JPH08311768A - Polyester fiber excellent in adhesion - Google Patents

Abstract

PURPOSE: To produce polyester fibers which can increase the adhesion between fibers and rubber and are suitable for rubber composites by applying a compound having isocyanuric acid skeleton and dihydroxypropyl groups to polyester fibers. CONSTITUTION: An aqueous emulsion containing a compound having isocyanuric acid skeletons and at least one of 2,3-dihydroxypropyl group in its molecular structure represented by formula I [Z is CH2 CH2 COO, CH2 CHO, CH2 CH(OH)CH2 O, CH2 CH(OH)CH2 S; X1 , X2 are each Z.CH2 (OH)CH2 OH, H, methyl, CH2 CH= CH2 , CH2 CH2 OH or CH2 CH2 COOH], preferably tris(2,3-dihydroxypropyl) isocyanurate of formula II is applied to polyester fibers in an amount of 0.2-20wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber suitable for reinforcing rubber composites such as tire cords, belts and hoses. More specifically, the present invention relates to a polyester fiber treated with a compound different from an epoxy compound or an isocyanate compound which has been widely used in the past and having improved adhesion between the fiber and rubber.

[0002]

2. Description of the Related Art Polyester fibers represented by polyethylene terephthalate fibers generally have physical properties such as excellent strength, Young's modulus, dimensional stability and fatigue resistance. It is widely used as a reinforcing fiber for rubber composites such as hoses.

However, the polyester fiber is nylon 6,
Compared with polyamide fibers such as nylon 6.6, even when treated with resorcin / formalin / rubber latex (RFL), which is widely used for bonding rubber and fiber, adhesion to rubber is poor and polyester The excellent mechanical properties of the fiber cannot be fully exerted. This is mainly because the polyester fiber surface is inactive, the affinity and reactivity with RFL are poor, and the hydrogen bond ability of the ester bond in the polyester is smaller than the hydrogen bond ability of the amide bond of nylon. It is believed that. Therefore, the surface of the polyester fiber is chemically or physically modified to introduce a functional group such as a hydroxyl group into the surface of the fiber to impart reactivity with RFL, or to have reactivity with RFL and at the same time the polyester fiber. A method of imparting adhesiveness by treating with a highly reactive substance such as an epoxy compound or an isocyanate compound having affinity for both is put to practical use.

Recently, however, there has been a concern that epoxy compounds may affect health, for example, US Pat. No. 443.
No. 8178 proposes a method using a non-epoxy compound such as epichlorohydrin ether. However, since this compound easily forms an epoxy when heated in the presence of an alkali catalyst, it cannot be said to be sufficient in safety during the treatment process. On the other hand, in the case of an isocyanate compound, in order to use it as it is, it must be a solvent system, and in order to use it in an aqueous system, blocking of the isocyanate group is required, and it is pointed out that it is complicated. There is.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to eliminate the toxicity which has been a concern in the conventional treatment with an epoxy compound or an isocyanate compound, and It is to provide a polyester fiber having good adhesion to rubbers.

[0006]

The above object of the present invention is to provide a polyester fiber having the following general formula (I) having an isocyanuric acid skeleton and at least one 2,3-dihydroxypropyl group in its molecular structure. This is achieved by attaching a treatment agent containing the compound (A) represented by Chemical formula 3).

[0007]

Embedded image

The polyester fiber in the present invention means the following general formula (Formula 4).

[0009]

[Chemical 4]

A polyester having a repeating unit represented by the following as a main repeating unit, and among them, a polyester having a main glycol component of at least one glycol selected from ethylene glycol and tetramethylene glycol is preferable. Specific polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like. The molecular weight of such polyester, the terminal carboxyl group concentration, etc. are arbitrary, and the denier of the fiber, the number of filaments, the cross-sectional shape,
The physical properties of the fiber, the fine structure, and the presence or absence of additives are optional, and the present invention is not limited thereto.

In the present invention, a compound (A) represented by the following general formula (Formula 5) having an isocyanuric acid skeleton and at least one 2,3-dihydroxypropyl group in the molecular structure is added to the polyester fiber. It is important that the are attached.

[0012]

Embedded image

In the formula, Z is either a direct bond or a compound represented by the following formula (Formula 6), and the direct bond is preferable.

