JPH07300773A - Wholly aromatic polyamide fiber for reinforcing cement - Google Patents

Abstract

PURPOSE:To obtain an aramid fiber for reinforcing cement, having good collecting property and excellent in dispersibility in cement by applying a specific amount of a treating agent containing a specific water-soluble polyester, etc., to the surface of aramid fiber. CONSTITUTION:A treating agent obtained by mixing (A) 60-85wt.% of a water- soluble copolyester obtained by copolymerizing an aromatic dicarboxylic acid, an alkylene glycol, a dicarboxylic acid having SO3M (M is a metal) and/or a polyoxyalkylene glycol with (B) 10-30wt.% of wax having 50-110 deg.C point as wax jointly used with the component A and further, (C) 5-10wt.% of polysiloxane having 3-100cst viscosity at 25 deg.C and preparing the mixture in an emulsion is applied in an amount of 10-30wt.% based on fiber weight to the surface of an aramid fiber in a drawing process of the fiber to provide the objective aramid fiber having good collecting property in cutting into a short fiber and excellent in handleability in processing process and dispersibility in a cement matrix and reinforcing effect.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to wholly aromatic polyamide fibers (hereinafter sometimes referred to as aramid fibers) suitable for cement reinforcement. More specifically, the present invention relates to a wholly aromatic polyamide fiber for cement reinforcement, which has good bundling properties, excellent handleability in a processing step and processing stability, and good dispersibility in cement, and has an excellent reinforcing effect.

[0002]

2. Description of the Related Art Conventionally, in the field of construction or civil engineering, for the purpose of improving the brittleness characteristics of a cement molded body (cement structure), and further for reducing the weight and thinning the cement molded body, a reinforcing aramid fiber is used. It is well known to mix in, and various processing techniques for its use have been proposed. For example, JP-A-62-158149 discloses a method for improving the adhesiveness between aramid fiber and cement by forming a coating layer composed of an alkyl titanate or a titanium chelate compound, and JP-A-63-55142. Discloses a method in which the surface of a fiber is treated with plasma to form a functional group to improve the adhesiveness.

However, the fibers obtained by these methods usually need to be made into short fibers in order to be used as a fiber for cement reinforcement, but since they are inferior in bunching property at the time of production, they easily cause fluffing and deteriorate the quality of the product. The problem of letting
Since aramid fibers have excellent mechanical properties, they are poor in processing stability during cutting, and there is a problem that short fibers are entangled and the dispersibility in cement is reduced. Further, when dispersed in cement, a large amount of air is likely to be entrained at the same time, which makes it difficult for the fiber surface to be wetted by cement, resulting in a decrease in the reinforcing effect.

As a method for solving the problem derived from such short fibers, for example, JP-A-60-215559 discloses a method in which a multifilament yarn is twisted and then bundled with a hydrophobic resin. Japanese Patent Laid-Open No. 62-138347 discloses a method of bundling multifilament yarns with a thermosetting resin, and Japanese Patent Laid-Open No. 63-303837 discloses a method of using flat monofilaments having extremely large single fiber fineness. However, these methods have a problem that the strength and elastic modulus of the aramid fiber cannot be effectively used because the number of fibers in the cement is greatly reduced under the same addition weight. In addition, the hydrophobic resin and thermosetting resin used here need to be dissolved in an organic solvent before use, which causes a problem of deteriorating the working environment. There is a problem that it easily occurs.

On the other hand, Japanese Patent Laid-Open No. 5-295663 discloses that
0.05 to 5% by weight of a polyether ester copolymer composed of dicarboxylic acid / alkylene glycol / polyoxyalkylene glycol is attached to the surface of the carbon fiber,
There has been proposed a method for simultaneously satisfying the fluffing property during yarn making, the workability during cutting, and the dispersibility when dispersed in cement. However, according to our study, even if this method is applied to aramid fiber as it is, aramid fiber is less brittle than carbon fiber and difficult to cut. It was found that the particles were dissociated, the dispersion in the cement became difficult, and the reinforcing effect was insufficient. Such insufficient sizing property can be eliminated by increasing the amount of the polyether ester copolymer attached, but if a large amount of such a treating agent is attached, scum easily occurs and the cement is not easily added. There arises a problem that the dispersibility in the inside also decreases.

