JPS5928662B2 - Acrylic construction - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a flame-retardant treatment method for acrylic fiber yarn,
More specifically, when acrylic fiber threads are made flameproof in a flameproofing furnace that has a group of multistage rollers, rollers with a large number of grooves that satisfy three specific formulas are used to prevent the fiber threads from becoming entangled and grooved. overcoming, disordered separation, processing spots,
The present invention relates to a method of flame-retardant treatment to prevent thread breakage.

Carbon fiber has particularly high specific strength and specific modulus of mechanical properties, and is therefore widely used in spacecraft, high-speed rotating bodies, sporting goods, and other applications.

Carbon fibers are produced by making them flame resistant and then carbonizing them.

That is, first, an organic polymer such as recycled cellulose fiber, petroleum-based tar pitch, or acrylonitrile-based fiber is used as a starting material and heated to 200% in an atmosphere of air or other oxidizing gas.
It is produced continuously by making it flameproof at ~500°C and then carbonizing it at 800~2000°C in an inert gas atmosphere such as nitrogen or argon.

In this flameproofing process, various conditions such as temperature, time, tension applied to the fiber yarn to be treated, and structure of the flameproofing furnace are important. As a result of studying the conditions for flame-retardant treatment, we discovered that the structure of the roller grooves has an important relationship with yarn breakage, entanglement of yarns, crossing over, uneven treatment, etc. during flame-retardant treatment. The invention has been achieved.

That is, the present invention has the following gist.

When flame-proofing acrylic fiber yarn in a flame-proofing furnace that has a group of multistage rollers, each yarn is A flame-retardant treatment method for acrylic fibers that separates and makes the fibers independent.

0.15(b/a(0,9o -...
-・-(1)o, 1o(c/a
・・・・・・・・・(2) However, r (h (where a is the width of the top of the double series, b is the width of the bottom of the groove, C is the width between the grooves, and h is the height of the grooves) , d: the apparent diameter of the yarn) According to the present invention, the groove structure satisfies formulas (1) and (2), and the multistage rollers disposed inside and outside of the flameproofing furnace are used to move the fiber yarn to be treated. By using a roller having a large number of grooves that satisfy formula (3) in relation to the diameter of the yarn, which is related to the total denier of Separation and independence are possible, and flame-retardant treatment can be carried out smoothly while preventing yarn cutting, yarn entanglement, crossing over, and uneven treatment.

The groove of the roller used in the present invention is a (width at the top of the groove),
Regarding b (width of the groove bottom), C (width between grooves), h (height of the grooves) (see the drawing above), and d (apparent diameter of the thread), formula (1), ( It is necessary to satisfy all of 2) and (3).

If any one of the formulas is not satisfied, the object of the present invention cannot be achieved (see Comparative Examples below).

The ranges defined by formulas (1), (2), and (3) are limited, and if the ranges are deviated from these ranges, the object of the present invention will not be achieved, as can be seen from the results of the comparative examples described later.

That is, when the value of formula (1) is 0.15 or less, the number of cuts increases, and when it is 0.91 or more, the number of cuts, entanglements, and crossings increases.

If the value of formula (2) is 0.10 or less, the number of cuts is generally
The number of entanglements and overcoming increases.

Although there is no particular limit to the upper limit of formula (2) in relation to achieving the objective of the present invention, it is not economical for the device to unnecessarily increase the width C between the grooves.

Equation (3) is a rewrite of the equation regarding the trapezoidal cross-sectional area of the groove (the ratio of the circular cross-sectional area of the thread to the trapezoidal cross-sectional area of the groove) by rearranging the coefficients.

If the value of equation (3) is out of a predetermined range, the number of times the yarn is cut increases.

Regarding flame resistance, differences in the manufacturing history of the starting fiber yarn, the amount of acrylonitrile component constituting the fiber, the amount of copolymerization component, or the stretching relaxation during fiber molding have a large effect on the shrinkage rate of the fiber. After fully considering these points, it is important to use a roller having a large number of grooves that satisfy formulas (1), (2), and (3) to perform flame-retardant treatment.