[0014]

[Chemical 6]

Further, X ₁ and X ₂ are either represented by the following formula (Formula 7), and they may be different from each other or may be the same.

[0016]

[Chemical 7]

The compound (A) preferably used is, for example, tris (2,3-dihydroxypropyl).
Isocyanurate, bis (2,3-dihydroxypropyl) -allyl isocyanurate, 2,3-dihydroxypropyl-diallyl isocyanurate, bis (2,3-
Dihydroxypropyl) -2-hydroxyethyl isocyanurate, 2,3-dihydroxypropyl-bis (2
-Hydroxyethyl) isocyanurate, bis (2,3
-Dihydroxypropyl) -2-carboxyethyl isocyanurate, 2,3-dihydroxypropyl-bis (2-carboxyethyl) isocyanurate, bis (2,3-dihydroxypropyl) -2-hydroxy-
3-stearoyloxypropyl isocyanurate, bis (2,3-dihydroxypropyl) -2-hydroxy-3-stearoxypropyl isocyanurate, tris (3- (2 ', 3'-dihydroxypropoxy) -2-
Hydroxypropyl) isocyanurate, tris (3-
(2 ', 3'-dihydroxypropyithio) -2-hydroxypropyl) isocyanurate and the like. Furthermore, tris (2,3-dihydroxypropyl)
It is also possible to use an isocyanurate in which a part of the hydroxyl groups is etherified or esterified with an alcohol or fatty acid having a long-chain alkyl group. Among them, tris (2,3-dihydroxypropyl) isocyanurate represented by the following formula (Formula 8) is preferable because it has good solubility in water and good handleability and adhesiveness.

[0018]

Embedded image

In the present invention, the compound (A) may be used in combination with other components such as a leveling agent. The smoothing agent here is a conventionally known smoothing agent for fibers, for example, hydrocarbons such as mineral oil, butyl stearate, oleyl laurate, isostearyl palmitate, esters of higher alcohols and higher fatty acids such as oleyl oleate,
Esters of higher alcohols and dibasic acids such as dioctyl sebacate, dioctyl azelate and dioleyl adipate, esters of dihydric alcohols and higher fatty acids such as neopentyl glycol dilaurate, diethylene glycol dilaurate and diethylene glycol dioleate, glycerin trioleate, tri Esters of trihydric alcohols such as methylolpropane decanate and higher fatty acids, tetrahydric or higher alcohols such as pentaerythritol tetraoleate and higher fatty acid esters, higher alcohols such as dioleyl phthalate, trioctyl trimellitate and tetraoctyl pyromellitate. And an ester of an aromatic carboxylic acid.

Further, an antistatic agent, an adhesion improver such as an amine compound, an antioxidant, an acid anhydride and the like may be used in combination in order to additionally impart the performance which is insufficient with only the leveling agent. Examples of amine compounds include aliphatic amines such as hexamethylenediamine, diethylenetriamine, and hexylamine; alicyclic amines such as piperazine; aromatic amines such as p-aminoaniline and p-aminophenol; and heteroamines such as pyrrole and imidazole. Examples include cyclic amines.

The content of the compound (A) contained in the treating agent is 0.1% by weight or more, preferably 40 to 80% by weight, more preferably 50 to 70% based on the active ingredient of the treating agent.
% By weight.

The method of applying the above-described treatment agent to the polyester fiber is not particularly limited. For example,
As a 1 to 25% by weight aqueous emulsion liquid, by any method such as a roller method, a dipping method, or a spray method, spinning of directly drawn yarn, after-oil, spinning of separately-drawn yarn, drawing, after-oil, or yarn treatment or It can be given at any stage such as code processing.

The adhesion amount of the treating agent to the fiber weight is 0.2
It is preferably in the range of 20 to 20% by weight, and when applied in the yarn making stage, 0.3 to 1.0% by weight, particularly 0.4 to 0.6% by weight is preferable. On the other hand, when it is applied by post-processing such as yarn processing or cord processing, it is preferably 0.5 to 5.0% by weight, particularly 1.0 to 4.0% by weight.

The polyester fiber of the present invention thus obtained usually has a total fineness of 500 to 1500 denier and a total number of filaments of 100 to 1000, but in some cases, 2
000 to 6000 denier is mixed. To use the polyester fiber of the present invention for adhesion to rubber, first, in a twisting step, twist of 10 to 100 times / m is applied.

