FLAME RETARDANT YARN

Abstract

The flame retardant yarn of the present invention is made by blending flame retardant viscose fiber and at least one high tenacity flame retarding fiber, the at least one high tenacity flame retarding fiber is flame retardant polyester or flame retardant finishing viscose fiber, wherein the flame retardant viscose fiber is 40˜90% by weight of the flame retardant yarn. The flame retardant yarn takes advantage of the superior flame retardance of the flame retardant viscose fiber, and takes the flame retardant viscose fiber to blend with other good tenacity and spinnability fiber by adjusting amount of raw materials in reasonable balance and avoiding disadvantages of the raw materials to optimize advantages of the flame retardant viscose fiber such as flame retardancy and tenacity so as to provide the flame retardant viscose fiber with high flame retardancy, long lasting flame retardancy effect, strength and elongation performance and good abrasion resistance. Fabric made by the flame retardant yarn not only has good flame retardancy, but also has good elasticity due to high tenacity of the flame retardant yarn.

Claims

1. A flame retardant yarn, wherein the flame retardant yarn is made by blending flame retardant viscose fiber and at least one high tenacity flame retarding fiber, the at least one high tenacity flame retarding fiber is flame retardant polyester or flame retardant finishing viscose fiber; wherein the flame retardant viscose fiber is 40˜90% by weight of the flame retardant yarn.

2. The flame retardant yarn as claimed in claim 1, wherein the flame retardant yarn is made by blending the flame retardant viscose fiber and the flame retardant polyester, the weight percentages of the flame retardant viscose fiber and the flame retardant polyester are 65˜90% and 10˜35% respectively.

3. The flame retardant yarn as claimed in claim 1, wherein the flame retardant yarn is made by blending the flame retardant viscose fiber, the flame retardant polyester and flame retardant finishing viscose fiber, the weight percentages of the flame retardant viscose fiber, the flame retardant polyester and flame retardant finishing viscose fiber are 40˜60%, 10˜20% and 30˜50% respectively.

4. The flame retardant yarn as claimed in claim 1, wherein the flame retardant yarn is made by blending the flame retardant viscose fiber and flame retardant finishing viscose fiber, the weight percentages of the flame retardant viscose fiber and flame retardant finishing viscose fiber are 60˜80% and 20˜40% respectively.

5. The flame retardant yarn as claimed in claim 1, wherein the flame retardant yarn comprises the flame retardant polyester no more than 30% by weight and having breaking strength no less than 5.1 cN/dtex.

6. The flame retardant yarn as claimed in claim 2, wherein the flame retardant yarn comprises the flame retardant polyester no more than 30% by weight and having breaking strength no less than 5.1 cN/dtex.

7. The flame retardant yarn as claimed in claim 3, wherein the flame retardant yarn comprises the flame retardant polyester no more than 30% by weight and having breaking strength no less than 5.1 cN/dtex.

8. The flame retardant yarn as claimed in claim 1, wherein the flame retardant yarn comprises the flame retardant viscose fiber no less than 50% by weight and having limiting oxygen index no less than 32.

9. The flame retardant yarn as claimed in claim 2, wherein the flame retardant yarn comprises the flame retardant viscose fiber no less than 50% by weight and having limiting oxygen index no less than 32.

10. The flame retardant yarn as claimed in claim 3, wherein the flame retardant yarn comprises the flame retardant viscose fiber no less than 50% by weight and having limiting oxygen index no less than 32.

11. The flame retardant yarn as claimed in claim 4, wherein the flame retardant yarn comprises the flame retardant viscose fiber no less than 50% by weight and having limiting oxygen index no less than 32.

