JPS6018684A - Flexible composite hose - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Background and Objects of the Invention The present invention provides a hose for transporting fluids, particularly a hose that has flexibility comparable to that of a rubber hose, and has solvent resistance comparable to that of a Plus Deck hose. This invention relates to a flexible composite bose for transporting paint.

As a flexible hose, N4A If necessary
A so-called rubber hose having an inner and outer two-layer structure made of vulcanized rubber with a reinforcing layer is well known. However, most general-purpose rubbers, including nitrile rubber and chloroprene rubber, swell significantly with the solvents contained in paints and have a large decrease in strength, so they are not suitable for transporting liquids containing solvents such as paints. is inappropriate and is not currently in use.

Although it has the problem of a unique odor, diocol rubber is an exceptional rubber that swells relatively little with solvents and exhibits little loss of strength, and hoses using this for the inner layer have been put into practical use.

However, if the solvent is aromatic such as 1 to luene or xylene, or thinner, even diokol rubber will swell and lose its strength considerably, and cracks will easily occur when bent or crushed during use.
In some cases, the inner layer of Dicol rubber may peel off from the outer layer, which may clog the spray gun that is the end-use device.

Known hose materials exhibiting excellent resistance to such solvents include nylon resins, aromatic polyester resins, and knot resins made of tetrafluoroethylene copolymers. However, all of these materials have extremely high rigidity, and when molded into a hose, they do not have the flexibility of a rubber hose, and to improve flexibility, reducing the hose wall thickness makes it easier to bend. It buckles.

In order to obtain both flexibility and solvent resistance as a hose,
A thin-walled tube is made using a resin that has good solvent resistance, such as tetrafluoroethylene/ethylene copolymer, and then it is glued to a thick-walled vulcanized rubber outer duplex. An integrated hose has been considered, but bonding between the resin and rubber requires adhesive treatment such as etching treatment using metallic sodium, which is likely to contaminate the working environment and is expensive. This increases the cost and is economically disadvantageous.

The object of the present invention is to provide a flexible composite hose that has excellent solvent resistance and flexibility comparable to rubber hoses, is resistant to buckling when bent, is relatively inexpensive, and is particularly suitable for transporting paint. The offer is to cover.

[Summary of the Invention] According to the present invention, a specific material is used as the inner layer tube, vulcanized rubber is used as the outer layer, and at least one fiber-reinforced layer is used as a boundary layer between the two, and the two are integrated. By appropriately selecting the thickness of the outer layer with respect to that of the inner layer, and by appropriately selecting the relationship between the inner hole radius of the inner layer duplex and the sum of the thicknesses of the two inner and outer layers, achieved.

Thermoplastic urethane elastomer is suitable as the material used for the inner layer, and this elastomer may be either an ester type or an ether type, but it is commonly used as a paint solvent. Dissolved in W?, chthons such as methyl ethyl lactone, aromatic solvents such as toluene, xylene, or mixed solvents thereof. Adipate-based ester or adipate-based ether types, which do not cause swelling and have a small swelling amount, are preferred.

As the outer layer rubber, natural rubber, any synthetic rubber, or a blend rubber of multiple synthetic rubbers can be used, but chloroprene rubber, hypalon rubber, dilene-propylene rubber, etc., which have excellent weather resistance, are suitable. .

The fibers forming the fiber reinforcing layer may be any natural fibers such as cotton yarn, synthetic fibers such as rayon, vinylon, nylon, Tealon, or aromatic polyamide. For example, if the outer layer is made of chloroprene rubber, it should be treated with an adhesion promoting treatment depending on the type of outer layer rubber, such as treated with a mixture of Resorcin-F-A lumaline and chloroprene latex. As for the compatibility V of the method, a known method can be used.

In order to achieve flexibility equivalent to that of a rubber hose, as well as strength against buckling, conditions are given to the wall thickness of each component depending on the hole diameter of the finished hose. Regarding flexibility, the wall thickness (h2) of the urethane tube that makes up the inner layer
It has been found that it is preferable to set the thickness to 1/2 or less of the thickness (h2) of the rubber constituting the outer layer.

