JP2010065779A - Automobile negative pressure resistant hose and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automobile negative pressure resistant hose superior in assembling workability, vibration absorption and flexibility, lighter, and superior in negative pressure resistance, and to provide a manufacturing method thereof. <P>SOLUTION: Negative pressure durable layers 2 as melted coat layers of fluororesin are formed in a belt shape peripherally on the outer periphery of the rubber hose 1 at fixed intervals. A rubber layer (the rubber hose 1) contacting the negative pressure durable layers 2 is formed of a rubber composition containing the following (A) component and the following (B)-(D) components: the (A) component is at least one rubber selected from a group consisting of EPDM, EPM, AEM, NBR, and NBR-PVC, the (B) component is a cresol compound, the (C) component is a melamine resin, and the (D) component is at least one peroxide vulcanizing agent selected from a group consisting of dicumyl peroxide, 2,5-dimethyl-2,5-di-t-buthylpeloxyhexane, and di-t-bythylpeloxy-diisopropylbenzene. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a negative pressure hose for automobiles and a method for producing the same, and more specifically, a refrigerant transport hose for automobiles (radiator hoses, heater hoses, cooling water hoses for fuel cell vehicles, etc.), hose for air piping ( The present invention relates to a negative pressure resistant hose useful as a turbo air hose, a blow-by gas hose, an emission control hose, a vacuum brake hose, and the like, and a manufacturing method thereof.

In general, a refrigerant hose such as a radiator hose or an air piping hose such as a turbo air hose used in an engine room of an automobile has a rubber hose in view of assembly workability, vibration absorption, flexibility, etc. Used. Conventionally, such a rubber hose has a layer structure in which a reinforcing yarn layer is formed on the outer peripheral surface of a tubular rubber inner layer, and a rubber outer layer is further formed on the outer peripheral surface (Patent Document 1 and 2).
Japanese Patent Laid-Open No. 7-68659 JP 2008-163488 A

  By the way, in radiators and the like, the circulation pressure of the internal fluid (cooling water, etc.) is increasing in order to improve the cooling efficiency and the like, and accordingly, in the piping behind the circulation pump (suction side) There is a tendency to apply negative pressure. Since the rubber hose disclosed in the above patent document has a reinforcing yarn layer, the pressure resistance performance against an increase in the internal pressure of the hose is high. However, when the reinforcing yarn layer is configured as described above, durability against negative pressure is hardly obtained. For this reason, when the rubber hose is used for the piping behind the pump, the negative pressure causes the hose to dent inside, closing the inside of the hose and narrowing the flow path, resulting in an internal fluid (cooling water, etc.) ) Flow is worse.

  Therefore, in order to ensure the durability (negative pressure resistance) against the negative pressure as described above, conventionally, for example, (1) the entire hose is made of a hard material, (2) the thickness of the entire hose is increased, (3) Methods such as forming the hose partly thick with a molding die, etc., (4) inserting a rigid material such as a metal ring inside the hose, and (5) responding by shortening the hose as much as possible are also being investigated. .

  However, in the methods (1) to (5) described above, characteristics such as assembly workability, vibration absorption, and flexibility that are characteristic of the rubber hose may be impaired.

  Moreover, when a hose is comprised by the above methods, there exists a possibility that the weight of a hose may increase. However, since the hose for automobiles is also required to reduce the weight of the hose for the purpose of improving the fuel consumption, there is a situation where it is desired to avoid an increase in the weight of the hose in order to increase the negative pressure resistance.

  The present invention has been made in view of such circumstances, and its object is to provide an automotive negative pressure hose that is excellent in assembly workability, vibration absorption and flexibility, is light in weight and excellent in negative pressure resistance, and a method for producing the same. And

In order to achieve the above object, the present invention provides a rubber hose having a single layer or a plurality of rubber layers, in which at least one of an inner periphery and an outer periphery is formed with a belt-like negative pressure durability layer at a predetermined interval in the circumferential direction. The negative pressure resistant hose for automobiles, wherein the negative pressure durable layer is a melted coating layer of a fluororesin, and the rubber layer in contact with the negative pressure durable layer is the following (B) The first gist is a negative pressure resistant hose for automobiles comprising a rubber composition containing the components (D) to (D).
(A) Ethylene-propylene-diene terpolymer rubber (EPDM), ethylene-propylene rubber (EPM), ethylene acrylic rubber (AEM), acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-butadiene rubber and polyvinyl chloride And at least one rubber selected from the group consisting of blended rubber (NBR-PVC).
(B) Cresol compound.
(C) Melamine resin.
(D) at least one peroxide vulcanization selected from the group consisting of dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane and di-t-butylperoxy-diisopropylbenzene Agent.

