing from the design spirit of the present invention shall fall into the protection scope defined by the claims of the present invention.

Industrial practicability

[0094] The fabric of the present invention is made by effective blending of modacrylic, lyocell and nylon. The modacrylic is a fiber generally obtained by spinning a copolymer of vinyl chloride or/and vinylidene chloride with 35-85% of acrylonitrile monomer. The fiber itself has natural flame retardancy, and in order to further improve the flame retardancy of the fiber, an antimony oxide accounting for 1-25% of the total mass of the fiber may be added. The lyocell is a cellulosic fiber mainly spun from wood pulp or bamboo pulp by a special physical method rather than a chemical method. The nylon fibers used in the present invention are conventional nylon 6 or nylon 66 fibers. The after-flame time of the fabric of the present invention can be controlled within 2 seconds under the test condition of GB/T 5455, and the smoldering time can be controlled within 2 or 5 seconds under the test condition of GB/T 5455. Since the fabric of the present invention does not use expensive phosphorus-based flame-retardant viscose and does not require post flame-retardant treatment, the cost of the fabric is relatively low. Hence, the fabric provided by the present invention has a significant flame-retardant effect and good industrial applicability.

Claims

1. A modacrylic-lyocell-nylon blended flame-retardant fabric, wherein yarns in the fabric contain modacrylic, lyocell and nylon, the mass ratio of each to the yarns being:

modacrylic: 40-70%;

lyocell: 20-52%;

nylon: 5-15%.

2. The modacrylic-lyocell-nylon blended flame-retardant fabric according to claim 1, wherein the mass ratio of each of modacrylic, lyocell and nylon in the fabric to the fabric is:

modacrylic: 40-70%;

lyocell: 20-52%;

nylon: 5-15%.

3. The modacrylic-lyocell-nylon blended flame-retardant fabric according to claim 2, wherein the gram weight is 185-338 grams per square meter.

4. The modacrylic-lyocell-nylon blended flame-retardant fabric according to claim 3, wherein the smoldering time is not more than 5 seconds under the vertical burning test in accordance with GB/T 5455-2014.

5. The modacrylic-lyocell-nylon blended flame-retardant fabric according to claim 3, wherein the smoldering time is not more than 2 seconds under the vertical burning test in accordance with GB/T 5455-2014.

6. The modacrylic-lyocell-nylon blended flame-retardant fabric according to claim 3, wherein the after-flame time is not more than 2 seconds under the vertical burning test in accordance with GB/T 5455-2014.

7. The modacrylic-lyocell-nylon blended flame-retardant fabric according to claim 4, wherein two yarns are woven to the same position of the fabric every 5 mm in the warp and weft directions respectively to form gridded reinforcing ribs.

Drawing