JP4280281B2 - Hot water supply hose - Google Patents

Description

  The present invention relates to a resin hose for housing equipment, and more particularly to a water supply hot water supply hose that is used for household water supply piping and the like and is also suitable for transporting hot water.

  In recent years, it has been common to provide a hot water supply facility as a water supply facility for a house. With such a hot water supply device, for example, a single lever-type faucet or the like supplies water to a sink or a washstand provided in a kitchen. Both are configured to be possible. Conventionally, copper or stainless steel pipes and corrugated pipes have been used for pipes for transporting such hot water, but recently, tubes made of thermoplastic resin, elastomer, rubber, etc. are easy to install. In many cases, a hot and cold water supply hose made of braided stainless steel wire and reinforced yarn has been used on the outer periphery of the wire.

  On the other hand, in the housing market equipped with such hot and cold water supply facilities, long-term compensation exceeding 50 years has been required for the housing itself, and accordingly, piping material that forms part of the housing. However, there has been an increasing demand for a long life span of 50 years or more from around 15 years in the past. Here, the actual life means an average usable period when a general home runs a normal life in a residential environment where a person actually lives and uses a water supply hot water supply hose.

  However, because sodium hypochlorite is added to tap water as a disinfectant in accordance with the Water Supply Law, polyethylene pipes that have been used extensively as resin hoses for initial hot water and hot water have been used for about 10 years. Occurrence of water bubbles and internal peeling occurred, the mechanical strength decreased with the progress of such deterioration, and there was a case in which a burst due to water pressure was finally generated.

A conventional technique for improving the chlorine resistance and extending the life of such a resin hose for water and hot water supply will be described below. First, the silane cross-linked polyethylene pipe according to the prior art 1 is a silane cross-linked polyethylene pipe having a gel fraction of 65% or more, and the weight average molecular weight Mw of the xylene-dissolved portion which is an uncrosslinked portion in the gel fraction test based on JIS K6769 is 1. X10 ⁵ or more, and the ratio Mw / Mn of the weight average dissolved amount Mw of the xylene-dissolved portion and the number average amount Mn of the xylene-dissolved portion is 3 or more (see Patent Document 1).

  However, such silane-crosslinked polyethylene pipes according to the conventional examples have improved chlorine resistance in room temperature tap water and warm water, and generation of water bubbles and internal peeling hardly occur, but the actual life is at most about 15 years. However, it was far from the target actual life of the present invention.

  Next, the prior art 2 for improving the chlorine resistance and extending the life of the resin hose for water / hot water supply will be described with reference to FIG. FIG. 10 is a partially cutaway perspective view of a water and hot water supply hose according to Prior Art 2. FIG.

The water and hot water supply hose according to prior art 2 is a hose comprising an inner surface layer tube 11 composed of at least an inner layer 12 and an outer layer 13 and a reinforcing layer 14 surrounding the outer layer 13. The inner layer 12 is a polyolefin-based resin layer containing 30 to 50,000 ppm of an antioxidant and a thickness of 0.03 to 0.5 mm, and the outer layer 13 is a thermoplastic elastomer or vulcanized rubber having flexibility. Furthermore, the amount of the anti-aging agent contained in the outer layer 13 of the inner surface layer tube 11 is contained in a range of 0.1 to 5 times the amount of the anti-aging agent contained in the inner layer 12 ( Patent Document 2).
Japanese Patent No. 3682304 Japanese Patent Laid-Open No. 10-2466

  However, the water supply hot water supply hose according to the prior art 2 is a polyolefin-based resin layer in which the inner layer 12 contains 30 to 50,000 ppm of an anti-aging agent and has a thickness of 0.03 to 0.5 mm, and the outer layer 13 Since it is composed of a thermoplastic elastomer having flexibility, it can be improved over the hose according to the prior art 1 and reaches an actual life of about 20 years, but it can achieve a long life of 50 years or more as described above. It is not a thing.

Therefore, the present invention has been made in view of the above circumstances, and its purpose is as follows.
The object is to provide a hot water and hot water supply hose that has flexibility, is excellent in heat aging resistance and chlorine resistance, and has a predicted life span of 50 years or more.

