Polysiloxane rubber hose

Abstract

Provided is a polysiloxane rubber hose having excellent kink resistance and heat resistance, and good flexibility. The polysiloxane rubber hose (H1) is excellent in elasticity and is formed by winding a reinforcing material between an inner layer (1) and an outer layer (2), the polysiloxane rubber constituting the inner layer (1) has a durometer A hardness of 55-85, the polysiloxane rubber constituting the outer layer (2) has a durometer A hardness of 35-65, the polysiloxane rubber constituting the inner layer (1) or the outer layer (2) has a tear strength (Sa) of 5-60 N / mm as measured in accordance with JIS-K-6252, and the silicone rubber constituting the inner layer (1) or the outer layer (2) has a tensile strength (Sb) of 5-60 N / mm as measured in accordance with JIS-K-6252 as measured in accordance with JIS-K-6252 as measured in accordance with JIS-K-6252. The ratio of the viscoelastic recovery rate defined by formula (1) to the permanent strain rate defined by formula (2) (viscoelastic recovery rate / permanent strain rate) of the polysiloxane rubber constituting the outer layer (2) is 2.2 or more. Viscoelastic recovery rate = {(tensile deformation amount-stress residual deformation recovery amount-residual strain amount) / tensile deformation amount} * 100 (1) Permanent strain rate = (residual strain amount / tensile deformation amount) * 100 (2).

Description

Technical Field

[0001] The present invention relates to a polysiloxane rubber hose having excellent kink resistance and heat resistance and good flexibility, which is used in industries such as food, beverages, medical equipment, chemicals, or other industries, and more particularly, to a milking hose. Background Art

[0002] Tubes and hoses used in the medical field, food industry field, industrial parts field, etc. are required to have flexibility and kink resistance. In the past, tubes and hoses made of vinyl chloride resin were used. However, in recent years, due to increasing attention to environmental issues, tubes and hoses made of polysiloxane rubber have been developed to replace vinyl chloride resin (Patent Document 1).

[0003] In addition, since it is used for milking, a flexible milking hose is used in a milking device used in milking operations for collecting milk from a cow or the like. The milking hose is used between a teat attached to the udder of a cow or the like and a milking device body that generates suction to collect milk, or as a pipe inside the milking device body. When the milking hose is used between the teat and the milking device body, the milking hose is required to be flexible so as not to impose a burden on the udder while improving workability. In addition, the milking hose needs to be kink-resistant.

[0004] As milking hoses, representative hoses are known, such as tubes formed into thick walls by silicone rubber or the like, and tubes formed by soft resins. Such tubes are non-scaling cylindrical. For example, Patent Document 2 discloses a resin composition containing an amorphous α-olefin polymer and a petroleum resin, and a tube formed by the resin composition, and discloses that the tube has excellent kink resistance and heat resistance and can be used for milking purposes. In addition, Patent Document 3 discloses a multilayer tube, which is a layer composed of a linear low-density polyethylene resin with different moduli and a polyolefin elastomer layer, and the tube can suppress the dissolution of material components and is soft and can be used for milking purposes.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2010-54052 Patent Document 2: Japanese Patent Laid-Open No. 2004-285299

[0008] Patent Document 3: Japanese Patent Publication No. 2001-317662 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] In particular, from the perspective of milking, if the milking hose is heavy, not only will the operability during the milking operation be poor, but it will also put a burden on the udder of the cow, etc., so it is not preferred. That is, the milking hose is required to be lightweight. The tubular (non-scale cylindrical) milking hose described in the above patent document needs to have a relatively thick wall in order to prevent it from being tangled when bent, and it is difficult to achieve lightweight. In addition, in the attempt to automate the milking operation, if the milking hose is easily damaged, the milking operation cannot be carried out, which is likely to damage the health of the cow, etc., so the milking hose is required to have a long life.

[0011] In addition, in conventional silicone rubber reinforced hoses, if the silicone rubber of the inner and outer layers is softened for ease of use, when a tensile force is applied to the silicone rubber reinforced hose in the axial direction or when the hose as a whole expands due to changes in internal pressure, the inner and outer layers expand and contract in the axial direction. However, the material of the reinforcing material is significantly lower than the expansion rate of the silicone rubber, and the silicone rubber has high mold release and lubricity, so the reinforcing material is easy to move compared with other rubbers or constituent resins. Therefore, there is a problem that whenever the silicone rubber reinforced hose expands and contracts, the reinforcing material gradually moves from the axial end of the silicone rubber reinforced hose and falls off, and there is a problem that the pressure resistance performance of the fallen portion is significantly reduced.

[0012] Furthermore, in the connection structure of the silicone rubber reinforced hose, as the reinforcing material falls off, the pressure resistance of the connection end portion arranged at the axial end portion of the silicone rubber reinforced hose is significantly reduced. Therefore, due to the falling off of the reinforcing material, the connection end portion and the connection interface fitting are easily broken. In this case, the connection interface metal fitting must also be discarded together with the broken hose, so there is a problem that the hose replacement becomes expensive. Therefore, in order to prevent the reinforcing material from falling off, the following scheme can be considered, that is, by inserting the connection end portion of the reinforcing hose into the outer peripheral surface of the nipple and tightening it strongly from the outside with a fastener to reduce the diameter, thereby clamping the reinforcing material so that it does not move.