For example, the starting material is an acrylic fiber yarn that is copolymerized with acrylonitrile using a relatively large amount of vinyl chloride as a copolymerization component, and the other is when acrylonitrile is used as a starting material using a small amount of methyl acrylate as a copolymerization component. In the case of copolymerized acrylic fiber yarn, even if the temperature inside the flame retardant furnace is the same, the shrinkage rate of the fiber yarn is quite different. A multistage roller must be used that has a large number of grooves that satisfy formulas (1), (2), and (3).

Furthermore, the material of the roller is a corrosive metal,
Even if corrosion-resistant metal is used, if the surface finish of the groove is insufficient, the yarn will be damaged and it will be difficult to obtain a satisfactory flame-resistant yarn. It is preferable that the width between the groove and the groove be uniformly polished and smooth, or that a special surface finishing treatment be applied.

Incidentally, the groove upper part and the groove bottom part can be arbitrarily given an appropriate roundness depending on the type of yarn to be treated.

The present invention will be explained below with reference to examples.

Example 1 100 yarns of 1.5 tenier
rIrIn, b: 2mm, c: 1.5mm, h: 3
The yarn was threaded through a group of multi-stage rollers each having 100 mm grooves and subjected to flameproofing treatment for 3 hours in an oxidizing atmosphere at 250°C.

The results of measuring the number of times the fiber yarn was cut and the number of entanglements in this case are shown in Table 1 below.

Comparative Example 1 a that does not satisfy formulas (1), (2), and (3): 5.5
Flame-retardant treatment was performed using the same yarn and under the same conditions as in Example 1 using a roller having grooves of M, b: 5 grooves, c: o, 5 grooves, and h: 3 grooves.

In this case, the number of times the fiber yarn was cut and the number of times it was entangled were as shown in Table 1.

Examples 2 to 3 200 yarns of 1.5 tenier x 3000 filament acrylic fiber (trademark Bethlon-CA (I3)) were
The yarn was passed through a flameproofing furnace equipped with a group of multistage rollers each having 200 grooves as shown in the table, and flameproofing treatment was carried out in an oxidizing atmosphere at 235° C. for 3 hours.

Table 2 shows the results of measuring the number of times the yarn was cut, entangled, and crossed over into other grooves.

Comparative Example 2 Using rollers with grooves that do not satisfy formula (3), Example 2~
The flame-retardant treatment was carried out under the same conditions as in the same series as No. 3.

The results in this case are shown in Table 2.

Comparative Examples 3 to 14 A roller having grooves that did not satisfy any of formulas (1), (2), and (3) was subjected to flame-retardant treatment under the same conditions as in Example 1.2.

The results in this case are shown in Tables 3 and 4.

As is clear from the comparison between each of the above examples and each comparative example, the desired excellent effects of the present invention can be obtained only when formulas (1), (2), and (3) are satisfied.

[Brief explanation of the drawing]

The figure is a partial sectional view showing one embodiment of the present invention. a: Width at the top of the groove, b: Width at the bottom of the groove, C: Width between the grooves, h: Height of the groove, d: Apparent diameter of the yarn.

Claims (1)

[Claims] 1. When flameproofing acrylic fiber yarn in a flameproofing furnace having a group of multi-stage rollers, the following formulas (1), (2), (3) are used.
) A flame-retardant treatment method for acrylic fibers, which is characterized by separating and making each thread independent using a roller having a large number of grooves that satisfies all of the above. 0.15(b/a(0,90--・・-・(1)0
,10<c/a==<
2)) However, d(h (in the formula, a: Width at the top of the groove, b = Width at the bottom of the groove, C: Width between the grooves, h: Height of the groove, d: Appearance of the thread. diameter).