The means adopted by the hot water supply / hot water hose according to claim 1 of the present invention is a water supply / hot water supply hose comprising an inner surface layer tube comprising at least an inner layer and an outer layer, and a reinforcing layer formed around the outer layer of the inner surface layer tube. The inner layer of the inner surface layer tube is a crosslinked polyethylene resin having a thickness of 0.1 to 1.0 mm, the outer layer of the inner surface layer tube is a thermoplastic elastomer having rubber elasticity, and the soft segment of the thermoplastic elastomer The degree of crosslinking is 90% or more.

  According to a second aspect of the present invention, there is provided a water supply / hot water hose according to the first aspect of the present invention, wherein the thermoplastic elastomer is a polyolefin-based thermoplastic elastomer and the soft segment is an ethylene-propylene-diene. It is a monomer rubber (EPDM).

According to a third aspect of the present invention, there is provided a water / hot water supply hose according to the first or second aspect of the present invention, wherein the thermoplastic elastomer has a dispersed phase of EPDM particles dynamically crosslinked to a polypropylene matrix. It is a dynamic cross-linked thermoplastic elastomer formed .

  According to a fourth aspect of the present invention, there is provided the water supply hot water supply hose according to any one of the first to third aspects, wherein the inner layer and the outer layer of the inner surface layer tube are provided with an anti-aging agent. In addition, an anti-aging agent (anti-aging agent for outer layer) different from the anti-aging agent (anti-aging agent for inner layer) contained in the cross-linked polyethylene resin constituting the inner layer was used for the thermoplastic elastomer constituting the outer layer. It is characterized by this.

According to claim 5 of the present invention, the water supply hot water supply hose according to claim 5 is the water supply hot water supply hose according to claim 4 , wherein the anti-aging agent for the inner layer is an ultraviolet absorber, and the anti-aging agent for the outer layer is a phenol type. It is an anti-aging agent comprising an antioxidant and a phosphorus-based antioxidant.

According to the water supply hot water supply hose according to claim 1 of the present invention, in the water supply hot water supply hose comprising an inner surface layer tube comprising at least an inner layer and an outer layer, and a reinforcing layer formed around the outer layer of the inner surface layer tube, The inner layer of the layer tube is a crosslinked polyethylene resin having a thickness of 0.1 to 1.0 mm, the outer layer of the inner surface layer tube is a thermoplastic elastomer having rubber elasticity, and the degree of crosslinking of the soft segment of the thermoplastic elastomer Is 90% or more, it is possible to provide a long-life and flexible water supply hot-water supply hose that has excellent workability, chlorine resistance and heat aging resistance.

  Moreover, according to the hot water supply / hot water hose according to claim 2 of the present invention, the thermoplastic elastomer is made of a polyolefin-based thermoplastic elastomer, and the soft segment is ethylene-propylene-diene monomer rubber (EPDM). High flexibility and bending fatigue resistance can be imparted to the outer layer of the layer tube.

Further, according to the hot water and hot water supply hose according to claim 3 of the present invention, the thermoplastic elastomer is a dynamically crosslinked thermoplastic elastomer in which a dispersed phase of EPDM particles dynamically crosslinked is formed on a polypropylene matrix. A water and hot water supply hose that is particularly excellent in water resistance, weather resistance, chemical resistance, heat fatigue resistance, and bending fatigue resistance can be provided.

Further, according to the hot water supply / hot water hose according to claim 4 of the present invention, the inner layer and the outer layer of the inner surface layer tube contain an anti-aging agent, and the thermoplastic elastomer constituting the outer layer constitutes the inner layer. Because we used an anti-aging agent (anti-aging agent for the outer layer) different from the anti-aging agent (anti-aging agent for the inner layer) contained in the crosslinked polyethylene resin,
Even if the inner layer anti-aging agent remains in the inner layer, the concentration gradient to the inner layer side of the outer layer anti-aging agent is irrelevant. Diffusion to the inner layer side is promoted and aging prevention is more effectively promoted.