This is a thermo-flexible urethane elastomer with excellent solvent resistance.
50 to 80), so if the wall thickness (HL) of the inner layer tube is larger than the above, the flexibility characteristics such as the minimum bending radius will be significantly lower than that of a rubber hose. be. More preferably, the thickness of the thick-walled tube (hl) is 1/3 or less of the thickness of the outer rubber layer (h2), and by covering it in this way, its flexibility can be made equivalent to that of a rubber hose.

It has been found that the best way to prevent buckling is to increase the ratio of the total hose wall thickness (bt+b2) to the radius (r) of the hose inner hole to 1/51:l. J, that is, the radius of the hose inner hole (
If the total wall thickness (bl+b2) is small compared to r), buckling is likely to occur even with a small amount of bending, whereas if it is large, it can withstand sufficient bending deformation.

On the other hand, when handling hoses, we have found that approximately 15
In order to achieve a minimum bending radius (R) that is more than twice as large without buckling, the total wall thickness (t)1+b 2 ) must be the radius of the hose inner hole ('r
) of 115 and above.

[Example] Hereinafter, the fact of J2 will be explained below using Example d3 and a comparative example.
Regarding r1, boce material, etc., C is merely an example, and the scope of the present invention is not limited thereto.

Example Tubes made of thermoplastic/cretan elastomer (manufactured by Inu Nippon Ink Co., Ltd., part name: T~5167) with various inner hole radii (r) and various types of holes were prepared, and resorcinf A lumaline was placed on top of the tubes. A 1200 denier vinyl 1'' system treated with a chloroprene radex mixture is used for reinforcement of 36 strands of braided wood with a so-called static angle of braid angle R3. Various thicknesses of rubber mixtures containing rubber as the main component and adjusted so that the rubber hardness after heating is 70 ± 5 according to JIS △ b2)
This was extruded and coated with a steam pressure of 3.8Kgf/cr.
Heat molding was performed using pressurized steam A for 45 minutes.

The cross-sectional structure of the resulting hose, as shown in Figure 1, consists of a thermoplastic/cretane elastomer inner layer 1, a chloroprene rubber outer layer 3d3, and a braided reinforcing layer 2 that joins them together.
It consisted of

Experiment 1 The minimum bending radius R of the composite bose obtained in Example just before buckling was measured. The results are shown in Table 1.

However, the Δ mark in Table 1 indicates a sample prepared with an outer layer thickness/inner layer thickness ratio outside the range of the present invention for comparison.

Table 1 As is clear from this experiment, if the ratio (R/2r) between the minimum bending radius R and the hose inner diameter 2r is 12.1 or more, it can withstand bending sufficiently, but the total wall thickness of the hose (
It can be seen that the hoses with external slopes 25 and 26 in which bl-+-1]2) was set to 115 or less of the inner hole radius had an extremely large [</2r ratio] and were easily buckled by bending.

The ease of bending the hose is determined by the inside diameter of the hose and the hose wall thickness J5 J
Although it depends on the elastic modulus of the material of the hose and the bonding force between the inner and outer layers and the braided reinforcing layer, in general, rubber hoses are easier to bend than plastic hoses, so it is also possible to increase the thickness of the rubber layer. The force required for bending may be relatively small, and it is relatively easy to obtain a highly flexible hose with a small minimum bending radius. In the present invention, ease of bending is realized by minimizing the thickness of the inner layer made of plastic, and the thickness of the outer layer is made sufficient (to obtain a material that is difficult to buckle).

Comparative Example 1 A thiocol rubber tube was extruded as an inner layer to a thickness of 3.5 mm on a nylon mandrel with a diameter of 19 mm, and a braided reinforcing layer and a rubber outer layer with a thickness of 3 mm were provided thereon in the same manner as in the example. A rubber hose having an outer diameter of 32 mm was prepared by vulcanization molding using pressurized steam and consisting of a thiokol rubber inner layer 4 J5 and a rubber outer layer 3 with a braided reinforcing layer 3 on the inside as shown in FIG.

