JPH0648073B2 - Polyester fiber reinforced water supply hose - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water supply hose using a polyester fiber as a reinforcing material.

(Prior Art) Conventionally, inexpensive rayon has been used as a reinforcing material for a water supply hose made of rubber, polyvinyl chloride, or the like.

(Problems to be solved by the invention) As described above, a water supply hose using rayon as a reinforcing material has poor durability, and its service life becomes extremely short particularly when used in a hot and humid area of Southeast Asia. There was a problem.

The object of the present invention is to solve the above conventional problems, durability,
In particular, it is to provide a water supply hose which has excellent wet heat durability and is inexpensive.

(Means for Solving Problems) The present invention is a drawn yarn obtained by using a crystalline undrawn yarn as a starting raw yarn, which is made of polyester having ethylene terephthalate as a main repeating unit and an intrinsic viscosity of 0.9 or more. The polyester fiber reinforced water supply hose is characterized in that a polyester fiber having an initial modulus of 90 g / de or more and a moisture and heat resistance coefficient of 0.6 or more is used as a reinforcing material.

The polymer constituting the polyester fiber used in the present invention has an ethylene terephthalate repeating unit in the molecular chain.
A polyester containing 90 mol% or more, preferably 95 mol% or more. Polyethylene terephthalate is preferable as such a polyester, but it is acceptable to include other copolymerization components in a proportion of less than 10 mol%, preferably less than 5 mol%. Examples of such a copolymerization component include isophthalic acid, naphthalenedicarboxylic acid, adipic acid, oxybenzoic acid, diethylene glycol, propylene glycol, trimellitic acid, and bentaerythritol. Further, these polyesters may contain additives such as stabilizers and colorants.

The polyester fiber used in the present invention needs to have an intrinsic viscosity of 0.90 or more determined from a 25 ° C. O-chlorophenol solution. If the intrinsic viscosity is less than 0.90, high-strength polyester fiber cannot be obtained and sufficient hose strength cannot be maintained. The intrinsic viscosity is preferably 0.9 to 1.3.

The polyester fiber used in the present invention must have an initial modulus of 90 g / de or more. If the initial modulus is less than 90 g / de, the hose will have poor dimensional stability.

Furthermore, the polyester fiber used in the present invention is required to have a moisture heat resistance coefficient of 0.6 or more. Moisture and heat resistance coefficient
If it is less than 0.6, the hose will have poor durability. Here, the moist heat resistance coefficient is S ₁ / S ₀ when the polyester fiber is heat-treated at 140 ° C. for 24 hours and the strength before the heat treatment is S ₀ and the strength after the heat treatment is S _1.
Is represented by. The moisture heat resistance coefficient of rayon, which has been conventionally used as a reinforcing material for water supply hoses, is as low as around 0.5.

The polyester fiber used in the present invention is obtained, for example, by the following method.

Polyester with ethylene terephthalate as the main repeating unit and an intrinsic viscosity of 0.95 to 1.5 or an intrinsic viscosity of 0.7 to 0.9
Polymerization accelerator is reacted with polyester of No. 1 and melt-transported by an ordinary method, and then discharged from the spinneret to a yarn with a fineness of 1 to 20 de after stretching and a total denier of 500 to 2000 de, and immediately cooled immediately after discharging. The temperature is kept below the melting point up to the crystallization start temperature, or exposed to a heating atmosphere having a temperature above the melting point for a certain period of time to perform delayed cooling. After that, the yarn is cooled and solidified. At this time, it is useful to cool and solidify under the following conditions.

[X is the distance from the spinneret surface to the cooling air (room temperature) blowing surface of 450 mm or less, and y is the blowing length of the cooling air of 100 to 500 m.
m and Q are the amount of cooling air blown out from 2 to 6 Nm ³ / min] Then, after cooling and solidifying as described above, after applying the oil agent, 20
Collect at a speed of 00m / min or more. The oil agent can be applied by any method such as an oiling roller method or a spray method. As the oil agent, any fiber oil agent can be applied as necessary. At this time, it is useful to add a surface treatment agent in order to impart adhesiveness to rubber, polyvinyl chloride and the like.

By selecting the above conditions from time to time, the intrinsic viscosity will be 0.
A crystalline unstretched fiber having a breaking elongation of 90% or more and a breaking elongation of 150% or less, the crystallinity Xx and the birefringence Δn are Xx = 2.4 × 10 ² × Δn + 4 [where Xx is X-ray wide angle diffraction And the crystallinity of Δn is 0.06 or more in birefringence], and an unstretched fiber having a birefringence of 0.06 or more can be obtained.

Such unstretched fibers also have a draft ratio of the discharged fibers from the spinneret to after discharge of 300 to 7,000, an orifice diameter of the spinneret of 0.55 to 2.5 mm, and a take-up speed of 2000 to 6000 m / min. Can also be obtained. Here, the draft rate is the ratio of the fiber take-up speed to the polymer discharge linear velocity (orifice outlet velocity).