Next, this cord is treated with an RFL treating agent. This treating agent is a composition containing resorcin / formalin / rubber latex. The resorcin / formalin / rubber latex used here is usually called RFL, and the molar ratio of resorcin / formaldehyde is 1 :. 0.1 to 1: 8, preferably 1: 0.5 to
It is used in the range of 1: 5, particularly preferably 1: 1 to 1: 4.

Examples of the rubber latex include natural rubber latex, styrene / butadiene / copolymer latex, vinylpyridine / styrene / butadiene terpolymer latex, nitrile rubber latex and chloroprene rubber latex, and these are used alone or in combination. . Among these, vinyl pyridine, styrene,
When the butadiene terpolymer latex is used alone or in combination, excellent performance is exhibited when it is used in an amount of ½ or more of the total latex weight.

The mixing ratio of resorcin-formalin and rubber latex depends on the adding ratio of the additive (F) described later, but the solid content ratio is 1: 1 to 1:15, preferably 1 :.
It is preferably in the range of 3 to 1:12. If the ratio of the rubber latex is too low, the treated polyester fiber material becomes hard and the fatigue resistance becomes poor. On the other hand, if the amount is too large, satisfactory adhesive strength and rubber adhesion cannot be obtained.

An additive (F) such as a blocked polyisocyanate compound may be added to RFL. The blocked polyisocyanate is obtained by reacting an aliphatic, alicyclic or aromatic polyisocyanate with oxime, phenol, caprolactam or the like. These additives are usually used in an aqueous dispersion using an emulsifier.

The addition ratio of the blocked polyisocyanate compound or the like is 0.5 to 30% by weight, preferably 1.0 to 20% by weight, based on the RFL. If the amount added is too small, good adhesion and rubber adhesion cannot be obtained. on the other hand,
If the amount added is too large, the viscosity of the treating agent will remarkably increase, making it difficult to treat the fiber material. In addition, the adhesive strength and the rubber adhesion rate have reached the saturation value and the effect of increasing the addition amount does not increase, the cost only rises, the fiber material after treatment becomes significantly hard and the strength decreases. The drawback is that it will come. The above RFL usually has a total solid content of 10 to 10.
It is adjusted to contain 25% by weight.

To adhere the above RFL to the polyester fiber material obtained by the present invention, application by a roller,
Any method such as spraying from a nozzle or dipping can be adopted. The amount of solid matter attached to the fiber is 0.5 to 15
It is preferable to make it adhere by weight%, more preferably 1 to 10% by weight. In order to control the amount of the solid content attached to the fibers, means such as squeezing with a pressure contact roller, scraping with a scraper, blowing with air, suction, and beating with a beater may be used.

In the present invention, after treatment with a treating agent containing RFL, it is dried at 80 to 180 ° C. for 0.5 to 5 minutes, more preferably 1 to 3 minutes, and then 150 to 260 ° C., further preferably 220 to Heat treatment is performed at a temperature of 250 ° C. for 0.5 to 5.0 minutes, more preferably 1 to 3 minutes. If the heat treatment temperature is too low, the adhesion with rubbers becomes insufficient, while if the temperature is too high, the polyester fibers are melted and fused, become extremely hard, or strongly deteriorate, and cannot be put to practical use.

[0032]

The compound (A) contained in the treating agent of the present invention has an isocyanuric acid skeleton and therefore has excellent affinity with polyester fibers and, at the same time, 2,3-
Since it has a dihydroxypropyl group, it is an adhesive (RF
It also has an excellent affinity with L). As a result, it is presumed that the adhesiveness between the polyester fiber and the rubber becomes extremely good. Therefore, the polyester fiber of the present invention can be suitably used to reinforce rubber composites such as tires, belts and hoses in the same manner as polyester fibers treated with conventional epoxy compounds and the like.