The present invention also relates to a method for producing a negative pressure resistant hose for automobiles according to the first aspect, wherein a rubber composition containing the following components (A) to (D) is steamed at 140 to 170 ° C. for 10 to 60 minutes. After producing a rubber hose having a rubber layer formed by vulcanization, the surface of the rubber layer is electrostatically coated with a fluorine-based resin powder in a band shape in the circumferential direction of the hose at a predetermined interval. The second gist is a method for producing a negative pressure resistant hose for automobiles in which a negative pressure durable layer is formed by melting the powder by oven heating for 30 minutes.
(A) Ethylene-propylene-diene terpolymer rubber (EPDM), ethylene-propylene rubber (EPM), ethylene acrylic rubber (AEM), acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-butadiene rubber and polyvinyl chloride And at least one rubber selected from the group consisting of blended rubber (NBR-PVC).
(B) Cresol compound.
(C) Melamine resin.
(D) at least one peroxide vulcanization selected from the group consisting of dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane and di-t-butylperoxy-diisopropylbenzene Agent.

  That is, the present inventors have intensively studied to solve the above problems. In the course of the research, the present inventors recalled that a thin negative pressure durability layer is formed in a strip shape in the circumferential direction of the hose on the inner periphery and outer periphery of the rubber hose. In addition, the present inventors have formed the above-described belt-like negative pressure durability layer at predetermined intervals with respect to the longitudinal direction of the hose (see FIGS. 1 and 2), and ensure the interlayer adhesion to prevent negative resistance. Recalling that it secures pressure characteristics and secures the characteristics of rubber hoses, such as assembly workability, vibration absorption and flexibility.

  More specifically, the present inventors, for the hose of the layer configuration as described above, in order to achieve weight reduction and improve negative pressure resistance, the negative pressure durability layer is a coating layer made of a fluororesin, In addition, the inventors conceived that the negative pressure resistance is improved by incorporating an adhesive component with the negative pressure durable layer on the rubber hose side to obtain adhesion between the negative pressure durable layer and the rubber hose. As a result of repeated research by the present inventors, as a material for the rubber layer to which the negative pressure durable layer is bonded, a specific rubber (A component) such as EPDM is added to a cresol compound (B component) as an adhesive component. And melamine resin (C component), and it was found effective to use a material containing a special peroxide vulcanizing agent (D component) having a high vulcanization rate. That is, in the rubber layer formed by vulcanization of this material, the adhesive component is not easily reacted (not easily vulcanized) when the rubber layer is formed (during steam vulcanization). Rubber vulcanization is completed before the components react sufficiently. For this reason, when a coating layer (negative pressure endurance layer) is formed by melting the fluororesin on the surface of the rubber layer, the unreacted adhesive component reacts during the formation of the molten coating layer. Therefore, the desired interlayer adhesion can be obtained between the rubber layer and the coating layer (negative pressure durability layer), and it has been determined that the intended purpose is achieved, and the present invention has been achieved.

  As described above, in the automotive negative pressure resistant hose of the present invention, a belt-shaped negative pressure durable layer is formed at predetermined intervals in the circumferential direction on at least one of the inner periphery and the outer periphery of a rubber hose having a single layer or a plurality of rubber layers. The negative pressure endurance layer is a fluororesin melt coating layer, and the rubber layer in contact with the negative pressure endurance layer is a predetermined rubber such as EPDM and a cresol system that is an adhesive component. It consists of a rubber composition containing a compound and a melamine resin and a special peroxide vulcanizing agent having a high vulcanization rate. Therefore, the negative pressure resistant hose for automobiles of the present invention has high adhesion to the rubber layer of the negative pressure durable layer and is excellent in negative pressure resistance. The hose of the present invention is excellent in assembling workability, vibration absorption and flexibility, and is light in weight. Therefore, the refrigerant transport hose for automobiles (radiator hoses, heater hoses, cooling water hoses for fuel cell vehicles, etc.) ) And air pipe hoses (turbo air hose, blow-by gas hose, emission control hose, vacuum brake hose, etc.) and the like.