In the present invention, the unstretched fiber having the above characteristics, which has been drawn at the above speed, may be continuously stretched (directly stretched) after spinning, or may be wound once and then stretched in a separate step. (Separate postponement). In particular, the stretching method by the separate stretching is preferable from the viewpoint of reducing stretching strain and heat treatment strain during stretching. That is, the unstretched fiber is Tg + 15 to Tg + 50 ° C.
(Where Tg is the glass transition temperature of the fiber) and is at least 0.
After preheating for 5 seconds, the first stage is drawn at a draw ratio of 75% or less of the total draw ratio to obtain a birefringence of 1.2 to 3.3 times the birefringence of the undrawn fiber. Next, the single-stage drawn yarn is further heat-treated in multiple stages. At this time, the melting temperature of the fiber after multi-stage drawing was -50 ° C to the melting temperature-11
It is preferable to perform a tension heat treatment of 0 to 20% while maintaining the temperature in the range of 0 ° C for 0.4 to 1.5 seconds.

The polyester fiber obtained in this manner is placed in a resin hose or a rubber hose as it is or after being twisted and knitted and woven, and then as it is or after heat treatment according to a conventional method.

(Examples) Hereinafter, the present invention will be described with reference to Examples.

All parts in the examples are parts by weight.

Example 97 parts dimethyl terephthalate, 69 ethylene glycol
Parts, 0.034 parts of calcium acetate monohydrate and 0.025 parts of antimony trioxide were charged into an autoclave, and methanol produced as a result of transesterification was removed at 180 to 230 ° C while gently passing nitrogen through, and then 50% of H ₃ PO ₄ was added. % 0.05% aqueous solution was added to increase the heating temperature to 280 ° C and gradually reduced pressure was applied, and the polymerization reaction was continued for about 1 hour and 50 minutes, and the intrinsic viscosity was 0.80 and the amount of unterminated carboxyl group was 28 equivalent / 10 ⁶ g polymer. Was obtained.

After 100 parts of this polymer chip was dry-blended with 2,2'-bis (2-oxazoline) (CE) in an amount shown in Table 1, it was melt-transported at about 300 ° C to obtain a pore diameter of 0.60 mm and a number of 250 pores. After being discharged from the spinneret, the discharge yarn was maintained under the cold conditions shown in Table 1, and then a cooling air of 25 ° C was applied over 300 mm for 4.0 mm.
After cooling and solidifying while spraying at Nm ³ / min, an oiling agent was applied by an oiling roller, and then wound at the take-up speed shown in Table 1. The properties of the unstretched fibers obtained are shown in Table 1.

This unstretched fiber was supplied to a roll heated to 85 ° C., and the unstretched fiber was stretched at a draw ratio (DR ₁ ) shown in Table 1 with a trading roll and then exposed through a gas bath heated to 325 ° C. The second stage drawing was performed at the indicated draw ratio (DR ₂ ). Then, using a heating roller at 130 ° C and a gas bath at 330 ° C, the magnification (DR ₃ ) shown in the table
It was heat treated for tension. The performance of the obtained drawn yarn is shown in Table 2.

Next, these drawn yarns were twisted at 5 T / 10 cm to form cords, subjected to RFL treatment, and then heat-treated at 245 ° C. for 2 minutes. An unvulcanized rubber hose was obtained by embedding a fiber reinforcing layer in which one piece of this treated cord was braided in a spiral shape in rubber. Then, the unblended rubber hose was vulcanized at 150 ° C. for 30 minutes to obtain a water supply hose having an inner diameter of 100 mm and an outer diameter of 105 mm.

The burst strength, dimensional stability and wet heat durability of this water supply hose were measured. The results are also shown in Table 2.

In addition, the burst strength, dimensional stability and wet heat durability of the water supply hose are 30 cm of the hose prepared as described above, pressure of 5 kg / cm ² ,
After being kept for 30 days while passing through a steam with a temperature of 150 ° C., the evaluation was carried out by the following method.

Bursting strength: judged by the presence or absence of cracks on the surface of the hose.

 3 or less: ○ 4 or more cracks: × Dimensional stability: The dimensional change of the hose before and after the treatment was measured.

 Dimensional change less than 3%: ◎, 3 to 5%: ○, more than 5%: × Wet heat durability: The hose was disassembled and the strength of the cord before and after the heat treatment was measured to obtain the strength retention rate.

Strength retention rate over 80%: ◎, 60-80%: ○, less than 60%: × As is clear from the above results, when the intrinsic viscosity of the reinforced polyester fiber used in the water supply hose is less than 0.90 (Experiment No. In 1), the burst strength of the hose is reduced, and when the initial modulus is less than 90 g / de (Experiment No. 3), the hose has poor dimensional stability. Further, when the moisture heat resistance coefficient of the polyester fiber is less than 0.6 (Experiment No. 5), the wet heat durability of the hose deteriorates. On the other hand, the water supply hose of the present invention (Experiment Nos. 2, 4, and 6) has excellent strength, dimensional stability, and wet heat durability.

(Effects of the Invention) According to the present invention, it is possible to provide a water supply hose having excellent strength, dimensional stability, and wet heat durability.

Moreover, since inexpensive polyester fiber is used as the reinforcing material, it is possible to provide a water supply hose having excellent cost performance.

Claims (1)

[Claims] 1. A polyester which has ethylene terephthalate as a main repeating unit and has an intrinsic viscosity of 0.9 or more, and has a crystallinity Xx and a birefringence Δn as Xx = 2.4 × 10 ² × Δn + 4 as a starting yarn. A drawn yarn obtained by drawing a crystalline undrawn yarn having a birefringence Δn of 0.06 or more and a breaking elongation of 150% or less, which has an initial modulus of 90 g / de or more and a moisture heat resistance. Coefficient is 0.
A polyester fiber reinforced water supply hose characterized by using a polyester fiber of 6 or more as a reinforcing material.