[0033]

The present invention will be described in more detail with reference to the following examples. All% in the examples represent% by weight. Also,
The cord peeling adhesive strength and the pulling adhesive strength in the examples are values obtained as follows. <Cord peeling adhesive strength> It shows the adhesive strength between the treated cord and rubber. Un-vulcanized rubber sheet with natural rubber as the main ingredient
It was vulcanized at a pressing pressure of 50 kg / cm ² at 0 ° C. for 30 minutes, and then 5 cords were peeled in a direction of 90 degrees from the rubber sheet surface at a speed of 200 mm / min while leaving the cords at both ends. The force required is shown in kg / 5. <Cord pull-out adhesive strength> This shows the shear adhesive strength between the treated cord and rubber. Embed the cord in an unvulcanized rubber block containing carcass containing natural rubber as a main component,
Vulcanization was performed at 30 ° C. for 30 minutes, and then the cord was pulled out of the rubber block at a speed of 200 mm / min, and the force required for pulling out was expressed in kg / cm.

[Example 1, Comparative Examples 1 and 2] Polyethylene terephthalate having an intrinsic viscosity [η] of 0.89 was melt-spun according to a conventional method, and tris (2,3) was used as the compound (A) in the final step of stretching. -Dihydroxypropyl)
A 10% aqueous emulsion solution containing isocyanurate was applied by a roller method and then dried at 130 ° C. to obtain 1500 denier / 250 filament polyethylene terephthalate fiber. The amount of the treatment agent attached is 0.
5%. 40 x 4 of this multifilament
A cord of 3000 denier / 500 filament was obtained by twisting at 0T / 10 cm.

A 10% aqueous solution of caustic soda 12.3
g, 28% aqueous ammonia solution 34.0 g was added to water 318.0.
In addition to g, 72.0 g of Resorcin-formalin initial condensate Adhar RF (Hodogaya Chemical Co., Ltd., 43% acetone solution) reacted with an acidic catalyst was added to the resulting aqueous solution with sufficient stirring. Stir to disperse. Then, Nipol 2518FS (Nippon Zeon Co., Ltd., vinyl pyridine / styrene / butadiene terpolymer water emulsion) 268.5 g and Nippol LX-112 (Nippon Zeon Co., Ltd., styrene / butadiene copolymer 41% water emulsion) 115. Dilute 0 g with 148.0 g of water. The resorcinol / formalin initial condensation dispersion was slowly added to this diluted solution, and 31.2 g of formalin (37% aqueous solution) was further added and uniformly mixed, and the resulting blended solution was subjected to RFL treatment. Agent (20%
Concentration).

The obtained cord was used as a computer treating machine (CA Ritzler Co., Ltd., tire cord treating machine).
After being dipped in the RFL treating agent using the above, it is dried at 170 ° C. for 2 minutes and then heat-treated at 230 ° C. for 1 minute. The solid content of the RFL treating agent was adhered to the treated polyester tire cord by 5.0% by weight. The treated cord thus obtained was embedded in an unvulcanized rubber containing carcass containing natural rubber as a main component and vulcanized at 150 ° C. for 30 minutes at a pressing pressure of 50 kg / cm ² .

As a comparative example, the compound (A) was not used, and the compound (A) was replaced with Denacol EX-3.
With respect to the one using 14 (manufactured by Nagase Kasei Co., Ltd., glycerol polyglycidyl ether), a treated cord was prepared in the same manner as in Example 1 except for the above, and the adhesion was evaluated. The results are shown in Table 1. As is clear from Table 1, the adhesion level of the one used in the present invention shows a value equal to or higher than that of the one using the epoxy compound.

[Examples 2 to 3] In Example 1, the amount of the compound (A) contained in the treating agent was changed as shown in Table 1, and the other conditions were the same as in Example 1. The results are also shown in Table 1.

[0039]

[Table 1]

[Examples 4 to 5] The procedure of Example 1 was repeated except that the coating amount of the treating agent was changed as shown in Table 2. Table 2 shows the results.

[0041]

[Table 2]

Claims (3)

[Claims] 1. A polyester fiber having an isocyanuric acid skeleton and at least one 2,3-dihydroxypropyl group in its molecular structure, represented by the following general formula (Formula 1).
A polyester fiber having excellent adhesiveness, characterized in that a treating agent containing a compound (A) represented by Embedded image 2. The polyester fiber having excellent adhesiveness according to claim 1, wherein the compound (A) is tris (2,3-dihydroxypropyl) isocyanurate represented by the following formula (Formula 2). Embedded image 3. The polyester fiber having excellent adhesiveness according to claim 1, wherein the amount of the treatment agent attached is 0.2 to 20% by weight based on the weight of the fiber.