JPH0742616B2 - High strength polyester fiber - Google Patents

Description

TECHNICAL FIELD The present invention relates to high-strength polyester fibers. More specifically, the present invention relates to a high-strength polyester fiber for rubber reinforcement, which emits less smoke when treated with a resorcin / formalin / latex liquid (referred to as RFL liquid) after twisting and has a high strength in the obtained treated cord.

(Prior Art) In recent years, the need to improve tire quality and productivity has become more pronounced than ever, and there is a strong demand for higher strength and higher heat resistance of polyester fibers. Therefore, the polyester fiber is stretched at a higher temperature and a higher draw ratio for the purpose of obtaining high strength, so that a treatment agent having excellent oil film strength at high temperature and high contact pressure and excellent smoke emission is required. There is.

Further, the twisted yarn is treated with RFL liquid, dried and heat-treated to obtain a treated cord, which is required to have high strength and to emit less smoke during heat treatment.

In order to satisfy these requirements, conventionally, a leveling agent introduced with elemental sulfur, for example, a diester of thiodipropionic acid and a monohydric alcohol (JP-A-52-103590).
In addition, mono- and diesters of EO adducts of thiodipropionic acid and monohydric alcohols (JP-A-55-148216) have been proposed.

Further, particularly for the purpose of reducing the friction between fibers at the time of high contact pressure, a high molecular weight activator, for example, an alkylene oxide adduct of an ester of a polyhydric alcohol and hydroxymonocarboxylic acid, and maleic acid are essential components. Esters with carboxylic acid components (JP-A-59-223368) and the like have also been proposed.

However, in order to obtain filaments having a strength of more than 8.5 g / d, it is necessary to remarkably increase the yarn tension during spinning and drawing, and to raise the heating temperature remarkably, and the requirements for oil film strength and smoke emission are also required. It becomes more severe, and the predetermined effect cannot be obtained with the conventional combination of only the leveling agent and the high molecular weight active agent. That is, even if the strength of the filament is increased, the strength of the finally obtained treatment cord is not increased, and the smoking is also increased.

As means for solving such a problem, methods such as increasing the ratio of the leveling agent, using a polymer activator, or refueling a non-hydrating oil agent (JP-A-60-9919) have been proposed. However, all of them have a problem that they are inferior in re-emulsification property (solubility when the oil on the fiber enters the RFL liquid). If the re-emulsification property is lowered, the viscosity of the RFL solution is changed, or the emulsification balance of the RFL solution is disturbed and the latex portion is separated, which is not preferable. Then, in order to improve the re-emulsification property of such a treatment agent, it is considered that the ratio of the smoothing agent and the molecular weight are decreased, but these tend to increase smoke emission and decrease smoothness. It is not preferable because it exists.

(Object of the Invention) An object of the present invention is to provide a high-strength polyester fiber in which the treated cord strength is increased as the filament strength is increased even when the filament strength is 8.5 g / d or more, and the smoke emission is low. It is in.

(Structure of the Invention) As a result of intensive studies aimed at achieving the above object, the present inventors have found that a sulfur-containing ester-based leveling agent (hereinafter sometimes referred to as S-containing ester-based) having a specific molecular weight and an ether-based polymer activator. And a combination of nonionic activators,
The inventors have reached the present invention by knowing that a polyester fiber satisfying both smoke emission and RFL permeability can be stably obtained. That is, the present invention includes (a) 62% by weight or more of a leveling agent (component A) containing a sulfur-containing ester compound having a molecular weight of 600 or more as a main component, and (b) an ether type liquid having a molecular weight of 7000 or more and a liquid at 15 ° C. 8% by weight or more of polymer activator (component B), (c) 20% by weight or less of nonionic activator (component C) having a molecular weight of 800 or more and 270C or less, and A + B of 90% by weight or less A polyester fiber having a treating agent applied thereto, which is a high-strength polyester fiber characterized by simultaneously satisfying the following (i) to (iii).

