JP2005273034A - Radiator hose reinforcing fiber and radiator hose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiator hose reinforcing fiber having excellent coolant resistance at a high temperature and having sufficient durability, and a radiator hose using the fiber.
SOLUTION: A dicarboxylic acid component in which 60 mol% or more of the dicarboxylic acid component is an aromatic dicarboxylic acid and a diamine component in which 60 mol% or more of the diamine component is an aliphatic alkylenediamine having 6 to 12 carbon atoms are synthesized. A radiator hose reinforcing fiber comprising a fiber (A) containing polyamide (a) and having a strength retention of 90% or more after being immersed in a 50 wt% ethylene glycol solution at 120 ° C. for 20 days was used. Radiator hose.
[Selection figure] None

Description

  The present invention relates to an automotive radiator hose and its reinforcing fibers.

Conventionally, fibers such as nylon 6, nylon 66, para-aramid, polyvinyl alcohol, and polyester have been used as reinforcing fibers for automotive radiator hoses (see, for example, Patent Documents 1 to 4). However, the radiator hose using these reinforcing fibers has a problem in that the temperature of the radiator liquid at the time of use and the temperature of the engine room are high, so that the reinforcing effect cannot be sufficiently maintained over a long period of time and the hose life is short. There was a point.
In order to extend the hose life, it is necessary to improve the coolant resistance of the reinforcing fiber. Regarding the coolant resistance of the radiator hose, it is immersed in a 50 wt% ethylene glycol aqueous solution at 100 ± 1 ° C. for 7 days in JIS D2602. The hose hardness, tensile strength, elongation, and volume change are regulated within a certain range. However, in recent years, further improvement in durability is required for practical use and maintenance-free.

Japanese Patent Laid-Open No. 5-78907 JP-A-6-008376 JP-A-6-264322 JP 11-229275 A

  As a result of intensive studies, the present inventors have found that a dicarboxylic acid component in which 60 mol% or more of the dicarboxylic acid component is an aromatic dicarboxylic acid and a diamine component of 60 mol% or more are aliphatic alkylenediamine having 6 to 12 carbon atoms. It has been found that by using a polyamide fiber synthesized from a certain diamine component as a reinforcing fiber for a radiator hose, a radiator hose having excellent durability at high temperatures and sufficient durability can be produced.

  That is, the present invention is synthesized from a dicarboxylic acid component in which 60 mol% or more of the dicarboxylic acid component is an aromatic dicarboxylic acid and a diamine component in which 60 mol% or more of the diamine component is an aliphatic alkylenediamine having 6 to 12 carbon atoms. A fiber containing a polyamide (a) (A), and a reinforcing fiber for reinforcing a radiator hose having a strength retention of 90% or more after being immersed in a 50% by weight ethylene glycol solution at 120 ° C. for 20 days, Preferably, 60 mol% or more of dicarboxylic acid units of polyamide (a) are terephthalic acid units, and 60 mol% or more of diamine units are 1,9-nonanediamine units and / or 2-methyl-1,8-octanediamine units. The above-mentioned radiator hose reinforcing fiber is used, and more preferably, the above reinforcing fiber is used. On the automotive radiator hose.

  The technology of the present invention makes it possible to produce a radiator hose that has excellent coolant resistance at high temperatures and has sufficient durability.

  First, the polyamide (a) used for the radiator hose reinforcing fiber of the present invention will be described. The polyamide (a) comprises a dicarboxylic acid component and a diamine component, wherein 60 mol% or more of the dicarboxylic acid component is an aromatic dicarboxylic acid, and 60 mol% or more of the diamine component is an aliphatic alkylene having 6 to 12 carbon atoms. It is characterized by being a diamine.

  As the aromatic dicarboxylic acid, terephthalic acid is preferable in terms of heat resistance and coolant resistance of the fiber for reinforcing the hose of the radiator hose. Isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalene Dicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, dibenzoic acid, 4,4′-oxydibenzoic acid, diphenylmethane-4,4′-dicarboxylic acid, diphenyl Aromatic dicarboxylic acids such as sulfone-4,4′-dicarboxylic acid and 4,4′-biphenyldicarboxylic acid can be used alone or in combination of two or more. The content of the aromatic dicarboxylic acid needs to be 60 mol% or more of the dicarboxylic acid component, and is preferably 75 mol% or more. Examples of dicarboxylic acids other than the aromatic dicarboxylic acids include malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, and trimethyl. Aliphatic dicarboxylic acids such as adipic acid, pimelic acid, azelaic acid, sebacic acid and suberic acid; and alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid, These acids can be used alone or in combination of two or more. Especially, it is preferable that a dicarboxylic acid component is 100% aromatic dicarboxylic acid at points, such as heat resistance and coolant resistance. Furthermore, polyvalent carboxylic acids such as trimetric acid, trimesic acid, pyromellitic acid and the like can be contained within a range where fiberization is easy.