  Furthermore, according to the hot water supply hot water hose according to claim 5 of the present invention, the anti-aging agent for the inner layer is an ultraviolet absorber, and the anti-aging agent for the outer layer is a phenol-based antioxidant and a phosphorus-based antioxidant. Therefore, a synergistic effect is exhibited by combining different antioxidants.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a partially cutaway perspective view showing a laminated structure of a water and hot water supply hose according to an embodiment of the present invention, FIG. 2 is a structural explanatory view schematically showing the structure of a dynamically crosslinked thermoplastic elastomer, and FIG. 3 is an outer layer Schematic explanatory diagram for explaining the effect of using an anti-aging agent different from the anti-aging agent for the inner layer as the anti-aging agent for the inner layer, FIG. 4 explains the change in the cross-linked PE thickness and the remaining anti-aging agent over time It is a typical explanatory view for this.

  In FIG. 1, a water and hot water supply hose 1 according to an embodiment of the present invention includes an inner surface layer tube 2 composed of an inner layer 2 a and an outer layer 2 b, a reinforcing layer 3 formed around the outer layer of the inner surface layer tube 2, and the reinforcement It consists of the outer surface resin layer 4 coat | covered with the layer. And the inner layer 2a of the said inner surface layer tube 2 of such a hot-water supply hot water hose 1 consists of a crosslinked polyethylene resin, and the outer layer 2b of the said inner surface layer tube 2 is comprised from the thermoplastic elastomer which has a softness | flexibility.

  The reinforcing layer 3 provided on the outer periphery of the inner surface layer tube 2 includes an inner surface fiber layer 3a and an outer surface fiber layer 3b. The inner fiber layer 3a is formed by winding a plurality of reinforcing yarns while winding the reinforcing yarns while crossing the outer peripheral surface of the inner layer tube 2 so as to cross each other. The reinforcing yarn is preferably constructed by twisting a plurality of nylon yarns.

  Further, the outer surface fiber layer 3b is formed by winding a stainless steel wire while being crossed and braided on the outer peripheral surface of the inner surface fiber layer in terms of strength and rust resistance. Furthermore, the outer surface resin layer 4 is a resin layer for protecting the outer surface of the water / hot water supply hose, and the material is not particularly limited. For example, polypropylene or urethane thermoplastic elastomer is used as the reinforcing layer 3. It is formed so as to cover the outer periphery.

Next, the inner layer 2a and the outer layer 2b constituting the inner surface layer tube 2 will be described in detail below.
First, the crosslinked polyethylene resin constituting the inner layer 2a of the inner surface layer tube 2 can be obtained by adding a crosslinking agent to reactive polyethylene (PE) and melt-extruding it. This cross-linked polyethylene resin refers to ultrahigh molecular weight polyethylene having a three-dimensional network structure formed by bonding portions of chain-structured polyethylene as a thermoplastic plastic. Therefore, when the crosslinking reaction is completed, the polyethylene has a three-dimensional network structure like a thermosetting resin, and the inner layer 2a excellent in heat aging resistance, chemical resistance, environmental stress cracking performance and creep performance is obtained.

  Such a cross-linked polyethylene resin constituting the inner layer 2a of the inner surface layer tube 2 exhibits excellent characteristics in terms of water quality maintenance and food hygiene due to its excellent chemical stability, and has requirements as a piping material for drinking water. ing. The inner layer 2a made of the cross-linked polyethylene resin has not only the chlorine resistance against residual chlorine of sodium hypochlorite contained in tap water, but also a large elongation below freezing point and a good freeze resistance. The thickness of the inner layer 2a made of such a crosslinked polyethylene resin is preferably in the range of 0.1 to 1.0 mm, and more preferably in the range of 0.2 to 0.8 mm.

  By setting the thickness of the inner layer 2a as described above, the hot water supply / water supply hose 1 that can be applied for a long time in a wide temperature range from room temperature to 95 ° C. can be obtained. Table 1 shows the molding processability, chlorine resistance, and flexibility for each thickness configuration when the total thickness of the inner surface layer tube 2 is 1.2 mm and the thickness configurations of the inner layer 2a and the outer layer 2b are changed. This is a summary of evaluation results of examples and the like.