[0013] However, in this case, if the fastener is used to tighten strongly, the silicone rubber sandwiched between the fastener and the nipple will be squeezed out, and a layer will be formed between the inner surface of the nipple and the inner surface of the hose, so there is a problem that the fluid delivered to the hose remains on the generated layer or the resistance in the hose is increased. In addition, as a method of preventing the reinforcement material from falling off, it is conceivable to apply a silicone rubber primer on the surface of the reinforcement material to improve the adhesion between the inner layer and the outer layer, but there is a problem of increased cost.

[0014] The tubes or silicone rubber reinforced hoses of the prior art are not very satisfactory in terms of kink resistance and heat resistance. Under such circumstances, the problem to be solved by the present invention is to provide a hose that is excellent in kink resistance and heat resistance and has good flexibility. In particular, it is preferably a hose for milking. Furthermore, the reinforcing material is prevented from falling off, the torsional rigidity of the silicone rubber hose is increased to prevent the silicone rubber hose from being flattened due to torsion, and even if the silicone rubber hose is formed of silicone rubber with excellent flexibility, the disconnection of the hose connection end can be prevented with a simple structure.

[0015] Solutions to the problem

[0016] After repeated and intensive research, the inventors have found that the above-mentioned problems can be solved by the polysiloxane rubber hose of the present invention. The polysiloxane rubber hose of the present invention is a polysiloxane rubber hose made of polysiloxane rubber having excellent elasticity, wherein a reinforcing material is wound between the inner layer and the outer layer, the durometer A hardness of the polysiloxane rubber constituting the inner layer is 55 to 85, the durometer A hardness of the polysiloxane rubber constituting the outer layer is 35 to 65, at least one of the polysiloxane rubber constituting the inner layer or the polysiloxane rubber constituting the outer layer has a tear strength (S a) of 5 to 60 N / mm measured in accordance with JI SK-6252, and the ratio of the viscoelastic recovery rate defined by the following formula (1) to the permanent strain rate defined by the following formula (2) of the polysiloxane rubber constituting the outer layer (viscoelastic recovery rate / permanent strain rate) is 2.2 or more.

[0017] Viscoelastic recovery rate = {(tensile deformation - stress residual deformation recovery - residual strain) / tensile deformation} × 100 (1)

[0018] Permanent strain rate = (residual strain / tensile deformation) × 100···(2).

[0019] Effects of the Invention

[0020] According to the present invention, it is possible to provide a silicone rubber hose which is excellent in kink resistance and heat resistance and has good flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a partially cutaway front view of the silicone rubber hose according to the first embodiment of the present invention.

[0022] Figure 2 This is a partially cutaway front view of a silicone rubber hose according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0023] (Implementation Method 1)

[0024] Below, refer to Figure 1 Embodiment 1 of the present invention will be described. The silicone rubber hose H1 (see Figure 1 ), the durometer A hardness of the polysiloxane rubber constituting the inner layer 1 is 55 to 85, the durometer A hardness of the polysiloxane rubber constituting the outer layer 2 is 35 to 65, and at least one of the polysiloxane rubber constituting the inner layer 1 or the polysiloxane rubber constituting the outer layer 2 has a tear strength (S a) of 5 to 60 N / mm as measured in accordance with JI SK-6252, and is made of a polysiloxane rubber having excellent elasticity. The durometer A hardness of the polysiloxane rubber is measured in accordance with JI SK-6253 after the kneaded polysiloxane rubber before curing is cured at 200° C. for 2 hours.

[0025] By setting the hardness of the polysiloxane rubber to this range, the kink resistance can be improved, and the flexibility will not be too poor. When the lower limit value of the durometer A hardness of the polysiloxane rubber constituting the inner layer 1 is less than 55, the kink resistance is reduced, and when the upper limit value of the durometer A hardness of the polysiloxane rubber constituting the outer layer 2 is greater than 65, the required bending load becomes large, and a soft polysiloxane rubber hose H1 cannot be achieved in any case. In addition, when the lower limit value of the durometer A hardness of the polysiloxane rubber constituting the outer layer 2 is less than 35, the flexibility is good, but it is easy to kink, and when the upper limit value of the durometer A hardness of the polysiloxane rubber constituting the inner layer 1 exceeds 85, the hardness increases, and the convenience of use is poor like a metal flexible pipe.

[0026] In addition, the ratio of the viscoelastic recovery rate defined by the following formula (1) to the permanent strain rate defined by the following formula (2) of the polysiloxane rubber constituting the outer layer 2 of the polysiloxane rubber hose H1 of the present embodiment (viscoelastic recovery rate / permanent strain rate) is 2.2 or more, preferably 2.25 or more, more preferably 2.3 or more, and further preferably 2.5 or more. If this value is too low, the kink resistance of the polysiloxane rubber may be deteriorated.

[0027] Viscoelastic recovery rate = {(tensile deformation - stress residual deformation recovery - residual strain) / tensile deformation} × 100 (1)

[0028] Permanent strain rate = (residual strain / tensile deformation) × 100···(2).