Further, 60 mol% or more of the diamine component is composed of an alkylene diamine having 6 to 12 carbon atoms, and examples of the aliphatic alkylene diamine include 1,6-hexanediamine, 1,8-octanediamine, and 1,9-nonanediamine. 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,2,4- Straight chain such as trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, or the like Examples include aliphatic diamines having side chains.
Of these, 1,9-nonanediamine, and a combination of 1,9-nonanediamine and 2-methyl-1,8-octanediamine are preferred in terms of coolant resistance.
The content of the aliphatic alkylene diamine needs to be 60 mol% or more of the diamine component, and is preferably 75 mol% or more, particularly 90 mol% or more from the viewpoint of coolant resistance.

  When 1,9-nonanediamine and 2-methyl-1,8-octanediamine are used in combination as the aliphatic alkylenediamine, 60 to 100 mol% of the diamine component is 1,9-nonanediamine and 2-methyl-1,8-. It consists of octanediamine, and the molar ratio is preferably the former: the latter = 30: 70 to 99: 1, particularly the former: the latter = 40: 60 to 95: 5.

The polyamide (a) used in the present invention preferably has a [CONH / CH ₂ ] ratio in the molecular chain of 1/2 to 1/8, particularly 1/3 to 1/5. By using the polyamide in this range, a radiator hose reinforcing fiber having excellent coolant resistance and heat resistance can be obtained.

  The intrinsic viscosity (value measured at 30 ° C. of concentrated sulfuric acid) of the polyamide (a) of the present invention is preferably 0.6 to 2.0 dl / g, more preferably 0.6 to 1.8 dl / g, 0.7-1.6 dl / g is preferable. Intrinsic viscosity polyamides within the above range have good melt viscosity characteristics when fiberized, and are excellent in the strength and coolant resistance of the resulting radiator hose reinforcing fibers.

  Furthermore, in the polyamide (a) of the present invention, it is preferable that 10% or more of the end groups of the molecular chain are sealed with an end-capping agent, 40% or more of the ends, and 70% or more of the ends are sealed It is preferable that By sealing the ends of the molecular chains, the resulting radiator hose reinforcing fibers have excellent strength, coolant resistance, and the like.

  If necessary, stabilizers such as copper compounds, colorants, UV absorbers, light stabilizers, antioxidants, antistatic agents, flame retardants, plasticizers, lubricants, crystallization rate retarders, and other polycondensation reactions It can be added at or after.

  A known melt spinning apparatus can be used for the production of the fiber (A) containing the polyamide (a) of the present invention. Although spinning and stretching can be made into fibers in two stages, it is economically preferable to perform spinning and stretching continuously. The obtained multifilament may be used as it is, but it can also be used as a cord by twisting it. Moreover, in order to improve adhesiveness with rubber, RFL treatment using a mixed solution of resorcin / formaldehyde initial condensate (RF) and rubber latex (L) as an adhesion treatment liquid can be performed. The fineness of the fiber (A) is preferably 1 to 100 dtex for single fibers and 100 to 3000 dtex for multifilaments.

  The radiator hose using the radiator hose reinforcing fiber of the present invention can be produced by a known ordinary production method. For example, ethylene / propylene / diene terpolymer (EPDM) or isobutylene / isoprene rubber (IIR) is used as the inner layer and the outer layer, and the reinforcing fiber of the present invention is used between the inner layer and the outer layer as the reinforcing layer. It is done. As a structure of the hose including the reinforcing fiber, a general structure such as a blade hose, a spiral hose, a knit hose, or a cloth hose is used.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples. In addition, each measured value in an Example is a value measured by the following method.

[Fineness, strength and elongation of fiber]
It measured according to JIS L1013.

