JPS59163425A - Surface modification of synthetic fiber - Google Patents

Abstract

PURPOSE:To prevent the mutual welding of the filaments of synthetic fiber exhibiting weldability in the heat elongation and heat-treatment process, by applying a mixture of a hydrophobic colloid and a colloid of inorganic compound forming hydrophilic gel to the surface of the fiber, and drying the applied colloid mixture. CONSTITUTION:A mixture of a colloid of an inorganic compound forming hydrophilic gel (preferably a silicate compound, especially hydrated aluminum silicate or magnesium fluorosilicate) and a hydrophobic colloid (preferably colloidal graphite) is applied to the surface of a synthetic fiber weldable in heat-elongation and/or heat-treatment process (preferably an aromatic copolyamide) by dipping, and the mixture is dried to obtain the surface-modified fiber. The mutual welding of filaments can be prevented effectively even if the fiber is composed of a large number of filaments.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for surface modification of synthetic fibers. More specifically, the present invention relates to a method of preventing fusion by modifying the surface of synthetic fibers that cause fusion between single and single molecules during hot drawing and/or heat treatment.

In recent years, the demands on fibers have become more sophisticated, and in response to the demands for high strength and high modulus, various new materials have been developed and studied. For some of them, high-magnification stretching at high temperatures or a heat treatment process at high temperatures is applied to achieve high performance, and undesirable fusion between single filaments occurs during this process. In other words, some fibers that have fusibility during drawing (or heat treatment) exhibit high performance as single filaments, but when multifilament fiber bundles are drawn and/or heat treated in the usual manner, There are many cases in which the performance as an aggregate is significantly impaired when the fusion between single yarns is significant L<-1.

As a method of preventing the above-mentioned single filament fusion, the present inventors previously proposed a method of applying a hydrated gel-forming inorganic compound to the surface of the ffl male during hot stretching and/or heat treatment (
(Japanese Patent Application No. 56-151944) e However, even with this method, a problem has been encountered in that as the number of single yarns constituting the fiber bundle increases, the effect of preventing single yarn fusion decreases. As a result of our extensive research into the cause of this, we found that when an aqueous dispersion of a hydrated gel-forming inorganic compound is applied to fibers and then dried, the water content on the fibers decreases and the gel-forming inorganic compounds are removed. As a result of agglomerating, forming coarse particles, and adhering to the fiber surface as coarse particles, the compound cannot uniformly cover the fiber surface, and this phenomenon of non-uniform adhesion increases the number of single filaments constituting the fiber bundle. We found that it becomes more noticeable as time goes on.

Purpose of the Invention Based on the above findings, the present inventors have discovered that after applying an aqueous dispersion of a hydrophilic gel-forming inorganic compound to fibers, in the process of drying and reducing the water content, the concentration of the inorganic compound decreases. As a result of intensive research, the present invention was developed in order to provide a method in which the compound does not aggregate at most, can be attached to the fiber surface in the form of fine particles, and can effectively prevent fusion between single yarns even when the number of single yarns is large. has been reached.

Structure of the Invention That is, the present invention provides a method of applying a mixture of a hydrophilic gel-forming inorganic compound colloid and a hydrophobic colloid to the surface of a fiber having fusibility during hot drawing and/or heat treatment, and then drying the mixture. This method is characterized by

Here, the hydrophilic gel-forming inorganic compound refers to a compound such as hydrated aluminum silicate A that forms a gel by containing 5 times or more water than the inorganic compound when calculated without water (swelling with hydration swelling property). Examples of the hydrophilic gel-forming inorganic compound colloids include colloidal silica made of finely divided silica and alumina sol made of finely divided alumina. Furthermore, a hydrophobic colloid is an aqueous dispersion system of finely divided inorganic particles that have a weak affinity for water, such as colloidal graphite.