[0029] In addition, as an embodiment of the polysiloxane rubber hose H1 of the present embodiment, when it is firmly tightened by a fastener and reduced in diameter, it is connected to a joint. However, in the case where the ratio of the viscoelastic recovery rate defined by the following formula (1) to the permanent strain rate defined by the following formula (2) is too low, when connected to the joint as above, since the force of the polysiloxane rubber to recover from deformation is weak, the fixing force of the reinforcing material is poor, and the reinforcing material may fall off.

[0030] In the above formulas (1) and (2), the tensile deformation, stress residual deformation recovery and residual strain are values ​​obtained based on the elastic hysteresis test of the resin composition. The tensile deformation represents the deformation length of the polysiloxane rubber when the polysiloxane rubber is stretched to a specified length (state a), the stress residual deformation recovery represents the change in the deformation length of the polysiloxane rubber from state a to state b when the tensile load is gradually reduced from state a and becomes zero (state b), and the residual strain represents the deformation length of the polysiloxane rubber when the polysiloxane rubber is left to stand in a free state for a certain period of time after state b (state c).

[0031] The elastic hysteresis test of the silicone rubber was carried out by the following method.

[0032] (1) Press molding at 160°C before curing After kneading the silicone rubber before curing at 200°C for 2 hours, a sheet with a thickness of 0.5 mm was prepared.

[0033] (2) A dumbbell-shaped No. 1 test piece (distance between marking lines = 40 mm) was prepared using the sheet in accordance with JI SK-6251.

[0034] (3) The following operations (i) to (iv) were performed on the test piece at a temperature of 23° C. using a tensile testing machine (STROGR AP HR manufactured by Toyo Seiki Seisaku-sho, Ltd.).

[0035] (4) (i) The test piece is stretched at a crosshead speed of 500 mm / min to a stretching deformation rate of 100% (distance between marking lines 80 mm). (Stretching deformation = 40 mm)

[0036] (5) (ii) Immediately after stretching, the test piece is shrunk at a crosshead speed of 500 mm / min until the tensile stress becomes zero.

[0037] (6)(iii) Measure the distance between the marking lines when the tensile stress is zero, and find the difference between this distance and the distance between the marking lines of 80 mm when the tensile strain rate is 100%, and use this value as the stress residual strain recovery amount.

[0038] (7) (iv) The test piece with zero tensile stress is immediately left at 23°C in a free state for 5 minutes after the tensile stress becomes zero, and the distance between the marking lines is measured. The difference between the distance and the distance between the marking lines before the test, 40 mm, is calculated and the value is taken as the residual strain.

[0039] The silicone rubber hose H1 of the present embodiment is excellent in heat resistance and kink resistance and can be used for various molded products.

[0040] In addition, the polysiloxane rubber used in the inner layer 1 or the outer layer 2 for manufacturing the polysiloxane rubber hose H1 of the present embodiment has a tear strength (measured in accordance with JI SK-6252) of 5 to 60 N / mm, preferably 15 to 60 N / mm, after the pre-curing kneaded polysiloxane rubber is press-formed at 160°C and then cured for 2 hours at 200°C. If the tear strength is less than 5 N / mm, the deformation will not be restored when the hose is bent or stretched, causing dimensional deviation, thereby causing a change in wall thickness or difficulty in handling, and there is also a concern that the hose may crack starting from a portion where the wall thickness changes, so it is not preferable. Furthermore, if it is greater than 60 N / mm, the hose may be difficult to deform and handle, or the rebound elasticity when bent and used is large, which reduces the workability, so it is not preferable.

[0041] In addition, the polysiloxane rubber used to manufacture the polysiloxane rubber hose H1 of the present embodiment satisfies the following formula (3), and thus the flexibility and kink resistance become more excellent. Since the durometer A hardness of the polysiloxane rubber constituting the inner layer 1 is greater than the durometer A hardness of the polysiloxane rubber constituting the outer layer 2, when the polysiloxane rubber hose H1 is bent and used, the inner layer 1 having a relatively large hardness maintains the shape of the polysiloxane rubber hose H1, while the outer layer 2 having a low hardness deforms flexibly, thereby improving the flexibility and kink resistance of the polysiloxane rubber hose H1. Preferably, the durometer A hardness of the polysiloxane rubber constituting the inner layer 1 is greater than the durometer A hardness of the polysiloxane rubber constituting the outer layer 2 by 10 or more, and more preferably greater than the durometer A hardness of the polysiloxane rubber constituting the outer layer 2 by 15 or more.

[0042] Durometer A hardness of the polysiloxane rubber constituting the inner layer - Durometer A hardness of the polysiloxane rubber constituting the outer layer ≥ 10…(3)

[0043] In the polysiloxane rubber hose H1 of this embodiment, as the inner layer 1 and the outer layer 2 made of polysiloxane rubber satisfying a specific range of physical properties expand and contract in the axial direction of the hose, the braid (reinforcement material) 3 woven into a cylindrical shape also expands and contracts in the same direction. Furthermore, when the hose as a whole is twisted in the circumferential direction, the forces acting on the braided rows in the two intersecting directions are balanced, so that the hose can maintain a cylindrical shape.

[0044] like Figure 1As shown, the polysiloxane rubber hose H1 is integrated by weaving a braid 3 into a cylindrical shape between an inner layer 1 and an outer layer 2 and forming a layer. The inner layer 1 and the outer layer 2 are mainly made of polysiloxane rubber with excellent flexibility. The inner layer 1 is first extruded by a known extrusion molding device, and then the braid 3 described later is woven along its outer peripheral surface by a braiding machine (not shown), and then the outer layer 2 is extruded on the outside of the braid 3 and stacked.