(I) Filament strength ≧ 8.5 g / d (ii) Smoke generation ≦ 1500 (iii) RFL permeability ≦ 5 cm The present invention is a polyester fiber having a filament strength of 8.5 g / d or more in the final fiber after spinning. Target.
In the case of less than 8.5 g / d, even if the treatment agent used in the present invention is added, or even if the conventionally known treatment agent is added, the difference in the treatment code strength is almost expressed. do not do. However, it has been found that the strength of the treated cord obtained from the polyester fiber of the present invention increases at 8.5 g / d or more, particularly 9.0 g / d or more, as described later.

Smoothing agent (component A) constituting the treatment agent applied in the present invention
Needs to have a sulfur-containing ester-based smoothing agent with a molecular weight of 600 or more as the main component (here, the main component is the A component).
It means 50% by weight or more). When the molecular weight of the sulfur-containing ester is less than 600 or the ratio of the component A in the component A is less than 50% by weight, the smoothness of the treating agent is poor, yarn breakage occurs during drawing heat treatment, and the strength of the treated cord decreases. It is not preferable because the smoke generated during the production of the cord is large. Also,
The component A needs to be 62% by weight or more based on the treating agent. Even if it is less than 62% by weight, the smoothness of the treating agent is deteriorated, which is not preferable.

Here, the sulfur-containing ester-based leveling agent is a compound having a sulfur atom in the molecule, and examples thereof include diesters of thiodipropionic acid and higher alcohols. Examples of higher alcohols include saturated or unsaturated alcohols having a straight chain or side chain of natural or synthetic alcohols, and alcohols containing an aromatic nucleus, and among these, particularly preferred is a straight chain unsaturated aliphatic It is alcohol. Specifically, dioleyl thiodipropionate is preferably used.

As the ether-based polymer activator, ethylene oxide (EO), propylene oxide (P
Examples thereof include those obtained by polymerizing alkylene oxides such as O) and butylene oxide (BO) (homopolymers, copolymers), or those obtained by addition polymerization of polyhydric alcohols. The terminal group of such a compound may be a hydroxyl group, an alkoxy group or a phenoxy group. Also, the copolymerization ratio is not particularly limited as long as it shows a liquid state at 15 ° C. Preferable examples include polytetramethylene glycol or polyethylene glycol in which ethylene oxide and propylene oxide are randomly addition polymerized at both ends.

Such polyethers, which are often used for fiber processing, have a molecular weight of less than 7,000,
For use as a component, the molecular weight is 7,000 or more, and 15
It is necessary to show a liquid state at ° C, and it is necessary to use it in an amount of 8% by weight or more. When the molecular weight is less than 7,000, the smoothness of the treating agent is poor, and when it is solid, the smoothness of the treating agent becomes large, and at the same time, the adhesion with the rubber is reduced. It is not preferable because the property is poor and the re-emulsification property of the treatment agent is deteriorated.

In this treatment agent, the proportion of A + B used must be 90% by weight or less. If it exceeds 90% by weight, the re-emulsifying property of the treating agent is deteriorated, which is not preferable.

As the nonionic activator (C component), a polyhydric alcohol derivative having an emulsifying action and excellent in smoke emission and smoothness, such as castor oil, hydrogenated castor oil, trimethylolpropane, and glycerin, are mixed with ethylene oxide. Examples thereof include those added with 5 to 40 moles, and esters of these ethylene oxide-added polyhydric alcohols and aliphatic carboxylic acids. Specific examples thereof include polyoxyethylene hydrogenated castor oil ether and polyoxyethylene sorbitan trioleate. The molecular weight of the nonionic activator (component C) is 800 or more and 2700 or less, and the usage ratio thereof is required to be 20% by weight or less. If the molecular weight is less than 800, the fuming property of the treating agent is increased, while if the proportion used exceeds 20% by weight, the smoothness of the treating agent is impaired, which is not preferable.

In the treatment agent of the present invention, in addition to the components A, B and C, a small amount of an antistatic agent, an emulsification aid, an oxidation stabilizer, etc. may be added. For example, as an antistatic agent, oleyl phosphate and its salt (Na, K, amine, etc.), polyoxyethylene oleyl phosphate and its salt (Na, K, amine, etc.),
Examples include dioctyl sulfosuccinate Na salt, alkane sulfonate and salts thereof (Na, K, amine, etc.).