[0006]

SUMMARY OF THE INVENTION In view of the drawbacks in the manufacturing process of such cement mixture, the present invention is well focused and has good workability and does not deteriorate in quality until cutting. An object of the present invention is to provide a wholly aromatic polyamide fiber for cement reinforcement, which has good dispersibility when dispersed in a cement matrix and has an excellent reinforcing effect.

[0007]

The above object of the present invention is to provide a treating agent satisfying the following (A) and (B) on the surface of a wholly aromatic polyamide fiber by 10 to 30% by weight based on the weight of the fiber. Is achieved by a wholly aromatic polyamide fiber for cement reinforcement. (A) Content of the water-soluble copolyester obtained by copolymerizing an aromatic dicarboxylic acid, an alkylene glycol, and a dicarboxylic acid having an SO ₃ M group (M represents a metal) and / or polyoxyalkylene glycol is 60 to 85.
% By weight, (B) the content of the wax having a melting point of 50 to 110 ° C. is 10 to 30% by weight, and the wholly aromatic polyamide fiber targeted by the present invention means an aromatic dicarboxylic acid and an aromatic diamine, or an aromatic compound. Polyamides composed of group aminocarboxylic acids, and fibers composed of copolyamides thereof, are particularly excellent in strength and elastic modulus and have a high reinforcing effect. Therefore, poly-p-phenylene terephthalamide fibers, copoly- Para-oriented aramid fibers such as p-phenylene- (3,4'-oxydiphenyl) terephthalamide fiber (Technora: manufactured by Teijin Ltd.) are preferable.

If the monofilament fineness of the aramid fiber is too small, manufacturing problems tend to occur and the reinforcing effect tends to be insufficient. On the other hand, since aramid fibers are generally wet-spun, it is difficult to stably produce aramid fibers having a large fineness. Therefore, the range is usually 0.5 to 5 denier, preferably 1 to 3 denier. On the other hand, the total fineness of the aramid fiber is not particularly limited, but if it is too small, the effect of bundling the single fibers becomes small, and conversely if it becomes too large, the alignment unevenness of the single fibers is likely to occur, so that it is 500- 3000 denier, especially 1000-
About 2000 denier is preferable.

In the present invention, the above-mentioned wholly aromatic polyamide fiber contains (A) a water-soluble copolyester and (B) a wax-containing treatment agent, preferably (C) a polysiloxane-containing treatment agent. It is important to attach.

The water-soluble polyester (A) is an aromatic dicarboxylic acid, alkylene glycol or SO ₃
Although it is composed of a dicarboxylic acid having a M group (M is a metal ion) and / or polyoxyalkylene glycol, it may contain a small amount of other copolymerization component within a range not impairing the object of the present invention.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, and 4,4'-oxybenzoic acid. Among them, terephthalic acid and isophthalic acid have the ability to bundle fibers. It is preferable to increase the dispersibility in the cement as well as to increase the dispersibility. Especially, the molar ratio of terephthalic acid / isophthalic acid is 65
It is desirable to be in the range of / 5 to 50/50.

Examples of the alkylene glycol include those having 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, and diethylene glycol.
Of these, ethylene glycol and diethylene glycol are preferable.

Examples of the dicarboxylic acid having an SO ₃ M group (M is a metal) include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid and other sulfonic acids. Examples of the metal salts include, and examples of the metal salts include alkali metal salts of sodium, potassium, lithium and the like. Of these, particularly preferred is 5-sodium sulfoisophthalic acid. The copolymerization ratio of the dicarboxylic acid having such SO ₃ M group is 40 mol% or less, preferably 5 to 20 mol% based on the total dicarboxylic acid components of the copolyester, and 40 mol% is desirable. If it exceeds the above range, the melt viscosity is remarkably increased, and it becomes difficult to obtain a polymer having a desired degree of polymerization by the melt polymerization method, which is not preferable.