[0045] The braided fabric 3 woven as above is a reinforcing yarn or reinforcing fiber such as polyester, nylon or aramid fiber, and a longitudinal braided row 3a extending in the axial direction of the silicone rubber hose H1 and a transverse braided row 3b extending in the circumferential direction of the silicone rubber hose H1 crossing the longitudinal braided row 3a and the transverse braided row 3b are woven in a flexible manner. The longitudinal braided row 3a and the transverse braided row 3b are woven in a direction such that the longitudinal braided row 3a is parallel to the axial direction of the silicone rubber hose H1, and the transverse braided row 3b is woven orthogonally to the axial direction of the silicone rubber hose H1, or as shown in FIG. Figure 1 As shown, the silicone rubber hose H1 is wound into a spiral shape at a predetermined angle to the axial direction, so that the forces acting on the longitudinal braided rows 3a and the transverse braided rows 3b are balanced with respect to the torsion of the silicone rubber hose H1. The crossing angle of these longitudinal braided rows 3a and transverse braided rows 3b can be appropriately tilted to any angle other than the substantially right angle shown in the figure.

[0046] In addition, the silicone rubber hose H1 of the present embodiment may be provided with other layers such as a third layer or a second reinforcement layer in addition to the inner layer 1, the outer layer 2, and the reinforcement layer composed of the braid 3. As a connection method for connecting the silicone rubber hose H1 to other equipment, it is conceivable to insert the connection end of the silicone rubber hose H1 into the outer peripheral surface of the threaded sleeve part, tighten it from the outside with a fastener such as a rivet tube or a hose clamp, a bag nut, or a split retainer to reduce the diameter, thereby holding the hose joint, etc., but the present invention is not limited to this. The joint can be made of hard synthetic resin or metal, etc., and by forming a threaded sleeve part on the axial front end side and providing a connection mechanism for connecting to other equipment on the base end side, it can be connected to other equipment in various uses.

[0047] Since the silicone rubber hose H1 of the present embodiment has the above-mentioned structure and features, when the inner layer 1 and the outer layer 2 of the silicone rubber hose H1 of the present embodiment act with tension in the axial direction of the silicone rubber hose H1 or when the hose as a whole expands due to changes in internal pressure, the viscoelastic recovery rate and permanent strain rate of the silicone rubber constituting the outer layer 2 of the silicone rubber hose H1 are within a predetermined range, so the silicone rubber has a strong force for recovering from deformation. As a result, the silicone rubber hose H1 is tightened by the fastener to reduce its diameter and firmly hold the reinforcing material, thereby preventing the reinforcing material from falling off.

[0048] Especially when the braided fabric 3 is used as a reinforcing material, Figure 1 As shown in the figure, since the braid 3 (reinforcement thread, reinforcement fiber) is braided by changing the direction alternately in the longitudinal direction and the transverse direction, it is possible to significantly prevent the thread from being derailed compared to a braid wound in a spiral shape. Furthermore, even if the polysiloxane rubber hose H1 is twisted in the circumferential direction as a whole, the force acting on the reinforcement material is balanced, and the polysiloxane rubber hose H1 can maintain its cylindrical shape. As a result, by improving the torsional rigidity of the polysiloxane rubber hose H1, it is possible to prevent the polysiloxane rubber hose H1 from being flattened due to twisting.

[0049] In addition, by reducing the diameter of the gasket while sandwiching it between the outer peripheral surface of the connection end of the silicone rubber hose H1 and the fastener, the fastener is protected from directly contacting the outer peripheral surface of the connection end. As a result, even a hose made of silicone rubber with excellent flexibility can prevent the connection end from breaking with a simple structure. The material of the gasket can be thermoplastic resin, rubber, metal, etc., and when used in food machinery or medical equipment, it is preferred to use hard or semi-hard silicone rubber, fluororesin, nylon resin, etc., which are safe in terms of food hygiene and excellent in heat resistance.

[0050] Other resins, rubber elastic components, additives, etc. may be added to the polysiloxane rubber of the present embodiment as needed. Examples of other resins include polyethylene resins such as high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene (LLDPE); ethylene copolymer resins such as ethylene-vinyl acetate copolymer resins, ethylene-acrylate copolymer resins, ethylene-methacrylate copolymer resins, and ethylene-styrene copolymer resins; homopolypropylene resins, block polypropylene resins, polybutene resins, poly-4-methyl-pentene-1 resins, polystyrene resins, polyester resins, polyamide resins, polyphenylene ether resins, polyacetal resins, and carbonate resins. Examples of the rubber elastomer component include: natural rubber; polybutadiene; liquid polybutadiene; polyacrylonitrile rubber; acrylonitrile-butadiene copolymer rubber; partially hydrogenated acrylonitrile-butadiene copolymer rubber; ethylene-propylene rubber, ethylene-butene rubber, ethylene-hexene rubber, ethylene-octene rubber and other ethylene rubbers having an ethylene unit content of 70 mol % or more; fluororubber; polyurethane rubber; isobutylene-isoprene copolymer rubber; non-crosslinked olefin thermoplastic elastomers, partially crosslinked olefin thermoplastic elastomers, and fully crosslinked olefin thermoplastic elastomers.