12. A method for preparing flame retardant finishing viscose fiber, wherein the method includes: step 1: turning viscose fibers to cellulose filaments in a manufacture of viscose fibers, making cellulose tows by entering the cellulose filaments on a spinning machine into an acid coagulation bath, and washing the cellulose tows 2˜3 times by clean water; step 2: soaking the cellulose tows of step 1 in a solution dissolved with flame retardant by a bath ratio of 1˜2:10, and stirring every 30 minutes, wherein the flame retardant is 10˜15% by weight of the cellulose tows, the soaking temperature is 50˜60° C., the soaking time is 1˜5 hours; step 3: taking the cellulose tows out of the solution and drying the cellulose tows at a temperature below 180° C. to obtain the flame retardant finishing viscose fibers.

13. The method as claimed in claim 12, wherein the flame retardant is of phosphorus-nitrogen type including phosphoric acid tris(2-chloroethyl) ether, phosphoric acid tris(2,3-dichloropropyl) ether), triphosphate(2,3-dibromopropyl) ether, dimethyl methylphosphonate ether, phosphoric acid tris (ethyl butyl) ether, or combination thereof.

14. A high tenacity flame retarding fabric, made by the flame retardant yarn as claimed in claim 1.

15. The high tenacity flame retarding fabric as claimed in claim 14, wherein the flame retardant finishing viscose fiber is prepared by a method includes: step 1: turning viscose fibers to cellulose filaments in a manufacture of viscose fibers, making cellulose tows by entering the cellulose filaments on spinning machine into an acid coagulation bath, and washing the cellulose tows 2˜3 times by clean water; step 2: soaking the cellulose tows of step 1 in a solution including a flame retardant with a bath ratio of 1˜2:10, and stirring every 30 minutes, the flame retardant is 10˜15% by weight of the cellulose tows, the soaking temperature is 50˜60° C., the soaking time is 1˜5 hours; step 3: taking the cellulose tows out of the solution and drying the cellulose tows at a temperature below 180° C. to obtain flame retardant finishing viscose fibers.

Description

DESCRIPTION OF THE INVENTION

[0030] The embodiments of the present invention are described below for the invention easier to be understood. However, the invention should not be construed as being limited to the methods, conditions or references in the embodiments set forth herein. In contrast, the terms are provided in embodiments so that the scope of the invention will be fully understood by those skilled in the art and should not limit the scope of the invention.

[0031] Viscose fibers use natural cellulose fibers as raw materials. The raw materials are processed by alkali treatment to break hydrogen bonds inside individual molecule or between molecules, and reacted with CS.sub.2 to form cellulose xanthate which is then by mixing, filtering, deaeration and curing etc. to obtain spinning viscose with good spinnability. A spinning process includes preparing viscose fibers that are made up of viscose in an acid bath condition by use of spinning machine, then proceeding washing, desulfurizing, bleaching, pickling, drying, etc. to obtain good quality viscose fibers. Flame retardant viscose fibers are made by making flame retardants blended in or bonded to cellulose before the normal viscose fiber spinning procedure and then proceeding the spinning process, or making the flame retardants clung to viscose fibers through physical or chemical means after the spinning process. At present, blending flame retardant technology is mainly applied in the industrial production. A dosage of the flame retardants is about 20%. However, poor compatibility between flame retardants and cellulose leads to some deterioration of viscosity of spinning solution and mechanical property of fibrous materials. The present invention provides flame retardant viscose fibers that have a limiting oxygen index no less than 32.

[0032] A process in ring spinning of the flame retardant yarn of the present invention has following steps:

[0033] A) making composite fibers by mixing or blending flame retardant viscose fibers and high tenacity flame retarding fibers in certain weight ratio.

[0034] B) proceeding a blowing process which includes opening the composite fibers of step A by an opening and picking machine to obtain fibrous rolls by net amount of 350 g/m and length of 25 m.

[0035] C) making card silvers in the net amount of 20 g/5 m by carding the fibrous rolls of step B in use of a carding machine.

[0036] D) making drawing silvers in the net amount of 16 g/10 m by combining three flame retardant viscose fibers and one high tenacity flame retarding pre-drawing fiber by a drawing frame.