  In particular, when the rubber hose is composed of a plurality of rubber layers and a reinforcing yarn layer is formed between the rubber layers, the pressure resistance against an increase in the internal pressure of the hose is improved.

  And in the manufacturing method of the negative pressure hose for automobiles of the present invention, a predetermined rubber such as EPDM, a cresol compound and a melamine resin as adhesive components, and a special peroxide vulcanizing agent having a high vulcanization speed are contained. A rubber hose provided with a rubber layer obtained by steam vulcanizing the rubber composition to be steamed at 140 to 170 ° C. for 10 to 60 minutes, and then fluorinated resin powder in a band shape in the hose circumferential direction with respect to the surface of the rubber layer Electrostatic coating at a predetermined interval, oven-heated at 180 to 250 ° C. for 10 to 30 minutes to melt the powder and form a negative pressure durable layer, and the negative resistance for automobiles having the excellent functions as described above. The pressure hose can be manufactured with high quality.

  Next, embodiments of the present invention will be described in detail.

The negative pressure resistant hose for automobiles of the present invention (hereinafter abbreviated as “negative pressure resistant hose”) has, for example, a belt-like negative pressure durable layer 2 formed in the circumferential direction on the outer periphery of a rubber hose 1 as shown in FIG. It will be. The rubber hose 1 includes a single layer or a plurality of rubber layers (not shown). The negative pressure endurance layer 2 is a molten coating layer of a fluororesin, and the rubber layer (in FIG. 1, the outermost layer of the rubber hose 1) in contact with the negative pressure endurance layer 2 is the following component (A) A special rubber composition containing the following components (B) to (D) is also included. In addition, as shown in FIG. 2, the strip | belt-shaped negative-pressure durable layer 2 may be formed in the inner periphery of the rubber hose 1 in the circumferential direction. However, in this case, it is necessary that the innermost layer of the rubber hose 1 is made of the special rubber composition. Moreover, the said negative pressure durable layer 2 may be formed in both the inner periphery and outer periphery of the said rubber hose 1 (not shown). In this case, both the innermost layer and the outermost layer of the rubber hose 1 are required to be made of the special rubber composition.
(A) Ethylene-propylene-diene terpolymer rubber (EPDM), ethylene-propylene rubber (EPM), ethylene acrylic rubber (AEM), acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-butadiene rubber and polyvinyl chloride And at least one rubber selected from the group consisting of blended rubber (NBR-PVC).
(B) Cresol compound.
(C) Melamine resin.
(D) at least one peroxide vulcanization selected from the group consisting of dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane and di-t-butylperoxy-diisopropylbenzene Agent.

  Among the rubbers of the component (A), ethylene-propylene-diene terpolymer rubber (EPDM) can be preferably used in the application of the refrigerant transport hose. Moreover, ethylene acrylic rubber (AEM) can be preferably used in the application of the air piping hose. The rubbers listed as the component (A) are used alone or in combination of two or more.

  Examples of the cresol compound (B component) used together with the component (A) include a cresol / formaldehyde condensate. This cresol compound hardly reacts during rubber vulcanization, and reacts effectively when forming a molten coating layer (negative pressure durability layer 2) of a fluororesin.

  The blending ratio of the cresol compound (component B) is preferably in the range of 0.1 to 10 parts, particularly preferably 100 parts by weight (hereinafter abbreviated as “part”) of the specific rubber (component A). Is 0.5 to 5 parts. That is, when the B component is less than the above range, the adhesiveness with the negative pressure durability layer 2 tends to be deteriorated. Conversely, when the B component exceeds the above range, the cost is increased.

  Examples of the melamine resin (component C) used together with the components (A) and (B) include methylated formaldehyde / melamine polymer, hexamethylenetetramine, and the like. These may be used alone or in combination of two or more.

  The compounding ratio of the cresol compound (B component) to the melamine resin (C component) is preferably in the range of B component / C component = 1 / 0.5 to 1/2, particularly preferably. Is B component / C component = 1 / 0.77 to 1 / 1.5. That is, when the weight ratio of the C component is less than 0.5, there is a tendency that the tensile strength (TB), elongation (EB), etc. of the hose (rubber layer) are slightly deteriorated. If the ratio exceeds 2, the adhesiveness is saturated and the adhesive strength is stabilized. Therefore, even if the weight ratio of the D component is further increased, only the cost is increased, and no further effect can be expected.