[0051] Examples of additives include antioxidants, antioxidants, antiozonants, stabilizers such as ultraviolet absorbers and light stabilizers, lubricants, fillers, flame retardants, high-frequency processing aids, antistatic agents, internal release agents, colorants, dispersants, anti-blocking agents, anti-fogging agents, and the like.

[0052] Examples of the lubricant include wax, higher alcohols, fatty acids, fatty acid metal salts, fatty acid amides, carboxylic acid esters, phosphoric acid esters, sulfonic acid metal salts, acid ester metal salts, acrylic resins, fluorine-containing resins, and silicones. Two or more of these may be used in combination.

[0053] Examples of the wax include petroleum waxes such as paraffin wax and microcrystalline wax; plant waxes such as rice bran wax; mineral waxes such as montan wax; and synthetic waxes such as polyethylene wax and low-molecular-weight polypropylene.

[0054] Examples of the higher alcohol include lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, behenyl alcohol, oleyl alcohol, erucyl alcohol, and 12-hydroxystearyl alcohol.

[0055] Examples of the fatty acid include lauric acid, palmitic acid, stearic acid, behenic acid, oleic acid, erucic acid, linoleic acid, and ricinoleic acid.

[0056] Examples of the fatty acid metal salts include salts of metals such as Li, Na, Mg, Al, K, Ca, Zn, Ba and Pb of fatty acids such as lauric acid, palmitic acid, stearic acid, behenic acid, oleic acid, erucic acid, linoleic acid and ricinoleic acid. Specific examples of fatty acid metal salts include lithium stearate, sodium stearate, calcium stearate and zinc stearate.

[0057] Examples of the fatty amide include lauryl amide, palmitamide, stearyl amide, oleic acid amide, erucic acid amide, methylene bisstearic acid amide, ethylene bisstearic acid amide, ethylene bisoleic acid amide, and stearyl diethanolamide.

[0058] Examples of the carboxylic acid esters include esters of carboxylic acids such as aliphatic carboxylic acids (acrylic acid, crotonic acid, isocrotonic acid, fumaric acid, maleic acid, succinic acid, aconitic acid, etc.), fatty acids (lauric acid, palmitic acid, stearic acid, behenic acid, oleic acid, erucic acid, linoleic acid, ricinoleic acid, etc.), hydroxycarboxylic acids (lactic acid, malic acid, tartaric acid, citric acid, etc.), aliphatic alcohols (myristyl alcohol, palmityl alcohol, stearyl alcohol, behenyl alcohol, 12-hydroxystearyl alcohol, etc.), aromatic alcohols (benzyl alcohol, β-phenylethanol, o-phthalic acid, etc.), polyols (glycerol, diglycerol, polyglycerol, sorbitan, sorbitol, propylene glycol, polypropylene glycol, polyethylene glycol, pentaerythritol, trimethylolpropane, etc.). Specific examples of the carboxylic acid esters include glycerol monooleate, glycerol dioleate, polyethylene glycol monostearate, and citric acid distearate.

[0059] Examples of the phosphoric acid ester include monoalkyl esters, dialkyl esters, and trialkyl esters of phosphoric acid and higher alcohols.

[0060] Examples of the acrylic resin include polymers having as main units structural units derived from acrylic acid esters such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and structural units derived from methacrylic acid esters such as methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. Specific examples of the acrylic resin include acrylic resins with the trade name of methylbutene manufactured by Mitsubishi Chemical Corporation, and acrylic resins with the trade name of KANEACE manufactured by KANEKA Corporation.

[0061] Examples of the sulfonic acid metal salts include sodium stearyl sulfonate, sodium lauryl sulfonate, sodium dodecylbenzene sulfonate, sodium dodecylnaphthalene sulfonate, potassium stearyl sulfonate, potassium lauryl sulfonate, dibutyl sodium sulfosuccinate, di-2-ethylhexyl sodium sulfosuccinate, di-sodium lauryl sulfosuccinate, and polyoxyethylene lauryl-2-sodium sulfosuccinate.

[0062] Examples of the acid ester metal salt include sulfuric acid ester salts such as sodium lauryl sulfate and potassium lauryl sulfate; and phosphoric acid ester salts such as sodium lauryl phosphate and potassium lauryl phosphate.

[0063] Examples of the fluorine-containing resins include polymers having as main units structural units derived from fluorine-containing olefins such as tetrafluoroethylene, hexafluoropropylene, fluoroalkylethylene and perfluoroalkyl vinyl ether; fluorine-containing alkyl acrylates such as perfluoroalkylene acrylate and perfluoromethylalkylene acrylate; and fluorine-containing compounds such as fluoroalkyl methacrylate. Specific examples of the fluorine-containing resins include polytetrafluoroethylene and perfluoro(polyoxypropylene ethyl ether).

[0064] The polysiloxane rubber hose H1 of this embodiment can be used as piping for oil, various chemicals, air, various gases, water, etc. in the fields of various industrial vehicles such as automobiles, construction machinery vehicles, agricultural machinery vehicles, and railway vehicles; various industrial and mining machinery such as machine tools, engineering machinery, agricultural machinery, mining machinery, industrial robots, chemical equipment sets, coating machines, pharmaceutical delivery machinery, food industry machinery, hydraulic tools, and ships.