Further, as the polyoxyalkylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene glycol.
Examples thereof include polyoxypropylene glycol copolymers, and among them, polyoxyethylene glycol is preferable. These polyoxyalkylene glycols are
One hydroxyl group may be blocked with an ether bond,
For example, monomethyl ether, monoethyl ether, monophenyl ether can be used. The average molecular weight of the polyoxyalkylene glycol is usually 500 to
Although it is 12000, it is particularly preferably 1000 to 6000. The copolymerization amount is 20 to 90% by weight, preferably 30 to 8% by weight based on the weight of the produced copolymerized polyether.
0% by weight is desirable, and when the amount of copolymerization is small, the water solubility tends to decrease and the dispersibility of the obtained fiber in cement tends to decrease. Is likely to run short.

If the intrinsic viscosity of the copolymerized polyester (measured in o-chlorophenol at 25 ° C.) is too high, the viscosity of the treating agent becomes too high, and the process stability when the treating agent adheres decreases. It is not desirable, and on the other hand, if it is too small, the cohesive force of the treatment agent film is reduced and it becomes difficult to achieve the object of the present invention. The term "water-soluble" as used in the present invention is not limited to being completely water-soluble, as long as it can be finely dispersed in water.

As the wax (B) which is another component of the treating agent used in the present invention, any wax can be used as long as it has a melting point in the range of 50 to 110 ° C. Among them, it is water-insoluble. Examples thereof include natural waxes such as carnauba wax, cotton wax, wood wax, beeswax, wool wax, montan wax, paraffin wax, and microcrystal wax, and synthetic waxes such as polyethylene wax. Further, these waxes may be subjected to an oxidation treatment, and an oxidized polyethylene wax, an oxidized microcristan wax or the like may be used. When the melting point of these waxes is less than 50 ° C., the tackiness of the treatment agent increases and the smoothing effect also decreases, which causes fuzz and is not preferable. On the other hand, when the temperature exceeds 110 ° C, the brittleness of the treatment agent film increases and scum easily occurs due to rubbing with the guides, and the focusing property at the time of cutting into short fibers also deteriorates to cause fiber dispersion. It is not preferable because

As the polysiloxane (C) which is preferably used in combination with the above-mentioned components A and B, any polysiloxane (C) having a viscosity at 25 ° C. of 5 to 100 centistokes can be used. Dimethylsiloxane or modified polysiloxane modified with it, such as phenyl modified polysiloxane, aminoalkyl modified polysiloxane, epoxy modified polysiloxane, polyoxyalkylene modified polysiloxane, and fatty acid modified polysiloxane is preferably used. Here, if a viscosity of less than 5 centistokes is used, it is difficult to obtain the effect of using polysiloxane together. Conversely, if a viscosity of more than 100 centistokes is used, the viscosity of the treating agent becomes high and the effect of suppressing fluff is obtained. Tends to decrease.

By combining the above components,
In order to obtain the intended effect of the present invention, it is important that the component A is the main component of the treating agent, and the content thereof is 60.
˜85% by weight, preferably 60 to 80% by weight, while the content of component B should be 10 to 30% by weight, preferably 15 to 25% by weight. When the content of the component A is less than 60% by weight, the mechanical properties of the treatment agent film are deteriorated, so that the sizing property when cut into short fibers is insufficient. On the other hand, when it exceeds 85% by weight, dispersibility when dispersed in cement becomes insufficient, which is not preferable.

On the other hand, when the content of the component B is less than 10% by weight, not only the dispersibility in dispersing in the cement becomes insufficient, but also fluff and scum are caused when the treating agent is attached to the fiber. It tends to occur. On the other hand, if the amount exceeds 30% by weight, the mechanical properties of the treatment agent coating become insufficient, and the bundle focusing property when cutting short fibers becomes insufficient.

Next, the content of the component C, which is preferably used in combination with the above components A and B, is preferably in the range of 5 to 10% by weight. By selecting the content of the polysiloxane in this range, the effect of suppressing the generation of scum and fluff when applying the treatment agent is improved, and the effect of cement reinforcement is improved.