  As the peroxide vulcanizing agent (D component) used together with the above components (A) to (C), as mentioned above, dicumyl peroxide, 2,5-dimethyl-2,5-di-t Specific peroxide vulcanizing agents such as -butylperoxyhexane, di-t-butylperoxy-diisopropylbenzene are used. These may be used alone or in combination of two or more. Among these, dicumyl peroxide is preferably used from the viewpoint of completing rubber vulcanization at an early stage before the reaction of the adhesive component proceeds.

  The blending ratio of the peroxide vulcanizing agent (component D) is preferably in the range of 1.5 to 20 parts with respect to 100 parts of the specific rubber (component A). That is, when the D component is less than 1.5 parts, the vulcanization is insufficient and the strength of the hose (rubber layer) is inferior. Conversely, when the D component exceeds 20 parts, it becomes too hard and the flexibility of the hose. This is because the tendency to decrease is observed.

  In addition to the above components (A) to (D), carbon black, anti-aging agent, vulcanization accelerator, vulcanization aid, processing aid, white filler, plasticizer, softener, acid acceptor, A colorant, an anti-scorch agent, etc. may be added as appropriate.

  Here, when the rubber hose 1 has a single-layer structure, the layer needs to be made of a rubber composition containing the components (A) to (D). However, when a plurality of rubber layers are provided, the rubber layer in contact with the negative pressure durability layer 2 may be made of a rubber composition containing the components (A) to (D). These rubber layers can be formed by kneading the above components using a kneader such as a kneader or a Banbury mixer, and extruding the rubber composition obtained thereby.

  Moreover, when the said rubber hose 1 consists of a some rubber layer and comprises a reinforcement thread | yarn layer between the layers of the rubber layer, since it comes to be excellent in the pressure | voltage resistance with respect to the raise of a hose internal pressure, it is preferable. In this case, examples of the reinforcing yarn layer include aramid (aromatic polyamide) fiber, polyester fiber such as polyethylene terephthalate (PET), nylon (polyamide) fiber such as nylon 6, nylon 66, and polyvinyl alcohol (vinylon) fiber. The layer which consists of a reinforcing thread is mentioned. These may be used alone or in combination of two or more. Among these, an aramid yarn is preferably used from the viewpoints of durability by heat treatment at high temperature, pressure resistance, and interlayer adhesion.

  In addition, when comprising a reinforcement thread | yarn layer in the rubber hose 1 as mentioned above, the manufacturing method is performed as follows, for example. That is, first, an unvulcanized rubber inner layer is formed into a tubular (cylindrical) material by a method such as extrusion molding, injection molding, or transfer molding. Next, the reinforcing yarn layer is formed by braiding the reinforcing yarn (spiral winding, blade knitting, knitting knitting, etc.) on the outer peripheral surface of the rubber inner layer with a predetermined number of draws and driving numbers. Subsequently, a predetermined adhesive is appropriately applied to the outer peripheral surface of the reinforcing yarn layer by a dipping method, a spray method, a roll coating method, a brush coating method, etc., and then a rubber outer layer material is extruded. Forming an unvulcanized rubber outer layer. The mandrel is inserted into the unvulcanized hose structure thus obtained, steam vulcanized under predetermined conditions, and then removed from the mandrel so that a reinforcing yarn layer is formed on the outer peripheral surface of the rubber inner layer. A rubber hose 1 formed and having a rubber outer layer formed on the outer peripheral surface thereof can be produced.

  And as mentioned above, as a material of the negative pressure durable layer 2 formed in a belt shape in the circumferential direction on at least one of the inner periphery and the outer periphery of the rubber hose 1 obtained as described above, a fluorine-based material is used. Resin is used.

  Examples of the fluorine resin include ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer (THV), polyvinylidene fluoride (PVDF), tetrafluoroethylene- Hexafluoropropylene copolymer (FEP), ethylene-chlorotrifluoroethylene copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride- Tetrafluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene-perfluoroalkoxy vinyl ether copolymer, tetrafluoroethylene-vinyli Nfuruoraido - hexafluoropropylene - perfluoroalkoxy vinyl ether copolymer, and the like. These may be used alone or in combination of two or more. Especially, since it is excellent in heat resistance and a weather resistance, polyvinylidene fluoride (PVDF) is used suitably.