[0065] Specific examples of the polysiloxane rubber hose H1 of the present embodiment include: a filling hose, an evaporative hose, a fuel hose, a vapor exhaust hose, a hose for fuel in a tank, a power steering hose, an air conditioning hose, a radiator hose, a heater hose, a transmission oil cooler hose, an engine oil cooler hose, a brake hose, a turbocharger drain hose, a fuel injection hose, an air conditioning hose, an air duct hose, an air intake hose, a vacuum control hose, an air pollution control hose, and other automotive hoses; a hose for hydraulic machinery, a hose for pneumatic machinery, a hose for centralized lubrication equipment, a hose for coating equipment, a hose for chemical plants, a hose for transferring solvents and liquids, a hose for transferring various liquefied gases, a hose for food-related machinery, a hose for beverage-related machinery, a hose for physical and chemical equipment, a hose for textile machinery, a hose for loading and unloading machinery, Printing machine hoses, transmission machine hoses, water treatment equipment hoses, fluid element hoses, industrial robot hoses, industrial vehicle hoses, agricultural machine hoses, construction machine hoses, machine tool air hoses, injection molding machine hoses, labor-saving machine hoses, air tools such as air screwdrivers / hammers, operating hoses, air pressure / electric signal hoses, air pressure / signal hoses, equipment hoses that require heat resistance, high insulation, and high-frequency characteristics, spot welding equipment hoses, steam hoses, agricultural spray hoses, brewing hoses, diving hoses, beltless oil pipes, gas pipeline hoses, pneumatic brake hoses, gas station hoses, tank truck hoses, rotary hoses, fire extinguisher hoses, and other industrial machinery and industrial vehicle hoses; various infusion hoses, suction and exhaust hoses, and other medical equipment hoses, etc. Milking hoses are particularly preferred.

[0066] According to the polysiloxane rubber hose H1 involved in the present embodiment described above, the following effects can be obtained. That is, the polysiloxane rubber hose H1 of the present embodiment is tightened by a fastener to reduce the diameter of the polysiloxane rubber hose H1, thereby firmly holding the reinforcing material and preventing the reinforcing material from falling off. Therefore, compared with the existing products in which the reinforcing material is easy to fall off, the pressure resistance of the entire hose can be maintained high and rupture can be prevented, and compared with the products in which the adhesion with the inner layer and the outer layer is improved by applying a polysiloxane rubber primer on the surface of the reinforcing material, the manufacturing cost can be reduced.

[0067] Furthermore, when the hose is twisted in the circumferential direction, the force acting on the reinforcing material is balanced, the hose maintains its cylindrical shape, and the hose is prevented from being crushed due to twisting by increasing the rigidity of the hose against twisting. In addition, the durability against cleaning with chemicals during milking operations is high, and the service life is long. When used not only in milking but also in industries that use cleaning with chemicals, the product can be used as a product with a service life far exceeding that of conventional products.

[0068] (Implementation Method 2)

[0069] Next, refer to Figure 2 A second embodiment of the present invention will be described. A silicone rubber hose H2 (see Figure 2 ) The wire material 4 as a reinforcing material is wound into a spiral shape between the inner layer 1 and the outer layer 2 to form a coil shape, thereby integrating. The structure other than this is the same as that of the first embodiment, so the description is omitted.

[0070] The wire 4 is a metal wire that is not easy to rust, such as stainless steel, or a hard fiber such as a monofilament composed of a synthetic resin fiber, or a hard wire composed of a hard synthetic resin, and is formed by being guided from a coil forming machine or a coil storage part and wound toward the outer periphery of the inner layer in a stationary state.

[0071] In the silicone rubber hose H2 of the present embodiment, as the inner layer and the outer layer made of silicone rubber satisfying a specific range of physical properties expand and contract in the axial direction of the hose, the reinforcing material formed in a coil shape also expands and contracts in the same direction. Furthermore, when the entire hose is twisted in the circumferential direction, the repulsive force of the reinforcing material formed in a coil shape balances this, and the hose maintains a cylindrical shape.

[0072] As mentioned above, although each embodiment of the present invention has been described, the present invention is not limited to the above-mentioned each embodiment, and various changes can be made without departing from the gist of the present invention.

[0073] [Example]

[0074] The present invention will be described in further detail below with reference to Examples and Comparative Examples. In the Examples and Comparative Examples, the physical properties of the silicone rubber hose were measured by the following methods.

[0075] 1. Viscoelastic recovery rate / permanent strain rate

[0076] In the embodiments and comparative examples, the ratio of the viscoelastic recovery rate to the permanent deformation rate of the polysiloxane rubber constituting the polysiloxane rubber hose (viscoelastic recovery rate / permanent deformation rate) is obtained by calculating the tensile deformation, stress residual deformation recovery, and residual deformation through the following operations (i) to (iv), and the viscoelastic recovery rate and permanent deformation rate are calculated by the following formulas (1) and (2).

[0077] (i) The silicone rubber was press-formed at 160° C. and then cured in an environment of 200° C. for 2 hours to produce a sheet with a thickness of 0.5 mm.

[0078] (ii) A dumbbell-shaped No. 1 test piece (distance between marking lines = 40 mm) described in JI SK-6251 was prepared using the produced sheet.

