JPH02278090A - Hose for ehtyleneglycol - Google Patents

Abstract

PURPOSE:To employ polyester base composite fibers as a reinforcing material by a method wherein the reinforcing material is a core and sheath type composite fiber and formed such that limiting viscosity of a core component exceeds a specified value, polyester has terminal calboxyl group concentration being below a specified value, a sheath component is polyamide, and the sheath component occupies a specified wt% of a whole. CONSTITUTION:In a hose for ethyleneglycol, a polyester series composite fiber is a core and sheath type composite fiber formed such that a core component is polyester having limiting viscosity of 0.7 or more, terminal carboxyl group concentration of 12g equivalent/10<6> g or less, a sheath component is formed of polyamide, the sheath component occupies 10 - 30wt% of a whole, and strength is at least 7.0g/d, and the polyester series composite fiber is used as a reinforcing material. This constitution provides a hose for ehtyleneglycol in which a polyester fiber durability to ehtyleneglycol of which is improved without damaging characteristics, e.g., high strength, a high elastic modulus, low shrinkage, being the features of a polyester fiber is used as a reinforcing material.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a hose reinforced with polyester fibers, and more specifically to a hose reinforced with polyester fibers that have good durability against ethylene glycol solvents. This relates to ethylene glycol hoses, such as brake hoses.

[Conventional technology]

Conventionally, polyester, nylon 6, nylon 6.6, rayon, vinylon, etc. have been used as rubber reinforcing materials.

In particular, polyester fibers such as polyethylene terephthalate are suitable as rubber reinforcing materials because they have physical properties such as high strength, high Young's modulus, and low elongation creep, and are also excellent in fatigue resistance.

In particular, the hose reinforcing material is not only highly strong, but also has little dimensional change due to heat during vulcanization, and the elongation of the reinforcing cord allows for sharp cutting when cutting into regular hoses. It is required to have a small amount and high rigidity.

- Polyester fiber is widely used as an extremely suitable material for meeting these required properties, as it has high strength, high modulus of elasticity, and low thermal shrinkage.

However, polyester fibers also have the fundamental drawback of extremely poor durability against ethylene glycol, and for this reason, although they are used as various rubber reinforcing materials, they are used in brake hoses and other products that contain ethylene glycol-based solvents. It has been considered unusable as a reinforcing material.

Furthermore, in recent years, due to the problem of ozone depletion, there has been a movement to replace existing fluorocarbons with new fluorocarbons, and there is a strong possibility that polyethylene glycol-based solvents will be adopted as new fluorocarbons. This predicts that polyester fiber, which is already commonly used as a reinforcement material for cooler hoses, will no longer be able to be used in this field in the near future unless its durability against ethylene glycol is improved. It is something that makes you

[Problems to be Solved by the Invention] The present invention has been made against the background of the problems of the prior art described above. An object of the present invention is to provide an ethylene glycol hose using polyester fiber as a reinforcing material and having improved durability against water.

[Means to solve the problem]

The present invention is a core/sheath type composite fiber, in which the core component is polyester having an intrinsic viscosity of 0.7 or more and the terminal carboxyl group concentration is 12 g equivalent/106 g or less, the sheath component is polyamide, and the sheath component is 10 This is an ethylene glycol hose whose reinforcing material is a polyester composite fiber that accounts for ~30% by weight and has a strength of at least 7.0 g/d.

In the present invention, polyester refers to polyethylene terephthalate whose main repeating unit is ethylene terephthalate.
Although the target is phthalate, it may also be a copolyester in which a third component is copolymerized within a range (for example, 15 mol % or less) that does not essentially change the properties of the phthalate. In particular, as the third component, the following formula (where A is an aromatic group or an aliphatic group,
, is an ester-forming functional group, Xt is the same or different ester-forming functional group or hydrogen atom, R,, R
, R, and R4 are the same or different groups selected from alkyl groups and aryl groups, and n is a positive integer] A copolyester obtained by copolymerizing 0.05 to 20 mol% of a sulfonic acid phosphonium salt. is more desirable because it has excellent compatibility with polyamide.

The polyester used as the core component has an intrinsic viscosity of 0.7
The above is necessary. If the intrinsic viscosity is less than 0.7, not only will it not be possible to obtain a high-strength yarn required for rubber reinforcement, but the resistance to strength deterioration when eroded by ethylene glycol will also be significantly reduced. . That is,
The higher the initial intrinsic viscosity, the higher the resistance to strong deterioration.