  That is, as shown in Table 1, when the thickness of the inner layer 2a made of a crosslinked polyethylene resin is less than 0.1, extrusion processing is difficult, and even if it can be molded into a tube shape, hypochlorous acid contained in tap water Chlorine resistance to acid soda is insufficient. On the other hand, if the thickness of the inner layer 2a exceeds 1.0 mm, the molding processability is poor and the inner surface layer tube 2 becomes hard and the flexibility as a hot water supply / hot water hose is lost.

Next, in the thermoplastic elastomer constituting the outer layer 2b of the inner surface layer tube 2,
Elastomers as exemplified in Table 2, namely, polyurethane-based thermoplastic elastomer (TPU), polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyester-based thermoplastic elastomer (TPEE), vinyl chloride-based Thermoplastic elastomer (TPVC), polyamide thermoplastic elastomer (TPAE), etc. can be used.

  Such a thermoplastic elastomer has both the characteristics of a crosslinked elastomer and the processability of the plastic. That is, a thermoplastic elastomer is a rubber elastic body that melts when heated and hardens when cooled. A molded product made of a thermoplastic elastomer exhibits useful properties such as shape retention at high temperature, elastic deformation during stretching and compression, and the like.

  According to the theory of elastomers, the polymer chain of a thermoplastic elastomer needs to contain two types of units or segments. One is a segment having fluidity in an amorphous state when the temperature range in which an elastomer is normally used is above the glass transition temperature. These segments are called soft segments (soft portions) and give the resulting material elastic properties (rubber elasticity).

  The other is called a hard segment (hard portion), and the hard segments associate with each other through intermolecular interactions. This segment is solid in the operating temperature range and fixes the arrangement of the polymer chains (physical crosslinking). At high temperatures, physical bonds dissociate and flow under stress in the same way as ordinary thermoplastics.

  And it is preferable that the crosslinking degree of the soft segment of such a thermoplastic elastomer which comprises the outer layer 2b of the said inner surface layer tube 2 is 90% or more. This is because if the degree of crosslinking is less than 90%, it cannot withstand long-term use in terms of chlorine resistance and heat resistance.

  In addition, the thermoplastic elastomer according to the present invention may be made of the above-mentioned materials, and among them, in particular, a polyolefin-based thermoplastic elastomer (TPO) from the viewpoint of water resistance, heat resistance and chlorine resistance. And the soft segment is preferably ethylene-propylene-diene monomer rubber (EPDM).

  Further, such TPO is obtained by a dynamic crosslinking method in which polypropylene (PP) and EPDM are mixed with a crosslinking agent and melt-extruded by a twin-screw extruder, and dispersion and crosslinking are simultaneously progressed in the extrusion process. More preferably, it is a crosslinked thermoplastic elastomer. As shown in FIG. 2, this dynamically cross-linked thermoplastic elastomer 5 has a structure in which EPDM particles 5b dynamically cross-linked to a PP matrix 5a are finely dispersed, and has excellent rubber elasticity, heat aging resistance and chemical resistance. This is because it is particularly excellent in resistance, bending fatigue resistance, water resistance and the like.

  The dynamic crosslinked thermoplastic elastomer has a larger blending amount of EPDM, which is a soft segment, than PP, which is a hard segment, but even if the blending amount is large, the soft segment forms a dispersed phase, Gives excellent flexibility. As the cross-linking agent, an organic oxide or a phenol resin cross-linking agent can be used, but TPO having a high strength and a cross-linking degree of 95% or more can be obtained by dynamic cross-linking using the phenol resin cross-linking agent.

Here, the method for measuring the degree of crosslinking of the soft segment will be described according to the following procedure. The following parentheses indicate the substance names when the thermoplastic elastomer is TPO.
(1) First, about 200 mg of a soft segment (EPDM) sample is weighed and finely cut.
(2) The obtained strip is put into a container containing 100 mL of solvent (cyclohexane), sealed and immersed for 48 hours at room temperature.