To impart such a treating agent to polyester fibers, conventionally known methods such as roller lubrication and nozzle lubrication can be used in the spinning step in the form of a non-hydrous type or an emulsion emulsified with water, but the filament strength is 8.5 g. Since high-speed spinning and high-temperature heat treatment are required to achieve a value of / d or more, it is preferable to use a non-water-containing treatment agent by a nozzle lubrication method.

The amount of the treatment agent attached is preferably 0.1 to 2.0% by weight, more preferably 0.2 to 1.0% by weight, based on the fibers.

The polyester fiber thus obtained has a temperature of 230 ° C. which will be described later.
It also has the effect of maintaining the smoke emission of 1500 or less and the RFL permeability of 5 cm or less as measured by. If the smoke emission exceeds 1500, the amount of smoke increases when the treatment code is formed by immersion treatment with RFL solution. Further, if the RFL permeability exceeds 5 cm, it is considered that the RFL liquid permeates into the inside of the treated cord and restricts the movement of each filament constituting the cord, but the strength of the treated cord tends to decrease.

The polyester fiber used in the present invention is obtained by directly spinning and drawing polyethylene terephthalate or a polyester mainly containing polyethylene terephthalate after melting in an extruder according to a conventional method.

(Function) It is not clear why the effect of the present invention appears when the filament strength is 8.5 g / d or more, but it is considered as follows at present under the present circumstances.

In order to increase the filament strength to 8.5 g / d or more, it is necessary to make the degree of crystallinity and orientation of the polyester fiber extremely high, the state of the fiber surface changes (friction between fibers changes), and the elongation Will also be lower. As a result, the tensile behavior of the cord is changed, and it is necessary to further improve the smoothness between fibers in order to increase the strength of the treated cord.

In order to achieve this requirement, the treating agent used in the present invention has the above-mentioned constitution and has a high heat resistance and a high surface strength of the treating agent (even if the contact pressure between filaments is high, the treating agent is high). Film is firmly attached to the filament surface). Therefore, it withstands the stringent spinning conditions (high temperature heat treatment, high spinning tension, high drawing tension) adopted to obtain polyester fibers with a filament strength of 8.5 g / d or more, and sufficient treatment agent remains on the filament surface, It reduces friction between filaments and improves drawability.

Even when the polyester fiber obtained in the present invention is twisted to form a cord, the surface strength of the treating agent is high, so that the treating agent remains sufficiently between the filaments even if a large pressure is applied between the filaments during the twisting. . Therefore, because of the compatibility relationship between the RFL solution and the treatment agent of the present invention, the permeability of RFL is 5
Since it becomes less than cm, the RFL liquid does not penetrate much into the inside of the treated cord, and the movement of each filament constituting the cord becomes free. As a result, the processing code becomes more powerful.

Further, since the treating agent used in the present invention has a large molecular weight and high heat resistance, it withstands a high temperature heat treatment at the time of producing a treated cord and also has a low smoke generation property.

Since the above effects are simultaneously exhibited, it is considered that the intended purpose can be achieved only when the treatment agent of the present invention is used.

(Effect of the invention) Since the polyester fiber of the present invention has a low smoke generation property, the working environment when used as a treatment cord is improved. Further, since the RFL permeability is low, a treatment code having a large strength can be obtained, and its industrial effect is extremely large.

(Examples) Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The evaluation method was as follows.

Sample: When polyethylene terephthalate having an intrinsic viscosity of about 0.95 is melted and produced by the direct spin-drawing method, the separately-described treatment agent is in the form of a non-hydrous type oil agent, and the deposition amount is 0.
5% by weight yarn (1500De / 250fil) was obtained.

Using a ring twisting machine for tire cords, twist 40x
40T / 10cm double twisted cord (raw cord) was created.

Then, this raw cord was immersed in an RFL solution using a single cord dipping machine, dried at 130 ° C. for 2 minutes, and then heat treated at 240 ° C. for 1 minute to obtain a treated cord.

Here, as the RFL solution, a PEXUL adhesive having the composition shown in Table 1 was aged according to a conventional method.

The amount of the RFL liquid deposited was 2.5% by weight.

Each property was measured according to the following methods.

Stretchability: 10kg bobbin surface (0.45m) spun at 5000m / min
Stretchability was defined as the number of fluffs with a length of 1 mm or more in ² ).