In this respect, the higher the intrinsic viscosity, the better;
If it is too high, the viscosity during melting will increase and it will be difficult to spin yarn, so it is usually better to set it to 1°0 or less.

The terminal carboxyl concentration of the polyester core component is 12
It is necessary to set it to 1f/10'g or less per g, and it is particularly preferable to set it to 8g equivalent/1O1'g or less. If the terminal carboxyl concentration exceeds 12 g equivalent/10'g, the rate of erosion and deterioration due to ethylene glycol increases, and even if polyamide is used as a protective layer of the sheath, the desired strength cannot be maintained.

On the other hand, the polyamide forming the sheath portion is a fiber-forming polyamide obtained from a polymerizable diamine, a dicarboxylic acid, a monoaminocarboxylic acid, or an amide-forming derivative thereof. Furthermore, copolymers of two or more of these can also be used. A suitable polyamide is polyε-cabramide (
Nylon 6), polyhexamethylene adipamide (nylon 6.6), polyhexamethylene sebacamide (nylon 6.10), but other aliphatic polyamides,
Polyamides containing aromatic, alicyclic or heterocyclic rings in the main chain can also be used.

These polyamides may also contain small amounts of additives, such as UV absorbers, heat stabilizers, matting agents, dyes, pigments, etc.

The degree of polymerization of polyamide should be selected appropriately depending on the type and use of polyamide, but in general, in the case of polyε-cabramide (nylon 6), the intrinsic viscosity [η] measured in a metacresol solution at 35°C is 0. .8 or more are preferable, and i, o to 1.5 are particularly preferable.

In the present invention, a core-sheath type conjugate fiber is obtained by using the polyester as a core component and the polyamide as a sheath component. The purpose of the polyester composite fiber of the present invention is not to have crimp ability, but to protect the outer layer of polyester with a polyamide layer that has relatively good durability against ethylene glycol. It is desirable to use concentric conjugate fibers, and the sheath component must not be eccentric, at least locally, so that the polyester itself is not exposed to the surface.

The proportion of polyamide in the sheath component is such that it does not impair the characteristics of high strength and high elastic modulus of the polyester core component, and forms a protective layer of polyamide against ethylene glycol on the polyester surface layer. 10~
It is necessary to set the content to 30% by weight. The proportion of sheath components is
If it is less than 10%, it is difficult to form a complete polyamide coating layer on the polyester surface layer, and during spinning or stretching,
Alternatively, the core component may be exposed from the sheath component during cord formation, making it impossible to form a sufficient polyamide protective film against ethylene glycol. On the other hand, if the proportion of the sheath component exceeds 30% by weight, the characteristics of polyamide will reduce the characteristics of polyester, making it impossible to maintain a high elastic modulus, which is inappropriate.

As mentioned above, the polyamide sheath component is 10 to 30% by weight.
In order to maintain the high strength and high elastic modulus characteristic of polyester in a polyester-rich polyester composite fiber with a polyester core component of 90 to 70% by weight, it is necessary to It is necessary to evenly stretch the components.

Generally, polyamide has poorer stretchability than polyester, so it is desirable to adjust the stretchability of polyester to a level commensurate with that of polyamide.

If we try to adjust the stretchability by controlling the molecular weight, for example, in terms of the limiting viscosity [η], we can use nylon 6 as a polyamide.
When using a polyester having [η] of 1.3, polyethylene terephthalate having [η] of around 0.9 is suitable for achieving high strength and high Young's modulus.

A preferable combination of [η] is polyester of 0.7 to 1
．． 0 and polyamide can be appropriately selected in the range of 0.8 to 1.5 depending on the purpose.

Further, the cutting strength of this polyester composite fiber needs to be at least 7 g/d.

If the strength is less than 7 g/d, not only will it not be possible to achieve the cord strength required for a rubber reinforcing material, but the density of the amorphous portion will be low, making it susceptible to erosion and deterioration due to ethylene glycol.

The ethylene glycol hose using the polyester composite fiber of the present invention as a reinforcing material is manufactured, for example, by the following method.

First, the core component polyester is polymerized by melt polymerization to an intrinsic viscosity [η] of about 0.6 to 0.7, and then further increased to an intrinsic viscosity [η] of about 0.6-0.7.
] A known method, solid phase polymerization, is used.