[0037] E) making roving yarns in the net amount of 4.0 g/10 m and twist of 3.5/10 cm by stretching the drawing silvers of step D by a roving frame.

[0038] F) proceeding a spinning process, which includes spinning the roving yarns of step E by a compact spinning device to obtain blended compact yarns in the net amount of 1.6 g/100 m and twist of 80/10 cm.

[0039] G) proceeding a heat setting twist process, which includes twisting the blended compact yarns of step F to eliminate internal stress of yarns and stabilize the twist.

[0040] H) proceeding a spooling process, which includes winding the twisted blended compact yarns of step G on a bobbin to obtain yarns.

[0041] A method for preparing the flame retardant finishing viscose fiber is as follows:

[0042] (1) turning viscose fibers to cellulose filaments in a manufacture of viscose fibers, making cellulose tows by entering the cellulose filaments on spinning machine into an acid coagulation bath, and washing the cellulose tows 2˜3 times by clean water;

[0043] (2) soaking the cellulose tows of step (1) in a solution including a flame retardant such as phosphoric acid tris(2-ethylhexyl) ether with a bath ratio of 1:10, and stirring every 30 minutes; wherein the flame retardant is 10% by weight of the cellulose tows, the soaking temperature is 50˜60° C., and the soaking time is 5 hours;

[0044] (3) taking the cellulose tows out of the solution and drying them at a temperature below 180° C. to obtain flame retardant finishing viscose fibers.

[0045] In the above method, the flame retardant may be phosphoric acid tris(2-chloroethyl) ether, phosphoric acid tris(2,3-dichloropropyl) ether), triphosphate(2,3-dibromopropyl) ether, dimethyl methylphosphonate ether, phosphoric acid tris (ethyl butyl) ether, or combination thereof.

[0046] A flame retardancy test for the flame retardant yarn and the fabrics made from the flame retardant yarn:

[0047] Limiting oxygen index (LOI) expresses the minimum concentration of oxygen in a mixture of oxygen and nitrogen as a percentage of volume. In a condition of ASTMG/D2863, materials keep burning under an initial room temperature.

[0048] Combustion residual rate is obtained by calculating material mass before and after combustion for percentage of residual mass. The larger the combustion residual rate is, the less the amount of flammability molecules produced by thermolysis of the material and the better the flame retardancy is.

[0049] For mattress woven from the flame retardant yarn of the present invention, the combustion test is based on the flame retardancy standard of 16 CFR1633. An injection flame burner is used in the combustion test of the surface of the mattress. Evaluation indices includes: (1) thermal release rate peak is less than or equal to 200 kW in a 30-minute test; (2) thermal release amount is less than or equal to 5 MJ in the first 10 minutes; (3) out of at least three samples tested, if any of the three samples fails to meet above both requirements, the product is unqualified.

Example 1

[0050] Based on a total weight of the flame retardant yarn, weigh for 90 wt % of flame retardant viscose fiber and 10 wt % of flame retardant polyester, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 16 yarn-count knitting yarn by a ring spinning frame.

Example 2

[0051] Based on a total weight of the flame retardant yarn, weigh for 80 wt % of flame retardant viscose fiber and 20 wt % of flame retardant polyester, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 21 yarn-count knitting yarn by a ring spinning frame.

Example 3

[0052] Based on a total weight of the flame retardant yarn, weigh for 75 wt % of flame retardant viscose fiber and 25 wt % of flame retardant polyester, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 26 yarn-count knitting yarn by a ring spinning frame.

Example 4

[0053] Based on a total weight of the flame retardant yarn, weigh for 65 wt % of flame retardant viscose fiber and 35 wt % of flame retardant polyester, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 32 yarn-count knitting yarn by a ring spinning frame.

Example 5

[0054] Based on a total weight of the flame retardant yarn, weigh for 80 wt % of flame retardant viscose fiber and 20 wt % of flame retardant finishing viscose fiber, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 16 yarn-count knitting yarn by a ring spinning frame.

