Multilayer tubular shaped body

Abstract

Provided is a multilayer tubular molded body having high flexibility and being difficult to generate wrinkles on the inner face. The multilayer tubular molded body (1) has an inner layer (2), an outer layer (3), and an intermediate layer (4) provided between the inner layer (2) and the outer layer (3) and bonding the two. The inner layer (2) contains polyolefin as a main component, the outer layer (3) contains thermoplastic polyurethane as a main component, and the intermediate layer (4) contains adhesive polyolefin as a main component. The ratio of the sum of the thickness (T3) of the outer layer (3) and the thickness (T4) of the intermediate layer (4) to the thickness (TT) of the multilayer tubular molded body (1) is 0.7 to 0.92.

Description

Technical Field

[0001] This invention relates to a multilayer tubular molded body. Background Technology

[0002] Polyolefins possess excellent heat resistance, transparency, and hydrophobicity, and are difficult to absorb odors and colors, but they have poor flexibility and brittleness. Therefore, when polyolefins are used to mold thick-walled tubular bodies, their flexibility is compromised, making them prone to breakage. Even when molded into thin-walled tubular bodies, they are still easily broken.

[0003] On the other hand, although polyurethane has excellent heat resistance, flexibility and transparency, it is prone to absorbing odors and colors, and has poor hydrophobicity.

[0004] Therefore, by combining polyolefins and polyurethanes to manufacture multilayer tubular molded bodies, it is possible to impart the properties of polyolefins, such as their resistance to odor and color adhesion and their excellent hydrophobicity, as well as the excellent flexibility of polyurethanes.

[0005] This multilayer tubular molded body can have a heat resistance temperature (80 to 100°C) that falls between that of a tubular molded body made of soft vinyl chloride (heat resistance temperature: 70°C) and a tubular molded body made of silicone (heat resistance temperature: 150°C). Therefore, in industries such as food or cosmetics, this multilayer tubular molded body can be differentiated from the aforementioned tubular molded bodies made of soft vinyl chloride and silicone in terms of performance and cost, making it suitable for the desired application or environment, such as piping or mechanical assembly.

[0006] For example, Patent Document 1 discloses a multilayer tube, i.e., a multilayer tubular molded body, having: an inner layer formed of polyolefin resin, an outer layer formed of polyurethane resin, and an intermediate layer located between the inner layer and the outer layer and formed of adhesive polyolefin resin.

[0007] Existing technical documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2008-132659 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] While the multilayer tube in Patent Document 1 describes excellent flexibility, it does not describe the problem of temperature dependence. Through the exploration of the inventors, it has been found that depending on the temperature of the fluid passing through and the thickness of the inner layer, wrinkles will form on the inner surface, making it unusable at the temperature of the aforementioned intermediate region.

[0011] Furthermore, the inventors have discovered that even at room temperature, wrinkles can easily form on the inner surface of the multilayer tube due to the degree of bending.

[0012] The purpose of this invention is to provide a multi-layered tubular molded body with high flexibility and low wrinkle formation on the inner surface.

[0013] Problem Solving Methods

[0014] The above-mentioned objectives can be achieved by the present invention described in (1) to (20) below.

[0015] (1) A multilayer tubular molded body, comprising: an inner layer, an outer layer, and an intermediate layer disposed between the inner layer and the outer layer and bonding the two together, characterized in that,

[0016] The inner layer contains polyolefin as the main component;

[0017] The outer layer contains thermoplastic polyurethane as the main component;

[0018] The intermediate layer contains adhesive polyolefin as its main component;

[0019] The sum of the thickness of the outer layer and the thickness of the intermediate layer is in a ratio of 0.7 to 0.92 to the thickness of the multilayer tubular body.

[0020] (2) The multilayer tubular molded body as described in (1) above, wherein the thickness of the intermediate layer is 0.1 or more and less than 2 relative to the thickness of the inner layer.

[0021] (3) The multilayer tubular molded body as described in (1) or (2) above, wherein the thickness of the inner layer is in proportion to the thickness of the multilayer tubular molded body from 0.06 to 0.25.

[0022] (4) The multilayer tubular molded body as described in any one of (1) to (3) above, wherein the content of the polyolefin in the inner layer is 75% by mass or more.

[0023] (5) A multilayer tubular molded body as described in any one of (1) to (4) above, wherein the softening temperature of the polyolefin is 95 to 190°C.

[0024] (6) A multilayer tubular molded body as described in any one of (1) to (5) above, wherein the polyolefin comprises at least one of polyethylene, syndiotactic polypropylene, isotactic polyprolene and polymethylpentene.

[0025] (7) A multilayer tubular molded body as described in any one of (1) to (6) above, wherein the thickness of the inner layer is 0.05 to 2.5 mm.