For example, a desired intrinsic viscosity of 0.7 to 1 can be obtained by carrying out a polymerization reaction for several hours at a solid state polymerization temperature of 220 to 230°C under reduced pressure while stirring a melt polymerized chip cut to about 4 x 4 x 2 mm in a rotary dryer. °0 is achieved.

If the terminal carboxyl concentration of the polyester polymer is 19 to 20 g equivalent/1.0''g at the completed stage of melt polymerization, the terminal carboxyl concentration of the polyester polymer can be reduced to 11 to 14 g equivalent/10 hg by solid phase polymerization. This solid-phase polymerized polyester polymer (chip) is reacted with a terminal carboxyl group blocking agent to further lower the terminal carboxyl concentration, and then melt-spun and stretched to obtain a terminal carboxyl concentration of 12.
The polyester fiber can have a g equivalent/106 g or less, particularly 8 g/m/106 or less. The reaction between the polyester fiber and the terminal carboxyl group blocking agent is usually carried out in a molten state, and after the terminal carboxyl group blocking agent is quantitatively deposited on the polyester polymer, the polyester polymer is melted or the polyester in the molten state is reacted with the terminal carboxyl group blocking agent. A method such as quantitatively pressurizing the terminal carboxyl group blocking agent into the polymer may be used as appropriate.

As the terminal carboxyl group blocking agent, any substance can be used as long as it is thermally stable and can react with the carboxyl group of the polyester when melted. For example, terminal carboxyl group blocking agents such as oxazoline type and epoxy type are preferred. It can be used for.

The thus obtained polyester polymer with an intrinsic viscosity [η] of 0.7 or more and a terminal carboxyl concentration of 12 g equivalent/10 hg or less is melted at 260 to 330°C to obtain a polyamide with an intrinsic viscosity of 0.8 or more, which becomes an impulse component. It is melted, supplied and discharged to a conventionally known concentric core-sheath type nozzle, cooled with cooling air, coated with oil, rolled up as an unstretched package through a take-up roller, and subjected to stretching heat treatment in a separate process, or taken off. After passing through the rollers, the film may be continuously subjected to stretching heat treatment without being wound up.

The stretching heat treatment conditions include preheating at a temperature higher than the glass transition temperature of the polyester, for example 80 to 95°C, followed by a stretching ratio depending on the speed of the take-up roller, for example 50 to 60.
It may be stretched twice in two steps and heat treated at a temperature higher than the crystallization temperature of polyester, for example, 180 to 250°C.

In order to make the polyester composite fiber of the present invention particularly suitable as a rubber reinforcing material, by optimizing the spinning conditions and stretching heat treatment conditions, the strength is 7 g/d or more, 150°
The dry heat shrinkage rate of C (left in a relaxed state at 150''C for 15 minutes, taken out and measured for shrinkage rate, according to the method specified in JIS L-1073) is 4% or less.

The polyester composite fiber thus obtained is formed into a hose by, for example, the following method. That is,
Three multifilaments with a total denier of 1,000 denier are spun together to give a single twist of 35T/l0C11, and then heated with steam at 120°C for about 2 minutes to set the twist, and then coiled on a mandrel. It can be wrapped around and vulcanized to form a hose, or a mixture of a dispersion of a resorcinol-formaldehyde precondensate and a styrene-butadiene copolymer latex can be used as an adhesive (usually
120°C" after immersed in adhesive called RFC"?
After drying for 1 minute and heat-treating at 200°C for about 2 minutes, it is wound into a coil around a mandrel as described above and used as a rubber reinforcing material to form a hose.

The thus obtained ethylene glycol hose using the polyester composite fiber of the present invention as a reinforcing material has little deterioration of the reinforcing material in ethylene glycol, and conventional polyester fibers could not be put to practical use due to a significant decrease in strength. Can be used as an ethylene glycol hose.

In the hose of the present invention, the polyester composite fiber used as a reinforcing material is polyester-rich and maintains properties of high strength, high elastic modulus, and low shrinkage that are suitable for hoses. It has good properties and sufficient pressure resistance and dimensional stability, so it can be used in a wide range of hoses that require durability against ethylene glycol, such as brake hoses and cooler hoses.

In addition, the intrinsic viscosity of the polyester in the present invention is 35
It was measured using an 0-chlorophenol solution at ゛C.