[0079] (iii) The following operations were performed on the prepared test pieces using a tensile testing machine (STROGRAPHR manufactured by Toyo Seiki Seisaku-sho, Ltd.).

[0080] (a) The test piece was stretched at a crosshead speed of 500 mm / min until the tensile strain rate reached 100% (distance between marking lines = 80 mm) (tensile strain amount = 40 mm).

[0081] (b) After the test piece is stretched, it is immediately retracted at a crosshead speed of 500 mm / min until the tensile stress becomes zero.

[0082] (c) The distance between the markings when the tensile stress of the test piece is zero is measured, and the difference between the measured distance between the markings and the distance between the markings of 80 mm when the tensile strain rate is 100% is calculated, and this value is taken as the stress residual strain recovery amount.

[0083] (iv) After the tensile stress reaches zero, the test piece with the tensile stress of zero is immediately allowed to stand at 23°C in a free state for 5 minutes, and the distance between the markings is measured. The difference between the measured distance between the markings and the distance between the markings before the test, 40 mm, is calculated and this value is taken as the residual strain.

[0084] Viscoelastic recovery rate = {(tensile deformation - stress residual deformation recovery - residual strain) / tensile deformation} × 100 (1)

[0085] Permanent strain rate = (residual strain / tensile deformation) × 100 (2)

[0086] 2. Hardness

[0087] After the silicone rubber was kneaded before curing at 160°C, it was cured at 200°C for 2 hours to prepare a sheet with a thickness of 2 mm. The hardness (Dur oA) of the sheet was measured according to JI SK-6253.

[0088] 3. Kink resistance

[0089] The molded silicone rubber hose (inner diameter 25.4 mm, outer diameter 35.5 mm) was wound around a 50 mm cylinder in an atmosphere at 23° C. and evaluated based on the following criteria.

[0090] 4. Whether it falls off

[0091] A pressure-resistant nipple was inserted into one end of a molded silicone rubber hose (inner diameter 25.4 mm, outer diameter 35.5 mm) and tightened with a tie to close it. Air was then supplied to the inside of the hose from the other end. The state of the reinforcing material when the hose ruptured due to pressure from inside the hose was confirmed and evaluated based on the following criteria.

[0092] 5. Tear strength

[0093] The kneaded silicone rubber before curing was press-formed at 160°C, and then subjected to curing reaction at 200°C for 2 hours, and measured according to JI SK-6251.

[0094] (Measurement results)

[0095] The polysiloxane rubber hoses of Examples 1 to 6 and Comparative Examples 1 to 4 shown in Table 1 below were assembled into actual milking devices of multiple dairy farms (Dairy Farm A to Dairy Farm), and monitored and evaluated during daily milking operations. These milking hoses were loaned out for monitoring purposes, and their composition information was not disclosed. All of them were recovered after the monitoring period. In addition, the so-called "hardness" in Table 1 refers to the durometer A hardness. The so-called "hose characteristics" in Table 1 refer to the ratio of the viscoelastic recovery rate to the permanent strain rate (the above formula (1) / formula (2)).

[0096] Examples 1 to 6 are polysiloxane rubber hoses in which the "hardness" of the polysiloxane rubber constituting the inner layer is 60 to 81 and the "tear strength" is 10 to 35 N / mm, the "hardness" of the polysiloxane rubber constituting the outer layer is 38 to 63 and the "tear strength" is 34 to 56 N / mm, and the "hose characteristics" of the polysiloxane rubber hose are 2.2 to 2.8. In Comparative Example 1, the "tear strength" of the polysiloxane rubber constituting the inner layer is less than 5. In Comparative Example 2, the "hardness" of the polysiloxane rubber constituting the outer layer is less than 35, and the "hose characteristics" of the polysiloxane rubber hose is less than 2.2. In Comparative Example 3, the "hardness" of the polysiloxane rubber constituting the inner layer is less than 55.

[0097] In addition, regarding the "Reinforcement Method" in Table 1, "1" is a polysiloxane rubber hose manufactured by the reinforcement method shown in Embodiment 1, and "2" is a polysiloxane rubber hose manufactured by the reinforcement method shown in Embodiment 2. In addition, Comparative Example 4 is a polysiloxane rubber hose composed of a single layer of polysiloxane rubber and having no reinforcement material.

[0098]

Table 1

[0099]

[0100] According to the monitoring evaluation, the silicone rubber hoses of Examples 1 to 6 were evaluated as being lighter and easier to handle than conventional thick-walled hoses / tubular milking hoses in terms of flexibility and lightness, which are items related to the operability of the milking apparatus.

[0101] Table 2 below shows the evaluation results of the life of the silicone rubber hoses of Examples 1 to 6 and the silicone rubber hoses / tubes of Comparative Examples 1 to 4.

[0102] The "kink resistance" in Table 2 was evaluated based on the following criteria.

[0103] ○: The outer diameter of the hose wound around the cylinder is greater than 50% of the original outer diameter.

[0104] △: The outer diameter of the hose wound on the cylinder is greater than 30% and less than 50% of the original outer diameter.

[0105] ×: The outer diameter of the hose wound around the cylinder is less than 30% of the original outer diameter.