Colloid of hydrophilic gel-forming inorganic compound (hydrophilic colloid)
When only M-fibers are applied to the fibers and then dried, as mentioned earlier, the inorganic compounds coagulate during the drying process and become coarse particles of secondary aggregates that are deposited unevenly on the fiber surface. However, when the number of component yarns in a fiber bundle increases, there is a problem in that the effect of preventing fusion during hot drawing or heat treatment decreases significantly.Also, even if only hydrophobic colloid is used, inorganic σ
Therefore, in the present invention, in order to suppress the coagulation of the hydrophilic gel-forming amorphous compound and uniformly adhere the compound to the fiber surface in the form of fine particles, the hydrophilic gel-forming amorphous compound is A colloid and a hydrophobic colloid are mixed, and the hydrophilic colloid protects the fine particles constituting the hydrophobic colloid, stabilizing the hydrophobic colloid, and at the same time reducing the charge used by the hydrophilic colloid for coagulation.

In the present invention, when mixing a hydrophilic colloid and a hydrophobic colloid, the respective aqueous colloids may be prepared and then mixed, or the hydrophilic gel-forming inorganic compound may be dispersed in the hydrophobic colloid. Fine particles constituting the hydrophobic colloid may be dispersed in the hydrophilic colloid.

Moreover, hydrophilic colloid and hydrophobic colloid are respectively −
It does not have to consist only of component compounds, but may be a mixture of two or more kinds of compounds having similar functions. Moreover, a colloidalization aid may be included if necessary.

In the present invention, the mixing ratio of hydrophilic colloid and hydrophobic colloid may be any ratio as long as the entire mixing system is stable.
Preferably, the ratio of the hydrophilic gel-forming inorganic compound to the constituent fine particles of the hydrophobic colloid is such that the ratio of the respective constituent active ingredients is 1:1 to 10,00.
A range of 0:1 is preferred.

In the present invention, as a method for applying a mixture of a hydrophilic colloid and a hydrophobic colloid to the fiber surface, it is preferable to immerse the fiber in a mixed solution while running the fiber.

The amount of the inorganic compound added to the fibers is 0.05 to 5% by weight, preferably 0.2%, based on the weight of the fibers.
~2.0% by weight is applied.

Synthetic fibers to which the method of the present invention can be applied include all those that exhibit fusion properties during hot drawing and/or freezing heat treatment. Here, fusion property refers to the property of forming a fused portion between fibers when a plurality of fibers are heat-stretched and/or heat-treated as a fiber bundle. Examples of fibers to which the method of the present invention is applied include polyethylene and polypropylene.

Examples include fibers such as thermoplastic polymers such as nylon and polyester, or partially cured thermosetting resins.

Further, as the fiber to which the method of the present invention is applied, synthetic fiber materials made of the following polymers, which have been recently developed and researched as high strength and high modulus fibers, are suitable.

a) The following repeating unit: -NRI -A r) -NR2-CO-A rz -
Aromatic copolyamide composed of CO- and/or -NR3-AR3-CO-.

Such aromatic copolyamides include, for example, aromatic residues (p-
Fully aromatic polyamide K1,3.4'-
diphenyl ether, 4,4'-diphenyl ether,
Aromatics with improved stretchability when formed into fibers by copolymerizing m-phenylene, etc., or by substituting some of the hydrogen atoms of aromatic residues with norogen atoms and/or lower alkyl groups. Among them, Ar1゜A rz , Arl is 80 or more mole, and the structural unit (6) has a mole of 10 to 4.
0 and all of R1, R2, and B-B are hydrogen atoms.

b) The following four repeating units -NR2-Ar, -Co-NH-NH-(C)NR2A
r2 NR3(D) -NR4-A r3-c O-(E)-co-p, r
, -co-CF) Aromatic copolyamide hydrazide.

Examples of such aromatic copolyamide hydrazide include aromatic copolyamide hydrazide in which hydrazide bonds are introduced into a fully aromatic polyamide consisting of an aromatic residue having straight and/or twisted parallel axis bonding hands. , especially the aforementioned Ar4, Ar2, Ar3,
80 moles φ or more of Ar4 are p-phenylene residues,
In addition, it is preferable that RI and R21R31R4 are all hydrogen atoms.

C) The following repeating unit - N Ar) CC (G) o / [Here, Arl and Arz are the same as in (b) above]
An aromatic oxadiazole/methyl hydracit copolymer consisting of:

d) a thermoplastic polymer capable of forming optically anisotropic melts;
For example, fully aromatic polyester diaromatic polyazomethine.