Furthermore, the terminal carboxyl group concentration can be determined by dissolving a polyester sample in benzyl alcohol and dispersing it in chloroform, and using a phenol red indicator to determine the concentration of the terminal carboxyl group. IN Na
Titrate with OH-benzyl alcohol to change -COOH in the polyester to COONa, and reduce the required 0, IN of N.
a The amount of -COOH was determined from the amount of OH.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

In Examples and Comparative Examples, strength and elongation, strength at 2% elongation, ethylene glycol durability, and cross-sectional condition were evaluated as follows.

Kinado■ Using Shimadzu Autograph, sample length 25c+a
, the S-3 curve was measured under the conditions of an elongation speed of 120%/min, a recording speed of 60 cm/min, and an air chuck, and the strength (g/d)
, the strength (g/d) at 2% elongation was determined.

120 was used for accelerated evaluation under more severe conditions than ethylene dicol rubber.
A fiber sample was immersed for 48 hours in an ethylene glycol bath heated and maintained at C. The strength before and after immersion was measured, and the strength retention rate was calculated from the following formula, which was used as a measure of durability.

Strength retention rate - (strength after immersion) / (strength before immersion) X1
00 (%) A microscopic photograph of a cross section of the 1° fiber was taken and the condition was visually observed.

Examples 1 to 5 Intrinsic viscosity is 0.60, terminal carboxyl group concentration is 19g
/10bg polyethylene terephthalate chips (4X
4 x 2 m) was placed in a vacuum rotary dryer with a capacity of IM, nitrogen gas was supplied at 102/min as a carrier under a vacuum of 1 msiHg, and the mixture was heated to 230°C to perform a solid phase polymerization reaction.

The reaction time of the solid phase polymerization was varied depending on the intrinsic viscosity (Table 1) of the polyester fiber to be obtained.

The terminal capping agent shown in Table 1 was added in the amount shown in Table 1 to the obtained solid phase polymerized chip, and 31
A melt reaction is performed at 0°C, and the intrinsic viscosity is 1.
Nylon 6 from No. 3 was melted at 275°C, and a gear pump was applied to the spinning bag having a core-sheath type spinneret (hole diameter: 0.3g, number of holes: 48) maintained at a temperature of 295°C at the ratio shown in Table 1. It was supplied while being measured. A linear velocity of 0 at which the yarn discharged from the spinneret is blown across the yarn within the spinning tube.
．． Cooling was performed by cooling air at a rate of 2 m/sec.

Spinning oil (aqueous 10% emulsion) is applied to this discharged yarn.
was attached at a fiber weight ratio of 3%, and then wound up at 400 m/min.

Next, this undrawn yarn was preheated with a heating roll at 90°C, then stretched in the first stage to 4.5 times, followed by heat treatment for 0.6 seconds with a heating roll at 180°C, and wound up at a speed of 330 m/min. . The results are shown in Table 1.

Comparative Example 1 A melt-polymerized chip of 110" without solid-phase polymerization
The procedure was carried out in the same manner as in Example 1, except that the sample was pre-dried at C for 2 hours and then dried at 160°C for 5 hours to melt. The results are shown in Table 1.

Comparative Example 2 The same procedure as Example 1 was carried out except that the first stage stretching ratio was 3.5 times. The results are shown in Table 1.

Comparative Example 3 The same procedure as Example 1 was carried out except that solid phase polymerization was carried out without using an end capping agent. The results are shown in Table 1.

Comparative Examples 4-5 The same procedure as in Example 1 was carried out except that the core/sheath ratio was changed. The results are shown in Table 1.

Comparative Example 6 The same procedure as Example 1 was carried out except that the sheath component was not supplied. The results are shown in Table 1.

〔Effect of the invention〕

The ethylene glycol hose using polyester composite fiber as a reinforcing material of the present invention has the same good properties as general-purpose hoses using polyester fiber as a reinforcing material, such as high pressure resistance, high dimensional stability, and workability. It has extremely high durability against ethylene glycol, which conventional polyester fibers could not achieve, and its industrial value is great.

Patent applicant: Teijin Ltd. Agent: Patent Attorney Takashi Shirai

Claims (1)

[Claims] (1) Core-sheath type composite fiber, where the core component has an intrinsic viscosity of 0
．． 7 or more, terminal carboxyl group concentration is 12g equivalent/10
^6g or less of polyester, a sheath component made of polyamide, the sheath component accounting for 10 to 30% by weight of the whole, and a hose for ethylene glycol whose reinforcing material is polyester composite fiber having a strength of at least 7.0 g/d. .