[0106] The judgment of "cleaning durability" (lifespan) in Table 2 is that the silicone rubber hose / tube used for the longest time of 4 months in the cheese farming farms of 10 monitoring points is judged as unusable and reaching the end of its life if part of the hose wall solidifies or deforms and affects the use, or the hose wall breaks and leaks, or the hose wall has obvious cracks, etc., and is evaluated as ×. If no cracks are found, it can be used as a hose, but it is felt that part of the hose has solidified or deformed, and it is evaluated as △. In addition, if such special phenomena are not found and it is the same as the initial hose, it is evaluated as ○. Of course, there are hoses that deteriorate before 4 months.

[0107] The judgment of "presence of falling off" in Table 2 was evaluated based on the following criteria.

[0108] ○: There is no movement at the ends of the reinforcement material.

[0109] △: The end of the reinforcing material moves and is located between the hose connection end and the fastening tie portion.

[0110] ×: The end of the reinforcing material moves and is located away from the fastening tie when viewed from the hose connection end.

[0111]

Table 2

[0112]

[0113] One polysiloxane rubber hose of each example, 60 in total, was monitored, and one polysiloxane rubber hose / tube of each comparative example, 40 in total, was monitored. One month after the start of monitoring, samples of the polysiloxane rubber hose / tube of the comparative example were evaluated as △ and samples that reached the end of their life and were evaluated as × in any of the evaluation items. On the other hand, samples of the polysiloxane rubber hose of each example were evaluated as △ after 4 months, and no samples were evaluated as × during the 4-month monitoring period.

[0114] As shown in Table 2, the polysiloxane rubber hoses of the examples have excellent kink resistance and long life compared to the hoses of Comparative Examples 1 to 4. In addition, the polysiloxane rubber hoses of the examples have no fall-off of reinforcing materials compared to the hose of Comparative Example 2, and are prevented from being broken, and can be used continuously in milking operations for a long time, and are highly economical.

[0115] When the silicone rubber hose of each embodiment is used as a milking hose, the deterioration is related to the use mode during the cleaning operation. The milking hose is frequently cleaned internally after use to prevent the generation of dirt and bacteria. In this internal cleaning operation, a high-temperature (60 to 80 degrees) cleaning liquid containing acid or alkali is used. In addition, in order to improve the cleaning efficiency, during the cleaning operation, the cleaning liquid is not only continuously added, but also the cleaning liquid is strongly and intermittently sent into the hose in a spraying manner together with air by using the negative pressure of the milking device. In addition, during this cleaning operation, the silicone rubber hose is in a bent posture. Therefore, the high-temperature cleaning liquid that flows strongly into the hose in a spraying manner does not collide with the hose wall much in the straight part of the silicone rubber hose, while on the other hand, the cleaning liquid collides violently with the inside of the hose wall in the curved part of the silicone rubber hose. As a result, the silicone rubber hose is severely exposed to the high-temperature cleaning liquid at a specific location. Therefore, when the silicone rubber hose is cleaned, the curved part is easily deteriorated.

[0116] Explanation of symbols

[0117] 1…Inner layer 2…Outer layer

[0118] 3… Braid 3a… Longitudinal braid row

[0119] 3b…horizontal braid row 4…wire

[0120] H1, H2…Polysilicone rubber hose

Claims

1. A polysiloxane rubber hose, which is made of polysiloxane rubber with excellent elasticity and has a reinforcing material wound between an inner layer and an outer layer. The durometer A hardness of the polysiloxane rubber constituting the inner layer is 55 to 85. The durometer A hardness of the polysiloxane rubber constituting the outer layer is 35 to 65, At least one of the polysiloxane rubber constituting the inner layer and the polysiloxane rubber constituting the outer layer has a tear strength (S a ) of 5 to 60 N / mm as measured in accordance with JIS-K-6252. The ratio of the viscoelastic recovery rate defined by the following formula (1) to the permanent strain rate defined by the following formula (2) of the polysiloxane rubber constituting the outer layer (viscoelastic recovery rate / permanent strain rate) is 2.2 or more, Viscoelastic recovery rate = {(tensile deformation - stress residual deformation recovery - residual strain) / tensile deformation} × 100 (1) Permanent strain rate = (residual strain / tensile deformation) × 100···(2).

2. The polysiloxane rubber hose according to claim 1, which satisfies the following formula (3): The durometer A hardness of the polysiloxane rubber constituting the inner layer - the durometer A hardness of the polysiloxane rubber constituting the outer layer is ≥ 10…(3).

3. The polysiloxane rubber hose according to claim 2, wherein: The inner layer made of silicone rubber extruded by an extrusion molding device, the reinforcing material formed into a layer by braiding into a cylindrical shape along the outer peripheral surface of the inner layer by a braiding machine, and the outer layer made of silicone rubber extruded to the outside of the reinforcing material are stacked, and the longitudinal braiding row of the braided reinforcing material is tilted at a specified angle from the axial direction of the silicone rubber hose and wound into a spiral shape, and the transverse braiding row is wound into a spiral shape orthogonal to the longitudinal braiding row.

4. The polysiloxane rubber hose according to claim 2, wherein: The inner layer made of silicone rubber extruded by an extrusion molding device, the reinforcing material formed into a coil shape by spirally winding along the outer peripheral surface of the inner layer, and the outer layer made of silicone rubber extruded outside the reinforcing material are stacked.

5. The silicone rubber hose according to any one of claims 1 to 4, which is used for milking.

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