Other components such as an emulsifier, an antistatic agent, an antioxidant, a compatibilizer, a stability improver and the like are appropriately added to the treatment agent of the present invention within the range not impairing the object of the present invention. be able to. However, it is preferable to keep these components to the minimum necessary.

In order to attach the treatment agent described above to the aramid fiber, an emulsion emulsified in water may be attached by a conventionally known method. That is, for example, poly-
In the case of paraphenylene- (3,4'-oxydiphenylene) terephthalamide fiber, a roller system, a spray system,
It may be adhered by a dipping method or the like, and usually, a roller type oil supply method is adopted subsequent to the stretching step.

The amount of the treating agent deposited on the aramid fiber is 10 to 30% by weight, preferably 15 to 2% by weight based on the weight of the fiber.
It is important to be in the range of 5% by weight. Since the aramid fiber has very good mechanical properties, the adhesion amount is 10
If the amount is less than 5% by weight, the fiber length is 3 for cement reinforcement.
When cut into ~ 12 mm, the focusing effect is insufficient and the resulting short fibers are entangled, so that a sufficient reinforcing effect cannot be obtained. On the other hand, if it exceeds 30% by weight, an excessive amount of the treating agent will contaminate the yarn conductor, and the dispersibility in the cement will be deteriorated, whereby a sufficient reinforcing effect cannot be obtained, which is not preferable.

The aramid fiber to which the treatment agent is attached is dried and then wound, and the drying method may be a hot plate method, a heat roller method, an infrared method or the like. In addition, since the treatment agent of the present invention is less likely to adhere to a metal surface such as a roller even during drying, a contact-type drying method is a preferable method in terms of efficient drying, and the drying temperature (roller temperature) is It is preferably about 120 to 200 ° C.

[0025]

The wholly aromatic polyamide fiber of the present invention has a sufficient sizing property due to the treatment agent containing the above-mentioned water-soluble polyester as a main component adhered thereto. It has good process stability and is easy to handle up to the step of forming fibers, and the obtained short fibers have no fluff and no entanglement between single fibers. Moreover, since the short fibers obtained by cutting are bundled with the water-soluble polyester, not only the workability in dispersing them in the cement is good, but also it becomes possible to easily disperse them in the cement. . In addition, since the treatment agent contains wax in addition to the water-soluble polyester, the detailed reason for this is unknown, but the amount of the treatment agent attached is increased to the extent that the wholly aromatic polyamide fibers can be bundled. However, when it is dispersed in cement, it can be dispersed up to the level of single fiber, and a sufficient reinforcing effect is achieved.

It is presumed that the treatment agent according to the present invention has a low tackiness during drying and a small friction resistance, and scum is less likely to be deposited on the yarn guides and rollers even in the manufacturing process, so that the treatment package is not easily removed. As a result of the good unwinding property of the fiber, it also has a feature that a product of extremely good quality can be stably manufactured.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, each evaluation item in the examples was measured according to the following methods. (1) Scum Two hours after the start of application of the treatment agent, the scum attached to the heating roller heated to 170 ° C. was visually determined and evaluated according to the following criteria. ◯: Good with almost no scum. Δ: The surface of the roller is slightly whitish and is judged as scum. X: A large amount of tacky or white powdery substances are recognized.

(2) Fuzz 10 rolls of raw yarn are wound, each with a length of 10^FourThe number of fluffs in m
It was counted and evaluated according to the following criteria. ◯: Number of fluff 0 to 3/10^Fivem, Δ: 4 to 9 pieces / 10
^Fivem, x: 10 pieces / 10 ^Fivem or more

(3) Bundling property The aramid fiber of 1500 denier / 1000 filament to which the treating agent was applied was guillotine cutter and the fiber length was 6 m.
It cut | disconnected to m and measured the maximum width (mm) of the cut end surface of the obtained short fiber bundle. In addition, 20 samples were measured and the average value was calculated.