Effects of the Invention In order for the fibers made of the polymers (,) to (c) above to exhibit sufficient performance, it is necessary to heat them at a high temperature (e.g., a temperature of 300°C or higher) that causes fusion between the fibers. Stretching is necessary, and in order to obtain sufficiently high strength in the fibers of (d), heat treatment at a high temperature and for a relatively long period of time is necessary to form fusion between the fibers.

Furthermore, when a thermoplastic fiber such as polyethylene is drawn at a high draw ratio (10 to 50 times) to obtain a high-strength, high-modulus fiber, if the drawing operation is performed on a multifilament fiber aggregate, Fusion between single yarns is unavoidable.

By applying the method of the present invention to these fibers that exhibit fusion properties during hot drawing and/or heat treatment, 1. fusion between single yarns can be prevented or significantly reduced without impairing fiber performance. This makes it possible to obtain a great effect, especially when the number of single yarns constituting the fiber bundle is large. Such effects will become clearer from the experimental results shown in the following Examples and Comparative Examples.

Example The method of the present invention will be explained below with reference to Examples.

The main characteristic values used in the following examples are as follows.

(1) Intrinsic viscosity IV of the polymer
viscosity) using an Ostwald type viscosity tube,
When the flow time of only the solvent is to (seconds), the flow time of the dilute polymer solution is t (seconds), and the polymer concentration in the dilute solution is (f/de), it is expressed as follows. Unless otherwise specified, solvent is 97.5%
Sulfuric acid, C=0.5? /de and measure at 30°C.

(2) Tensile properties of #fibers Using an Instron tensile tester, the elongation curve is measured in an atmosphere of 20° C. and 65φRH with an initial length of 250 and a tensile speed of 10 an/min. From this, strength (4/de), elongation (
%) and Young's modulus (f/cle).

(3) Fusing degree f The value obtained by dividing the number of single filaments that should originally exist in the yarn by the number of filaments actually counted in the yarn after drawing or heat treatment is used. That is, it shows how many single filaments on average are fused together to form one filament after drawing or heat treatment. Measurements were taken at five locations, and the average value was taken as f.

Example 1 An aromatic copolyamide of IV-3,1 composed of the following monomer unit -HN-(C>-NH-25) was converted into N-methyl-2-pyrrolidone (NMP) containing CaCZ2. A polymer solution of 6% by weight dissolved in
It was extruded from a nozzle with a hole diameter of 0.2 to 1000 at a discharge rate of 940 f/min. After running about 10 hours in the air, 5
It was coagulated in a coagulation bath of N-methyl-pyrrolidone/water (30,/70% by weight) at 0°C, withdrawn at a speed of 30 m/min and subsequently washed in a water bath at 50°C. The water-washed yarn is immersed in a solution containing 0.5 water dispersion colloid of hydrated aluminum silicate (10 parts) and 2 parts of colloidal graphite (graphite content 22%), squeezed with a squeezing roller, and then wound around a drying roller. Swirled to dry.

The amount of fine particles attached as a solid content was about 0.6% based on the weight of the dry yarn. Continuing, 5o.

It was stretched 12 times on a hot plate at 0.degree. C., coated with an oil agent, and then wound up. The physical properties of the obtained yarn are shown in Table 1. In the comparative example, 0.5% of hydrated aluminum spherate was mixed with no colloidal graphite.
% when using only water-dispersed colloid.

Table 1 Example 2 In Example 1, instead of the water-dispersed colloid of hydrated aluminum silicate, a water-dispersed colloid of magnesium fluorosilicate,
Colloidal silica and alumina sol were used. The results are shown in Table 2.

Table 2 In the above Table 2, () indicates the degree of fusion when colloidal m-lead is not mixed and used.

Examples 3-5. Comparative Examples 3 to 5 The polymer solutions shown in Table 3 were spun and drawn according to Example IK. However, in each example, the discharge amount was adjusted to match the final denier.