  And the negative pressure-resistant hose of this invention can be manufactured as follows, for example. That is, first, as described above, the rubber hose 1 is manufactured by extrusion molding, injection molding, transfer molding, or the like. The rubber hose 1 is subjected to steam vulcanization at 140 to 170 ° C. for 10 to 60 minutes so that the crosslinking reaction (vulcanization reaction) of the adhesive components (B and C components) in the rubber composition proceeds. This is preferable because the rubber vulcanization can be completed before the vulcanization. If the steam vulcanization temperature or vulcanization time is less than the above range, the vulcanization becomes sweet, the hose surface becomes sticky, and the quality deteriorates. Therefore, it is necessary to complete the rubber vulcanization according to the above conditions. There is. Next, at least one of the inner and outer circumferences of the rubber hose 1 is electrostatically coated with the fluororesin powder at predetermined intervals in a band shape in the hose circumferential direction, and then the oven is heated at 180 to 250 ° C. for 10 to 30 minutes. The negative pressure durable layer 2 is formed by heating and melting the powder. In addition, the thickness of the said negative pressure durable layer 2 can be controlled by increasing the frequency | count of the said coating. In this way, the intended negative pressure resistant hose can be obtained.

  The electrostatic coating is usually performed with a coating gun. Electrostatic coating on the inner peripheral surface of the rubber hose 1 is performed by inserting an extension nozzle of a coating gun into the rubber hose 1.

  In addition, before electrostatic coating of the fluororesin powder, the surface of the rubber hose 1 that is the coating surface is wiped and washed with an organic solvent (alcohol, toluene, etc.), so that the bloom or deposits on the hose surface It is preferable from the viewpoint of taking off and further strengthening the interlayer adhesion.

  Moreover, when generation | occurrence | production of the turbulent flow of the internal fluid in a hose becomes a problem, it is preferable to form the negative pressure durable layer 2 only with respect to the outer periphery of the rubber hose 1. FIG.

  Further, if necessary, the surface of the rubber hose 1 to be the coated surface is appropriately coated with the same adhesive component (components B and C) in the rubber composition diluted in an organic solvent, and interlayer adhesion is obtained. It is also possible to increase.

  In the negative pressure resistant hose of the present invention thus obtained, the interval between the negative pressure durable layers 2 adjacent to each other in the longitudinal direction of the hose is normally set to about 15 cm or less. From the viewpoints of flexibility, weight reduction, negative pressure resistance, etc., the range is preferably 3 to 10 cm. In addition, the width (length) of the negative pressure durability layer 2 with respect to the longitudinal direction of the hose is usually set to 2 cm or more, preferably from the viewpoint of vibration absorption, flexibility, weight reduction, negative pressure resistance, etc. It is in the range of 3 to 10 cm. In addition, in order to make assembly workability | operativity favorable, it is also possible not to form the said negative pressure durable layer 2 in a hose edge part (fastening part). In addition, the negative pressure durability layer 2 may not be formed in the hose bent portion so as to ensure sufficient flexibility in accordance with the bent shape of the hose.

  The thickness of the negative pressure durability layer 2 is preferably in the range of 10 to 1000 μm, and more preferably in the range of 50 to 200 μm. That is, by setting in this way, the negative pressure resistance of the hose can be ensured satisfactorily while eliminating the increase in the weight of the hose.

  The negative pressure resistant hose of the present invention is excellent in assembling workability, vibration absorption and flexibility, and is lightweight, so it is a refrigerant transport hose for automobiles (radiator hoses, heater hoses, cooling water hoses for fuel cell vehicles, etc.) ) And air pipe hoses (turbo air hose, blow-by gas hose, emission control hose, vacuum brake hose, etc.) and the like. And from a viewpoint of using as a thing suitable for these uses, it is preferable that the thickness of the rubber hose 1 is 2-6 mm, Most preferably, it is 3-5 mm. And from a viewpoint of using as a thing suitable for said use, the inside diameter of a hose is within the range of 4-100 mm, Most preferably, it exists in the range of 10-50 mm.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

  First, prior to the examples and comparative examples, the following materials were prepared.

[EPDM]
Esplen 552, manufactured by Sumitomo Chemical Co., Ltd.

〔Carbon black〕
SRF Carbon Black, Show Black IP-200, Showa Cabot

〔oil〕
Paraffin oil, Diana Process PW-380, manufactured by Idemitsu Kogyo Co., Ltd.

[Cresol compounds]
Sumikanol 610, manufactured by Taoka Chemical Co., Ltd.