Example 6

[0055] Based on a total weight of the flame retardant yarn, weigh for 75 wt % of flame retardant viscose fiber and 25 wt % of flame retardant finishing viscose fiber, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 21 yarn-count knitting yarn by a ring spinning frame.

Example 7

[0056] Based on a total weight of the flame retardant yarn, weigh for 70 wt % of flame retardant viscose fiber and 30 wt % of flame retardant finishing viscose fiber, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 26 yarn-count knitting yarn by a ring spinning frame.

Example 8

[0057] Based on a total weight of the flame retardant yarn, weigh for 60 wt % of flame retardant viscose fiber and 40 wt % of flame retardant finishing viscose fiber, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 32 yarn-count knitting yarn by a ring spinning frame.

Example 9

[0058] Based on a total weight of the flame retardant yarn, weigh for 40 wt % of flame retardant viscose fiber, 10 wt % of flame retardant polyester and 50 wt % of flame retardant finishing viscose fiber, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 16 yarn-count knitting yarn by a ring spinning frame.

Example 10

[0059] Based on a total weight of the flame retardant yarn, weigh for 50 wt % of flame retardant viscose fiber, 10 wt % of flame retardant polyester and 40 wt % of flame retardant finishing viscose fiber, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 21 yarn-count knitting yarn by a ring spinning frame.

Example 11

[0060] Based on a total weight of the flame retardant yarn, weigh for 55 wt % of flame retardant viscose fiber, 10 wt % of flame retardant polyester and 35 wt % of flame retardant finishing viscose fiber, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 26 yarn-count knitting yarn by a ring spinning frame.

Example 12

[0061] Based on a total weight of the flame retardant yarn, weigh for 60 wt % of flame retardant viscose fiber, 10 wt % of flame retardant polyester and 30 wt % of flame retardant finishing viscose fiber, take them into a regular cotton spinning equipment to prepare cotton blended silver. The cotton blended silver is eventually spun into 32 yarn-count knitting yarn by a ring spinning frame.

[0062] The yarns of the above examples 1˜12 are made into cloth and proceeded with performance test. When they are all satisfied with the flame retardancy standard of 16 CFR1633, following performances are tested:

TABLE-US-00001 TABLE 1 performance test tensile breaking Combustion yarn weight, breaking strength, residual count, s g/m.sup.2 force, N cN/dtex capacity, % LOI Example 1 16 320 1250 2.1 27 32 Example 2 21 265 1546 2.3 24 30 Example 3 26 220 2387 2.7 21 28 Example 4 32 180 2530 3.1 18 27 Example 5 16 320 1198 2.0 26 31 Example 6 21 265 1439 2.0 23 30 Example 7 26 220 2156 2.5 19 28 Example 8 32 180 2398 2.9 17 27 Example 9 16 320 1367 2.0 25 29 Example 10 21 265 1689 2.2 23 28 Example 11 26 220 2487 2.7 21 26 Example 12 32 180 2658 2.9 16 27

[0063] According to the Examples 1˜12, it is concluded that when the LOI is larger than 26, the flame retardancy standard of 16 CFR1633 could be achieved. The fabric has breaking strength larger than 2.0 cN/dtex as better performance in tenacity. The higher the weight percentage of the flame retardant viscose fiber is, the higher the LOI or the better the flame-retarding effect is. When the weight percentage of the flame retardant viscose fiber reaches 90% and blended with other yarns, the LOI is 32 and the breaking strength is 2.1 cN/dtex. The higher the weight percentage of the flame retardant polyester is, the better the tenacity of the yarns is. When the weight percentage of the flame retardant polyester reaches 35% and blended with the flame retardant viscose fiber, the breaking strength is 3.1 cN/dtex and the LOI is 27, which performs well in the flame-retarding effect.