Comparative Example 2 A hose shown in FIG. 3 with an inner diameter of 19 mm, an inner layer thickness of 1.5 mm, and an outer layer 3 thickness of 5 mm was obtained in the same manner as in the example except that the braided reinforcing layer was omitted. The peel adhesion between the inner layer 1 and the outer layer 3 immediately after molding was approximately 5 Kgf/25 mm.Experiment 2 As shown in Figure 4, the sample 11°1 had a length of 300 mm.
The bending rigidity of the hoses of 2.13.14 and Comparative Examples 1 and 2 was measured. That is, rollers 10 that rotate at their tips are fixed at intervals of 180 mm.
Apply the sample hose to the underside of the roller of the support column 12 that has a
The load required for the center part of the sample boce to lift 20 m from the bottom surface of the roller 10 by applying an upward force to the center part was regarded as the bending rigidity and was measured. The results are shown in Figure 5.

In Fig. 5, a3, reference numbers 12 to 14 correspond to sample numbers, and horizontal line A corresponds to the bending rigidity level of the hose of sample 11, J3J: and comparative example 1.
Point B is not in Table 1 +12/I) I = 6.0 and (b 1 + b 2 ) / l - 0,68' (showing data for the prepared hose according to the invention) be.

As is clear from this experiment, the bending load of a boce with a 1127bl value of 2 or less is 1.25 times or more than that of a rubber boce. This corresponds to raising the rubber hardness by 5 points. Similar experiments were conducted with hoses made of other materials with various inner diameters, and similar results were obtained. This experiment shows that good results cannot be obtained when b2/Ill is 2 or more.

Experiment 3 The ratio of toluene/methanol/ethyl acetate, which is a standard composition for paint thinner, was 70/15/15.
The mixture was sealed in the hoses of Materials II 11 to 14 of Examples of the present invention and Comparative Examples J and 2 and left at room temperature for 3 days. Thereafter, the thinner was removed, the C hose was bent 100 times, and the inside of the hose was observed.

The results are shown in Table 2.

Table 2 As is clear from the above Table 2, the inner layer of the small rubber according to the example of the present invention has poorer solvent resistance than thiokol rubber, and the adhesion to the outer layer is also reliable. This is because the inner layer is mechanically firmly fixed to the braided layer rather than directly to the rubber, which is difficult to adhere to, so that the thinner causes swelling and C can sufficiently withstand it.

Experiment 4 The inner tubes of the hose of the example of the present invention and the hose of the comparative example were taken out and immersed in thinner having the same composition as in Experiment 3, and left at room temperature for 3 hours.

Thereafter, the weight increase rate due to swelling and tear strength were measured. The results are shown in Table 3. In addition, the tear strength was measured using J
Based on IS B type.

Table 3 As is clear from Table 3, there is no significant difference in weight increase due to swelling in C, but the tear strength of the comparative example J5 Thiokol rubber deteriorates compared to the thermoplastic 1 cretan elastomer of the present invention. It turns out that this is remarkable.

The results of Experiment 3 are considered to be due to this mechanical and material difference.

[Effects of the Invention] As described above, the hose of the present invention uses 4J1 plastic material with poor solvent resistance for the inner layer, limits the total wall thickness of the hose and the inner layer thickness/outer layer thickness ratio, and uses a rubber bow. By ensuring unparalleled flexibility and mechanically fixing the inner periphery to the braided layer, it is possible to bond the inner and outer layers that can withstand swelling by solvents and repeated bending. .

As mentioned above, such hoses require a special adhesive treatment that poses problems in terms of working environment and pollution. f. It can be manufactured easily and inexpensively, and its industrial advantages are extremely large.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, FIGS.
The figures are diagrams showing comparative examples for comparison with the present invention.
The figure shows a method for measuring bending stiffness, and FIG. 5 shows the relationship between inner layer/outer layer thickness ratio and bending stiffness. 1: Thermoplastic urethane elastomer inner layer, 2: Braided reinforcement layer, 3: Vulcanized rubber outer layer, 4: Thiokol rubber inner layer, 10:
Laura, 12: Prop.

Claims (1)

[Claims] An inner layer tube made of thermoplastic urethane elastomer, an outer layer tube made of vulcanized rubber whose main component is scale rubber or a blend of two or more rubbers, and at least one layer of fiber reinforcement to mechanically connect these tubes. the outer layer dupe has a thickness twice or more that of the inner layer tube, and the inner hole radius of the inner layer tube is 115 or more of the sum of the thicknesses of the inner layer and outer layer tube. Flexible composite hose.