[Resorcinol compound]
Sumikanol 620, manufactured by Taoka Chemical Industries

[Melamine resin]
Sumikanol 507AP, manufactured by Taoka Chemical Industries

[Peroxide vulcanizing agent (i)]
Dicumyl peroxide (Park Mill D-40B, manufactured by NOF Corporation)

[Peroxide vulcanizing agent (ii)]
2,5-dimethyl-2,5-di-t-butylperoxyhexane (Perhexa 25B-40, manufactured by NOF Corporation)

[Peroxide vulcanizing agent (iii)]
Perbutyl P40-MB (K), manufactured by NOF Corporation

[Examples 1 to 10, Comparative Examples 1 to 4]
First, each of the prepared component materials is blended in the proportions shown in Tables 1 and 2 below, and kneaded using an open roll or a closed mixer such as a kneader or a Banbury mixer to obtain a rubber composition. Prepared. This rubber composition was extruded into a tubular (cylindrical) shape having an inner diameter of 30 mm and a wall thickness of 4 mm, and then cut to a length of 300 mm, and a straight metal mandrel having an outer diameter of 30 mm was inserted. And after performing steam vulcanization for 40 minutes at 160 degreeC, it extracted from the metal mandrel and obtained the rubber hose. Next, the outer periphery of the rubber hose was electrostatically coated with a fluororesin powder (Kureha KF Polymer, manufactured by Kureha Chemical Industry Co., Ltd.) in a band shape in the circumferential direction of the hose with a width of 5 cm and an interval of 5 cm with respect to the longitudinal direction of the hose ( After that, the powder was melted by oven-heating at 210 ° C. for 15 minutes to form a negative pressure durable layer having a thickness of 100 μm. In this way, the intended negative pressure resistant hose was manufactured.

  Various characteristics were measured and evaluated according to the following methods using the hoses thus obtained. These results are shown in Tables 3 and 4 below.

(Interlayer adhesion)
A sample was prepared by cutting a strip with a width of 10 mm along the circumferential direction in the negative pressure durable layer forming portion on the outer peripheral surface of the hose. Then, using a tensile tester (JIS B 7721), the negative pressure durability layer was peeled off from the end of the cut at a rate of 50 mm per minute, and the peel strength (N / 25 mm) was measured. The standard of the present invention is 15 N / 25 mm or more. In addition, the case where the peel strength exceeds 30 N / 25 mm is indicated as “30 <”. In addition, the peeled state at this time was visually observed, and the peeled surface was evaluated as ◯, the peeled surface was mostly broken as △, and the peeled surface was evaluated as ×. .

[Negative pressure resistance]
Each hose was connected to a decompression device, and the inside of the hose was gradually brought into a negative pressure state under a room temperature environment (25 ° C.) and a high temperature environment (80 ° C.). When the inside of the hose is blocked, the negative pressure strength is 60 kPa or more in a room temperature environment and 40 kPa or more in a high temperature environment, and the negative pressure does not satisfy this reference value. The blockage was evaluated as x.

  From the above results, all the products of the examples were excellent in interlayer adhesion and excellent in negative pressure resistance in a room temperature environment and a high temperature environment.

  On the other hand, all of the comparative products exhibited almost no interlayer adhesion and were inferior in negative pressure resistance.

  By the way, in accordance with Example 1, a negative pressure endurance layer having the same thickness as that of the example was formed on the entire outer peripheral surface of the rubber hose. As a result of measuring according to the above [negative pressure resistance] measurement standard, the inside of the hose was blocked. The negative pressure strength at that time was 60 kPa under a room temperature environment and 45 kPa under a high temperature environment. Therefore, even when a negative pressure endurance layer is formed on the entire outer peripheral surface of the rubber hose, or even when a negative pressure endurance layer is partially formed as in all examples, the negative pressure endurance It turned out that there was almost no change in performance.

  In the examples, the negative pressure durability layer is formed on the outer peripheral surface of the rubber hose, but as shown in FIG. 2, even when the negative pressure durability layer is formed on the inner peripheral surface of the rubber hose, As in the examples, it was confirmed by experiments that results excellent in each of the above characteristics were obtained. In addition, the rubber used in the examples is EPDM. However, when EPM, AEM, NBR, and NBR-PVC are used instead, the same results as the above examples can be obtained. This was confirmed by experiments. Further, even when di-t-butylperoxy-diisopropylbenzene is used in place of the peroxide vulcanizing agent used in the examples, similar to the examples, results excellent in each of the above characteristics can be obtained. This was confirmed by experiments.