[Coolant resistance]
Regarding the coolant resistance of radiator hoses, JIS D2602 regulates changes in hose hardness, tensile strength, elongation, and volume within a certain range after being immersed in a 50 wt% ethylene glycol aqueous solution at 100 ± 1 ° C for 7 days. . In the present invention, in order to examine the durability at a higher temperature, the reinforcing fiber was made to have coolant resistance with a strong retention rate (%) after dipping the reinforcing fiber in a 50 wt% ethylene glycol aqueous solution at 120 ° C. for 20 days.

[Example 1]
(1) Polyamide having a dicarboxylic acid component of 100 mol% terephthalic acid, a diamine component of 50 mol% of 1,9-nonanediamine, and 50 mol% of 2-methyl-1,8-octanediamine (intrinsic viscosity 0.8 dl / g, The terminal sealing rate was 91% and the melting point was 265 ° C.). The polyamide is melt kneaded with an extruder, discharged from a spinning nozzle at a spinning temperature of 300 ° C., taken up at a speed of 1000 m / min, drawn at a roller temperature of 130 ° C. and a hot plate temperature of 200 ° C., and a polyamide fiber of 1980 dtex / 300 f. Got.
(2) When the fiber properties and coolant resistance of the obtained polyamide fiber were measured, as shown in Table 1, it was excellent in high-temperature coolant resistance.

[Example 2]
(1) Polyamide having a dicarboxylic acid component of 100 mol% terephthalic acid, a diamine component of 80 mol% of 1,9-nonanediamine, and 20 mol% of 2-methyl-1,8-octanediamine (intrinsic viscosity 0.9 dl / g, A polyamide fiber was obtained in the same manner as in Example 1 except that the end sealing rate was 76% and the melting point was 305 ° C., and the polyamide was spun at a spinning temperature of 330 ° C.
(2) When the fiber properties and coolant resistance of the obtained polyamide fiber were measured, as shown in Table 1, it was excellent in high-temperature coolant resistance.

[Example 3]
Using the polyamide used in Example 1, a polyamide fiber of 550 dtex / 100f was obtained by the same spinning method. When the fiber properties and the coolant resistance of the obtained polyamide fiber were measured, as shown in Table 1, it was excellent in the high temperature coolant resistance.

[Comparative Example 1]
Fiber properties and coolant resistance of para-aramid fibers (DuPont, Kevlar 29, 1665 dtex / 1000f) were measured in the same manner as in Examples 1 to 3. As shown in Table 1, the initial strength was high, but the coolant resistance was high. It was inferior in nature.

[Comparative Example 2]
When the fiber physical properties and coolant resistance of nylon 66 fiber (manufactured by Asahi Kasei Corporation, Leona, 1870 dtex / 280f) were measured in the same manner as in Examples 1 to 3, they were inferior in coolant resistance as shown in Table 1.

[Comparative Example 3]
Fiber properties and coolant resistance of the polyester fibers (Kuraray, Kraftel, 1665 dtex / 300f) were measured in the same manner as in Examples 1 to 3, and as shown in Table 1, they were inferior in coolant resistance.

Polyamide (a) synthesized from a dicarboxylic acid component in which 60 mol% or more of the dicarboxylic acid component is an aromatic dicarboxylic acid and a diamine component in which 60 mol% or more of the diamine component is an aliphatic alkylenediamine having 6 to 12 carbon atoms A radiator hose reinforcing fiber having a strength retention of 90% or more after being immersed in a 50 wt% ethylene glycol solution at 120 ° C. for 20 days, and a radiator hose using the fiber can do.

Claims (3)

  Polyamide (a) synthesized from a dicarboxylic acid component in which 60 mol% or more of the dicarboxylic acid component is an aromatic dicarboxylic acid and a diamine component in which 60 mol% or more of the diamine component is an aliphatic alkylenediamine having 6 to 12 carbon atoms A fiber for reinforcing a hose of a radiator hose having a strength retention of 90% or more after being immersed in a 50 wt% ethylene glycol solution at 120 ° C. for 20 days.   60 mol% or more of the dicarboxylic acid units of the polyamide (a) are terephthalic acid units, and 60 mol% or more of the diamine units are 1,9-nonanediamine units and / or 2-methyl-1,8-octanediamine units. The radiator hose reinforcing fiber according to claim 1. An automotive radiator hose using the reinforcing fiber according to claim 1.