(3) The sample after immersion is taken out on a filter paper and dried under reduced pressure in a vacuum dryer at a temperature of 105 ° C. for 1 hour.
(4) The degree of cross-linking of the soft segment (EPDM) phase using the dry residue weight (EPDM) excluding the weight of the solvent-insoluble component from the dry residue weight and the theoretical soft segment (EPDM) weight before immersion (%) ) Is obtained from the following equation (1).
Cross-linking degree of soft segment = {dry residue weight (EPDM portion) / theoretical soft segment (EPDM) weight before immersion} × 100 (1)

  The hot water supply hose 1 according to the present invention is formed by melting and extruding the inner layer 2a and the outer layer 2b constituting the inner surface layer tube 2 using the double-layer extrusion mold as described above into a tube shape. It is important to improve the adhesion between the layers. Of course, several intermediate layers may be formed between the inner surface layer 2a and the outer surface layer 2b.

  And as for the hot water supply hot water hose 1 which concerns on this invention, while the inner layer 2a and the outer layer 2b of the said inner surface layer tube 2 contain an anti-aging agent, the thermoplastic elastomer which comprises the said outer layer 2b comprises the said inner layer 2a. It is preferable to use an anti-aging agent (anti-aging agent for outer layer) different from the anti-aging agent (anti-aging agent for inner layer) contained in the crosslinked polyethylene resin.

  That is, as an anti-aging agent (anti-aging agent for inner layer) contained in a commercially available cross-linked polyethylene resin, an ultraviolet absorber is usually included, but the thermoplastic elastomer constituting the outer layer 2b includes a phenol-based one. It is preferable to use an anti-aging agent (anti-aging agent for outer layer) comprising an antioxidant and a phosphorus-based antioxidant. For example, 2.6-di-tertiary-butyl-4-methylphenol is used as the phenol-based antioxidant, and tris (nonylphenyl) phosphite is used as the phosphorus-based antioxidant. I can do it.

  Thus, the thermoplastic elastomer constituting the outer layer 2b has an anti-aging agent (anti-aging agent for outer layer) different from the anti-aging agent (anti-aging agent for inner layer) contained in the crosslinked polyethylene resin constituting the inner layer 2a. The effect of using will be described in order with the passage of time with reference to FIG.

(1) First, in the stable period of initial use, the anti-aging agent effectively acts on radicals, active oxygen, copper ions, etc. in water and hose deterioration does not progress (see FIG. 3 (a)). .
(2) Although the progress of deterioration is started, the crosslinked PE constituting the inner layer 2a does not lead to main chain cleavage due to crosslinking of the PE polymer. The anti-aging agent for the inner layer in the inner layer 2a is gradually consumed against the attack factors contained in the hot water and tap water, and accordingly, the outer layer anti-oxidant in the outer layer 2b diffuses and moves to the inner layer 2a side. (See FIG. 3B).

(3) The anti-aging agent for the inner layer is consumed quantitatively, and the anti-aging agent for the outer layer diffuses and moves to the inner layer 2a side, while the whitening layer 6 is formed on the cross-linked PE inner surface constituting the inner layer 2a, Material deterioration such as generation of cracks 7 is accelerated (FIG. 3C).
(4) When the attacking factor cannot be prevented by the crosslinked PE layer constituting the inner layer 2a, the deterioration of the TPE layer on the outer layer 2b side also starts (FIG. 3D).
(5) When the deterioration further proceeds and the pressure resistance as the inner surface layer tube 2 cannot withstand the water pressure in the pipe, the hose is ruptured (FIG. 3E).

  And the reason for using an anti-aging agent different from the anti-aging agent for the inner layer as the anti-aging agent for the outer layer is that the concentration gradient of the anti-aging agent between the inner layer 2a and the outer layer 2b from the beginning, regardless of the progress of deterioration. This is because smooth transition (diffusion) of the anti-aging agent from the outer layer 2b side to the inner layer 2a side as described in the above section (2) is achieved. As a result, as will be clarified in Examples described later, when an anti-aging agent different from the anti-aging agent for the inner layer is added to the outer layer 2b, the hose life is 20 to 20 times longer than when the anti-aging agent is not added. It can extend the life by 30%.

  Next, the deterioration process of the inner surface layer tube 2 composed of the inner layer 2a and the outer layer 2b will be described with reference to FIG. FIG. 4 is a schematic explanatory diagram for explaining a deterioration process of the inner surface layer tube with the elapsed time. The water supply hot water hose having the above-described configuration starts to consume the anti-aging agent at the start of use, and from around time A when the anti-aging agent is consumed, the whitening of the crosslinked PE begins to occur and the inner layer 2a is thick. Begins to decrease.