  The negative pressure resistant hose of the present invention is a refrigerant transport hose for automobiles (radiator hoses, heater hoses, cooling water hoses for fuel cell vehicles, etc.), air piping hoses (turbo air hoses, blow-by gas hoses, emission control). Hose, vacuum brake hose, etc.).

It is a block diagram which shows an example of the negative pressure hose for motor vehicles of this invention. It is a block diagram which shows the other example of the negative pressure-resistant hose for motor vehicles of this invention.

Explanation of symbols

1 Rubber hose 2 Negative pressure durability layer

Claims (10)

A negative pressure resistant hose for automobiles, in which a belt-shaped negative pressure durable layer is formed at a predetermined interval in a circumferential direction on at least one of an inner periphery and an outer periphery of a rubber hose having a single layer or a plurality of rubber layers, A rubber composition in which the pressure durability layer is a molten coating layer of a fluororesin, and the rubber layer in contact with the negative pressure durability layer contains the following components (B) to (D) together with the following components (A): A negative pressure resistant hose for automobiles, characterized by comprising:
(A) Ethylene-propylene-diene terpolymer rubber (EPDM), ethylene-propylene rubber (EPM), ethylene acrylic rubber (AEM), acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-butadiene rubber and polyvinyl chloride And at least one rubber selected from the group consisting of blended rubber (NBR-PVC).
(B) Cresol compound.
(C) Melamine resin.
(D) at least one peroxide vulcanization selected from the group consisting of dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane and di-t-butylperoxy-diisopropylbenzene Agent.   In the rubber composition forming the rubber layer in contact with the negative pressure durability layer, the content ratio of the component (B) is in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the component (A). Item 1. A negative pressure resistant hose for automobiles according to Item 1.   In the rubber composition forming the rubber layer in contact with the negative pressure durability layer, the content ratio of the component (B) and the component (C) is (B) / (C) = 1 / 0.5 in weight ratio. The negative pressure-resistant hose for automobiles according to claim 1 or 2, which is in a range of ~ 1/2.   In the rubber composition forming the rubber layer in contact with the negative pressure durability layer, the content ratio of the component (D) is in the range of 1.5 to 20 parts by weight with respect to 100 parts by weight of the component (A). The negative pressure resistant hose for automobiles according to any one of Items 1 to 3.   The negative pressure-resistant hose for automobiles according to any one of claims 1 to 4, wherein the negative pressure durability layer is a melted coating layer of polyvinylidene fluoride (PVDF).   The negative pressure-resistant hose for automobiles according to any one of claims 1 to 5, wherein the negative-pressure durable layer has a thickness in a range of 10 to 1000 µm.   The negative pressure-resistant hose for automobiles according to any one of claims 1 to 6, wherein the rubber hose includes a plurality of rubber layers, and a reinforcing yarn layer is formed between the rubber layers.   It is a hose for refrigerant transportation or a hose for air piping, The negative pressure-resistant hose for motor vehicles as described in any one of Claims 1-7. It is a manufacturing method of the negative pressure hose for motor vehicles as described in any one of Claims 1-8, Comprising: The rubber composition containing the following (A)-(D) component is 140-170 degreeC for 10 to 60 minutes. After producing a rubber hose having a rubber layer formed by steam vulcanization, the surface of the rubber layer is electrostatically coated with a fluorine resin powder in a band shape in the circumferential direction of the hose at a predetermined interval. A method for producing a negative pressure resistant hose for an automobile, wherein the negative pressure durable layer is formed by melting the powder by oven heating for 30 minutes.
(A) Ethylene-propylene-diene terpolymer rubber (EPDM), ethylene-propylene rubber (EPM), ethylene acrylic rubber (AEM), acrylonitrile-butadiene copolymer rubber (NBR), acrylonitrile-butadiene rubber and polyvinyl chloride And at least one rubber selected from the group consisting of blended rubber (NBR-PVC).
(B) Cresol compound.
(C) Melamine resin.
(D) at least one peroxide vulcanization selected from the group consisting of dicumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane and di-t-butylperoxy-diisopropylbenzene Agent.   The method for producing a negative pressure resistant hose for an automobile according to claim 9, wherein the surface of the rubber hose to be coated is wiped and washed with an organic solvent before electrostatic coating of the fluororesin powder.

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