Smoke emission: on a vertically long (5 cm wide, 50 cm long) hot plate heater,
Apply a load of 250g to the threads so that they are almost in contact, and cover. Then, the amount of smoke in the air rising through the slit (width 5 cm, depth 1 cm) provided between the heater lower part and the cover is exhausted at a rate of 10 l / min through the small hole (diameter 5 mm) provided on the heater upper part. It was measured with a digital dust meter (Type P-3 manufactured by Shibata Chemical Instruments Co., Ltd.) and the cumulative value for 3 minutes was defined as the smoke density (times / minute). The heater temperature was 230 ° C.

Code strength: A tensile tester manufactured by Intesco was used to measure the strength of the treated cord with a test length of 25 cm, and the cord was treated as the treated cord.

Re-emulsification: Mix RFL solution and treatment agent (20% aqueous solution each) in a ratio of 6: 1, and put the solid content on a 20 cm x 20 cm square glass plate.
An amount of 0.4 mm was put in, air-dried in a draft at room temperature, and the dry state of the surface layer was visually observed for 2 days.

○: Uniform film is formed on the whole △: Partially hard film is formed (within 20% of the total surface area) ×… Partially hard film is formed (20% or more of the total surface area) RFL permeability: Tension of 200 g The 30 cm yarn to which the coating was applied was made vertical, and the lower end was immersed in the RFL liquid of a 20% aqueous solution, and after 5 minutes, the height of the RFL liquid rose from the liquid surface. It was conducted in an atmosphere of 20 ° C and RH65%.

Examples 1 to 8 and Comparative Examples 1 to 8 The spinning and drawing conditions were set so that the filament strength was 9.0 g / d, and the treating agents shown in Table 2 were used. The results are shown in Table 3.

As is clear from the results of Table 3, the present invention (Examples 1 to 1
According to 8), it is possible to obtain a high-strength polyester fiber having a high treated cord strength and a low smoke generation property.

However, the molecular weight of A component is less than 600, and the ratio of A component is 62.
If less than wt%, the molecular weight of component B is less than 7,000, the proportion of component B is less than 8% by weight, and A + B exceeds 90% by weight, the molecular weight of component C is less than 800, or the proportion of component C is 20% by weight.
When it exceeds, the stretchability, smoke generation property, cord strength, re-emulsification property and RFL penetration property are not satisfied and are insufficient.

Examples 9 and 10 and Comparative Examples 9 to 12 The spinning and drawing conditions were changed so that the filament strength was 8.0 g / d to 9.5 g / d, and the treating agent used in Example 1 or Comparative Example 1 was used. used. The results are shown in Table 4. In addition,
The results of Example 1 and Comparative Example 1 are also shown.

As is clear from this result, the present invention (Examples 1, 9 and 10)
According to, the treatment code has high strength, less smoke emission,
High-strength polyester fibers with low RFL permeability can be obtained.

However, although the other conditions are satisfied, the molecular weight of the component A is small and Comparative Examples 1, 10 to 12 which do not satisfy the conditions of the present invention show that the strength of the treated cord hardly increases even if the filament strength increases. , I do not get a satisfactory result. Even if the treating agent satisfies the conditions of the present invention, if the filament strength is low, the strength of the treated cord is low, which is not preferable.

Continuation of front page (56) Reference JP-A-60-9919 (JP, A) JP-A-58-98419 (JP, A) JP-A-63-59483 (JP, A)

Claims (1)

[Claims] (A) 62% by weight of a leveling agent (component A) containing a sulfur-containing ester compound having a molecular weight of 600 or more as a main component.
As described above, (b) 8% by weight or more of an ether type polymer activator (component B) having a molecular weight of 7,000 or more and 15 ° C., (c) a nonionic activator (component C) having a molecular weight of 800 or more and 2700 or less 20% by weight or less and A + B is 90% by weight or less, and a polyester fiber to which a treating agent is added, wherein the polyester fiber simultaneously satisfies the following (i)-(iii): High-strength polyester fiber that does. (I) Filament strength ≧ 8.5g / d (ii) Smoke emission ≦ 1500 (iii) RFL permeability ≦ 5cm