  And degradation of bridge | crosslinking PE further advances with progress of use time, and the thickness of the inner layer 2a will be 0 in time B. On the other hand, the TPE constituting the outer layer 2b begins to deteriorate slightly before the point B where the thickness of the inner layer 2a becomes 0, and the hose bursts at time C.

  Here, in the hot water supply hot water hose according to the present invention, the anti-aging agent for the outer layer composed of the phenolic antioxidant and the phosphorus antioxidant is added in an amount of 0.1 to 3 wt% with respect to the thermoplastic elastomer. preferable. This is because, by setting the outer layer anti-aging agent to such an addition ratio, combined with the synergistic effect of the two oxidizing agents, the aging of the inner surface layer tube 2 is more effectively prevented.

  That is, when the anti-aging agent for the outer layer is added in an amount of less than 0.1 wt% with respect to the thermoplastic elastomer, it is impossible to effectively replenish the anti-aging agent to the inner layer 2a side and to prevent the outer layer 2b itself from aging. On the other hand, when the anti-aging agent for the outer layer is added in excess of 3 wt% with respect to the thermoplastic elastomer, poor dispersion may occur during molding, or the adhesion between the inner layer and the outer layer may deteriorate. There is.

As described above, the water supply and hot water supply hose according to the present invention includes the inner surface layer tube including at least an inner layer and an outer layer, and the water supply and hot water supply hose including the reinforcing layer formed around the outer layer of the inner surface layer tube. The inner layer of the layer tube is a crosslinked polyethylene resin having a thickness of 0.1 to 1.0 mm, the outer layer of the inner surface layer tube is a thermoplastic elastomer having rubber elasticity, and the degree of crosslinking of the soft segment of the thermoplastic elastomer Is 90% or more, it is possible to provide a long-life water and hot water supply hose that is remarkably excellent in flexibility, chlorine resistance and heat aging resistance.

<Example-A>
First, the water supply hot water supply hose which changed the thickness structure of the inner layer and outer layer which comprise an inner surface layer tube was made as an experiment, and the difference in these hose softness | flexibility was confirmed. The prototype inner surface layer tube was constructed such that the inner layer was made of crosslinked PE and the outer layer was made of a thermoplastic elastomer (specifically, TPO), and the total thickness of both was 1.2 mm. Then, a reinforcing layer made of nylon fiber and stainless steel wire was provided on the outer periphery of these inner surface layer tubes, and an outer surface resin layer was further formed thereon to form a prototype hose.

Such a prototype hose is cut into a length of 295 mm to obtain a test hose. One end of the test hose is bent into a U shape at a speed of 5 mm / sec, and the bending torque is measured with a torque meter. The bending torque when the radius reached 60 mm was defined as the rigidity of the hose. Table 3 shows the measurement results of stiffness for each inner layer structure.
FIG. 5 shows the relationship between the rigidity and the cross-linked PE thickness. As can be seen from FIG. 5, when the cross-linked PE thickness exceeds 1.0 mm, the rigidity increases rapidly. Therefore, the upper limit of the inner layer thickness constituting the inner surface layer tube is preferably 1.0 mm.

<Example-B>
Next, the effect of the degree of cross-linking of the thermoplastic elastomer soft segment constituting the outer layer of the inner surface layer tube on the life of the hot and cold water supply hose was examined. As shown in Table 4, three types of inner layer tubes having the same configuration and having different cross-linking degrees of the soft segment (EPDM) were manufactured using TPO as the thermoplastic elastomer constituting the outer layer of the inner layer tube. However, an anti-aging agent is not added to the outer layer of the inner layer tube, but an ultraviolet absorber is added to the raw material of the inner layer.

  Then, in order to test the life of these hot water and hot water supply hoses at an accelerated rate, chemical water maintained at the following chemical water conditions is circulated through the trial inner surface layer tube at a water pressure of 0.3 kPa, and a crosslinked PE layer for the test time. Chlorine circulation test was conducted to measure the wall thickness change of the sample with a microscope.