The amount of fine particles deposited as a solid content was about 0.5 inch based on the weight of the dry yarn. Table 4 below shows the drawing conditions and properties of the drawn yarn. Further, for the purpose of comparison, a case where only a hydrated aluminum silicate water-dispersed colloid is used is shown as a comparative example.

All of the fibers in the comparative examples lacked flexibility due to fusion between single filaments.

Example 6 The following structural unit empty IV = 2.1 (50% in p-chlorophenol)
The spinning temperature of fully aromatic polyester (measured in °C) is 330 °C.
s from a spinneret with a hole diameter of 0.5 mm and a number of holes of 50,
Push out into the air with s f /-2507? It was wound up at i/min.

The obtained thread was placed in 10% of an aqueous dispersion of aluminum magnesium silicate with colloidal graphite (22% for 1 part of graphite).
The fish were immersed in a mixture of two parts, dried, and then rolled up into a skein.

1 hour at 250°C in a nitrogen stream while tightly rolled in a skein.
1 hour at 0℃, 1 hour at 270℃.

Heat treatment was performed at 280°C for 1 hour, at 290°C for 1 hour, and at 300°C for 3 hours.

The properties of the yarn before and after heat treatment are shown in Table 5 below.

Table 5 Comparative Example 6 The yarn was spun and heat treated in the same manner as in Example 6 except that colloidal graphite was not used in the mixture, and the degree of fusion f of the obtained yarn was 2.
．． 5, which was extremely poor quality.

Patent applicant Teijin Ltd.

Claims (1)

[Scope of Claims] (1) Applying a mixture of a hydrophilic gel-forming motive compound colloid and a hydrophobic colloid to the surface of a synthetic fiber that has fusibility during hot drawing and/or heat treatment, and then drying. A surface modification method for synthetic fibers with % characteristics. (2) The method for surface modification of synthetic fibers according to claim 11, in which the hydrophobic colloid is colloidal graphite. (3) Claim 1, in which the hydrophilic gel-forming inorganic compound is a silicate compound, or The method for surface modification of synthetic fibers according to claim (2). (4) Claims (1) or (2) wherein the hydrophilic gel-forming inorganic compound is hydrated aluminum silicate or magnesium fluorosilicate. ) The method for surface modification of synthetic fibers according to claim 1. (5) The synthesis according to claim 1 or 2, wherein the colloid of the hydrophilic gel-forming inorganic compound is colloidal alumina or alumina sol. Method for surface modification of fibers. (6) Synthetic fibers contain the following repeating unit -NRI-A
rl-NR2-Co-Ar2-Co- and/or NR3Arg co- Aromatic copolyamide fibers according to any one of claims (1) to (5) Method for surface modification of synthetic fibers. (7) 80 or more moles of Arl, Ar2, Ar3 are the following aromatic residues, and the amount of the structural unit (B) is 10 to 40 moles. The method for surface modification of synthetic fibers according to claim (6), the surface of synthetic fibers according to claim (6) or claim (7), in which (81R+ 1. "21" are all hydrogen atoms) Modification method. (9) Synthetic fibers are repeatedly disposed of as follows - NRIAr
1co NHNH(C) -NR2-A C2-NR3-(D)-NR4-A
Any one of claims (1) to (5) which is a fiber of aromatic copolyamide hydrazide consisting of C3-Co-(E)-cO-A C4-Co-(F) The method for surface modification of synthetic fibers described. (II Arl, Ar2, Arz, Ar
9. The method for surface modification of synthetic fibers according to claim 9, wherein 80 or more moles of 4 are p-phenylene residues. αl) A method for surface modification of synthetic fibers according to claim 9 or 10, wherein R1+ R2r R3+ R4 are all hydrogen atoms. Claims Nos. C1+ to (
5) The method for surface modification of synthetic fibers according to any one of the above. (13) More than 80 mol of Ar, , Ar2 is p
- 1 method for surface modification of synthetic fibers according to claim 02, which is a phenylene residue. 0・``l The synthetic fiber is made of a thermoplastic polymer capable of forming an optically anisotropic melt. (1) A method for surface modification of synthetic fibers according to claim 14, in which the thermoplastic polymer is a wholly aromatic polyester. A method for surface modification of synthetic fibers as described in scope 1.