(4) Dispersibility To 100 parts by weight of Portland cement (manufactured by Tokuyama Soda Co., Ltd.), 2 parts by weight of aramid fiber having a cut length of 6 mm and 1 part by weight of methyl cellulose and 30 parts of water to which a treating agent is attached.
An omni mixer was used to mix 5 parts by weight for 5 minutes. 50 g of the obtained cement mixture was sampled and spread on a 50-mesh wire mesh to a thickness of 2 to 3 cm, and then a 50-mesh wire mesh was placed on the upper part, and then shower water was sprayed to allow the cement to flow out, and then onto the wire mesh. The state of the remaining fibers was visually evaluated. ◯: Almost no fiber lumps or defective opening. Δ: A lump of fibers and a defective opening part are partially observed. X: A large amount of fiber lumps and defective opening are observed.

(5) Reinforcing effect (bending strength) The cement mixture obtained by the above method was used in an amount of 4 cm × 4 cm × 16.
cm mold and left at room temperature for 24 hours to obtain a test sample. This sample was left to stand at room temperature for 4 weeks for curing, and then the breaking strength (kg / cm ² ) was measured by a center loading method with a span length of 10 cm.

[Reference Example] Dimethyl terephthalate (DM
T) 16.1 parts by weight, dimethyl isophthalate (DMI)
2.0 parts by weight, 17.2 parts by weight of ethylene glycol (EG), and 0.0002 parts by weight of calcium acetate as a transesterification reaction catalyst were charged into a reactor equipped with a stirrer, a rectification column and a methanol distillation condenser, and 140 ° C. To 230 ° C. to conduct a transesterification reaction while distilling methanol generated as a result of the reaction out of the system, and then 0.0001 part by weight of orthophosphoric acid and 0.000 of antimony trioxide.
2 parts by weight, 5-sodium sulfoisophthalic acid glycol ester (SI) 3.7 parts by weight and average molecular weight 30
49.0 parts by weight of polyethylene glycol (PEG) of 00 was added, the temperature was gradually raised from 230 ° C. to 275 ° C., and the polycondensation reaction was carried out while lowering the pressure from normal pressure to a high vacuum of 0.5 mmHg. The reaction was completed in 100 minutes of the total polycondensation reaction time, taken out from the reactor, and then cooled and solidified to obtain a white water-soluble copolyester (I).

[Example 1] The dicarboxylic acid component was terephthalic acid, and the diamine component was paraphenylenediamine.
1500 obtained by spinning and drawing a wholly aromatic polyamide which is 4'-diaminodiphenyl ether (molar ratio 1/1)
Denier / 1000 filament, strength 29.5g /
d, elongation of 4.47%, elastic modulus of 660 g / d, and a 25 wt% aqueous emulsion of the treating agent shown in Table 1,
The treatment agent active ingredient was adhered by a roller method so as to be 15% by weight based on the weight of the fiber, and then it was wound around a heating roller having a diameter of 20 mm heated at 170 ° C. for 20 times and dried, and at a speed of 400 m / min. I wound up. Table 2 shows the evaluation results of the obtained fibers.

[0034]

[Table 1]

[0035]

[Table 2]

[Embodiment 2] No. 1 of the first embodiment. The same procedure as in Example 1 was carried out except that the oil agents 1 and 2 were used and the amount of the oil agent was changed as shown in Table 3. The results are shown in Table 3.

[0037]

[Table 3]

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Claims (2)

[Claims] 1. A cement reinforcing agent, wherein a treating agent satisfying the following (A) and (B) is adhered to the surface of wholly aromatic polyamide fiber in an amount of 10 to 30% by weight based on the weight of the fiber. All aromatic polyamide fiber. (A) Content of the water-soluble copolyester obtained by copolymerizing an aromatic dicarboxylic acid, an alkylene glycol, and a dicarboxylic acid having an SO ₃ M group (M represents a metal) and / or polyoxyalkylene glycol is 60 to 85.
% By weight (B) Content of wax having a melting point of 50 to 110 ° C. is 10 to 30% by weight 2. The wholly aromatic polyamide fiber for cement reinforcement according to claim 1, wherein the treating agent satisfies the following (C). (C) Content of polysiloxane having a viscosity at 25 ° C. of 3 to 100 centistokes of 5 to 10% by weight