  With reference to FIGS. 6 and 7, the results of a chlorine circulation test in which water is continuously passed under such conditions and the test time until the tube bursts will be described as the test life will be described below. FIG. 6 shows the results of a chlorine circulation test of the inner layer tube having different degrees of crosslinking of the thermoplastic elastomer soft segment (EPDM), and FIG. 7 shows the relationship between the degree of crosslinking of the thermoplastic elastomer soft segment (EPDM) and the test life. is there. In addition, it is known from the actual life of products with market results that the test time of 800 [h] in this chlorine circulation test corresponds to an actual life of 5 years.

Chemical water conditions / chemical water temperature: 80 ° C
・ Residual chlorine concentration: 50ppm
・ Copper ion concentration: 0.6ppm
・ PH: 6.6

  As shown in FIG. 7, the test life tends to increase rapidly when the degree of cross-linking of the thermoplastic elastomer soft segment (EPDM) is 90% or more. It is preferable that the degree of crosslinking is 90% or more.

<Example-C>
Therefore, next, the inner layer and the outer layer constituting the inner layer tube having a total thickness of 1.2 mm are changed, and the inner layer is a cross-linked PE having four types of thicknesses ranging from 0.2 to 1.0 mm, As shown in Table 5, an inner layer tube shown in Table 5 was manufactured so that the degree of crosslinking of EPDM, which is a soft segment of TPO, was 95%. However, an anti-aging agent is not added to the outer layer of the inner layer tube, but an ultraviolet absorber is added to the raw material of the inner layer.

  FIG. 8 shows the result of a chlorine circulation test that was exactly the same as that described in Example-B, using these prototype inner surface layer tubes. FIG. 8 is a diagram showing changes in the thickness of the inner surface layer made of crosslinked PE by a chlorine circulation test. Examples-10 and -11 where the thickness of the crosslinked PE is thin have already been ruptured, but Examples-12 and -13 where the thickness of the crosslinked PE is thick are still in the middle of the test stage where the rupture has not yet occurred.

  From the results of Example-C, it can be seen that the factor that determines the life of the hot and cold water supply hose according to the present invention is dominated by the inner layer thickness constituting the inner layer tube, that is, the cross-linked PE thickness. Further, in Examples -12 and -13, the test time reached 10000 [h], and as described above, the test time 800 [h] corresponds to an actual life of 5 years. [H] × (5 [years] / 800 [h]) = 62.5 [years] The long life expected is reached.

<Example-D>
As shown in Table 6, the outer layer is composed of two types of inner layer tubes having different thicknesses of the inner layer crosslinked PE and the outer layer thermoplastic elastomer (TPO) constituting the inner layer tube having a total thickness of 1.2 mm. A thermoplastic elastomer (TPO) added with 1.0% of an antioxidant comprising a phenolic antioxidant and a phosphoric acid antioxidant, and a thermoplastic elastomer (TPO) with no addition of this antioxidant, The soft segment (EPDM) was prototyped so that the degree of crosslinking was 95%.

  FIG. 9 shows the result of the same chlorine circulation test as that of Example-B described above, using the prototyped inner surface layer tube. FIG. 9 is a diagram showing a comparison of chlorine circulation test results according to whether or not an antioxidant is added to a thermoplastic elastomer (TPO) constituting the outer layer of the inner layer tube according to the embodiment of the present invention. It can be seen that the test life is extended by 20 to 30% by adding an antioxidant comprising a phenolic antioxidant and a phosphoric acid antioxidant to the thermoplastic elastomer (TPO) constituting the outer layer.

  In FIG. 9, Examples-14 to -16 have already ruptured and reached the test life, but in Example-17, the test time has reached 12000 [h] and is still continuing. The test time has reached a long life expected to be 12000 [h] × (5 [year] / 800 [h]) = 75 [year] at the present time, and the actual life of 50 years or more as a target of the present invention. Can be achieved.

As mentioned above, the hot water supply hot water hose according to the present invention is a crosslinked polyethylene resin in which the inner layer of the inner surface layer tube has a thickness of 0.1 to 1.0 mm, and the outer layer of the inner surface layer tube is a thermoplastic elastomer having rubber elasticity. At the same time, since the degree of cross-linking of the soft segment of this thermoplastic elastomer is 90% or more, it provides a long-life and flexible water supply and hot water supply hose with outstanding workability, chlorine resistance and heat aging resistance. obtain.

  Further, according to the hot water supply / hot water hose according to the present invention, the thermoplastic elastomer is made of a polyolefin-based thermoplastic elastomer, and the soft segment is ethylene propylene diene monomer (EPDM) rubber, so that the outer layer of the inner surface layer tube is high. Flexibility and bending fatigue resistance can be imparted.

It is a partially cutaway perspective view which describes the lamination structure of the water supply hot-water supply hose which concerns on embodiment of this invention. It is structure explanatory drawing which showed typically the structure of the dynamic bridge | crosslinking thermoplastic elastomer which concerns on embodiment of this invention. It is a typical explanatory view for explaining the effect which relates to the hot-water supply hot-water hose of the present invention, and uses an anti-aging agent different from the anti-aging agent for the inner layer as the anti-aging agent for the outer layer. It is a typical explanatory view for explaining a deterioration process of an inner surface layer tube with elapsed time concerning a hot water supply hot water hose of the present invention. It is a figure which concerns on the Example of this invention and shows the relationship of the rigid force with respect to bridge | crosslinking PE thickness. The chlorine circulation test result of the inner surface layer tube from which the crosslinking degree of the soft segment (EPDM) of a thermoplastic elastomer differs in the Example of this invention is shown. It is a figure which concerns on the Example of this invention and shows the relationship between the crosslinking degree of a soft segment (EPDM) of a thermoplastic elastomer, and a test lifetime. It is a figure which concerns on the Example of this invention and shows the thickness change by the chlorine circulation test from which the thickness of bridge | crosslinking PE inner surface layer differs. It is a figure which concerns on the Example of this invention and shows the comparison of the chlorine circulation test result by the presence or absence of the addition of an anti-aging agent to the thermoplastic elastomer (TPO) which comprises the outer layer of an inner surface layer tube. It is a partially notched perspective view of the hose which concerns on the prior art 2. FIG.

Explanation of symbols

1: Water supply hot water supply hose 2: Inner layer tube, 2a: Inner layer, 2b: Outer layer 3: Reinforcing layer, 3a: Inner fiber layer, 3b: Outer fiber layer 4: Outer resin layer 5: Dynamically cross-linked thermoplastic elastomer, 5a: PP matrix,
5b: EPDM rubber particles 6: Cross-linked PE whitening layer, 7: Crack

Claims (5)

In a hot and cold water supply hose comprising at least an inner surface layer tube composed of an inner layer and an outer layer and a reinforcing layer formed around the outer layer of the inner surface layer tube, the inner layer of the inner surface layer tube has a thickness of 0.1 to 1.0 mm. A water supply and hot water supply hose, characterized in that the outer layer of the inner layer tube is a thermoplastic elastomer having rubber elasticity, and the soft segment of the thermoplastic elastomer has a crosslinking degree of 90% or more.   The hot water and hot water supply hose according to claim 1, wherein the thermoplastic elastomer is made of a polyolefin-based thermoplastic elastomer, and the soft segment is ethylene-propylene-diene monomer rubber (EPDM). 3. The hot water and hot water supply hose according to claim 1, wherein the thermoplastic elastomer is a dynamically cross-linked thermoplastic elastomer in which a dispersed phase of EPDM particles dynamically cross-linked is formed on a polypropylene matrix.   The inner layer and the outer layer of the inner layer tube contain an anti-aging agent, and the thermoplastic elastomer constituting the outer layer includes an anti-aging agent (anti-aging agent for inner layer) contained in the cross-linked polyethylene resin constituting the inner layer; The water supply hot-water supply hose according to any one of claims 1 to 3, wherein a different anti-aging agent (anti-aging agent for outer layer) is used. The inner layer antioxidant is ultraviolet absorber, according to claim 4, wherein the outer layer antioxidant is characterized in that it is a antioxidant comprising a phenolic antioxidant and a phosphorus based antioxidant Water supply hot water hose.

Images