[0026] (8) The multilayer tubular molded body as described in any one of (1) to (7) above, wherein the content of the thermoplastic polyurethane in the outer layer is 75% by weight or more.

[0027] (9) A multilayer tubular molded body as described in any one of (1) to (8) above, wherein the softening temperature of the thermoplastic polyurethane is 135 to 200°C.

[0028] (10) The multilayer tubular molded body as described in any one of (1) to (9) above, wherein the thermoplastic polyurethane comprises at least one of adipate-based thermoplastic polyurethane, ether-based thermoplastic polyurethane, caprolactone-based thermoplastic polyurethane and polycarbonate-based thermoplastic polyurethane.

[0029] (11) A multilayer tubular molded body as described in any of (1) to (10) above, wherein the thickness of the outer layer is 0.5 to 2.5 mm.

[0030] (12) The multilayer tubular molded body as described in any one of (1) to (11) above, wherein the content of the adhesive polyolefin in the intermediate layer is 75% by mass or more.

[0031] (13) The multilayer tubular molded body as described in any one of (1) to (12) above, wherein the softening temperature of the adhesive polyolefin is 120 to 185°C.

[0032] (14) A multilayer tubular molded body as described in any of (1) to (13) above, wherein the adhesive polyolefin comprises a polyolefin having an aromatic ring in the side chain.

[0033] (15) The multilayer tubular molded body as described in (14) above, wherein the adhesive polyolefin comprises styrene-grafted polyolefin and polystyrene.

[0034] (16) A multilayer tubular molded body as described in any of (1) to (13) above, wherein the adhesive polyolefin comprises ester-containing groups in its side chains.

[0035] (17) The multilayer tubular molded body as described in (16) above, wherein the adhesive polyolefin comprises maleic anhydride-modified ethylene-vinyl acetate copolymer.

[0036] (18) A multilayer tubular molded body as described in any of (1) to (17) above, wherein the thickness of the intermediate layer is 0.01 to 1.5 mm.

[0037] (19) The multi-layer tubular molded body described in any of (1) to (18) above, wherein the maximum load in the compression bending test (span: 200 mm) of the multi-layer tubular molded body is 19 N or less.

[0038] (20) The multi-layer tubular molded body described in any of (1) to (19) above, wherein the deflection of the multi-layer tubular molded body in the deflection measurement test (temperature: 100°C) is less than 40 mm.

[0039] Invention Effects

[0040] According to the present invention, a multi-layered tubular molded body with high flexibility and low wrinkling on the inner surface can be obtained. Attached Figure Description

[0041] Figure 1 This is a partial perspective view showing an embodiment of the multilayer tubular molded body of the present invention.

[0042] Figure 2 It is along Figure 1 The cross-sectional view along line AA in the diagram.

[0043] Figure 3 This is a partial perspective view showing the structure of the pressure-resistant hose.

[0044] Figure 4 This is a diagram used to illustrate the method of compression bending test.

[0045] Figure 5 This is a diagram used to illustrate the method of measuring deflection. Detailed Implementation

[0046] Hereinafter, the multilayer tubular molded body of the present invention will be described in detail based on the preferred embodiments shown in the accompanying drawings.

[0047] <Multi-layer tubular molded body>

[0048] Figure 1 This is a partial perspective view illustrating an embodiment of the multilayer tubular molded body of the present invention. Figure 2 It is along Figure 1 The cross-sectional view along line AA in the diagram.

[0049] Figure 1 The multi-layer tubular molded body 1 shown has: an inner layer 2, an outer layer 3, and an intermediate layer 4 disposed between the inner layer 2 and the outer layer 3.

[0050] The structure of each layer will be explained in sequence below.

[0051] <<Inner Layer 2>>

[0052] The inner layer 2 is a layer mainly composed of polyolefin. Polyolefin has excellent heat resistance, transparency, and hydrophobicity, and is difficult to attract odors and colors. Therefore, by setting the inner layer 2 mainly composed of polyolefin, the multilayer tubular molded body 1 can be endowed with excellent properties based on these characteristics.

[0053] Examples of polyolefins include: low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ultra-low-density polyethylene (VLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ultra-high-density polyethylene (VHDPE), polypropylene such as isotactic polyprolene and syndiotactic polypropylene, polybutene, copolymers of ethylene and α-olefins, polymethylpentene, etc. These can be used alone or in combination of two or more.

[0054] The polyolefin preferably contains at least one selected from the group consisting of polyethylene, polypropylene, and polymethylpentene; more preferably, it contains at least one selected from the group consisting of LDPE, LLDPE, VLDPE, HDPE, VHDPE, isotactic polypropylene, syndiotactic polypropylene, and polymethylpentene; even more preferably, it contains at least one of HDPE, syndiotactic polypropylene, isotactic polypropylene, and polymethylpentene; and most preferably, it contains polypropylene. Using these polyolefins makes it easier to improve the heat resistance of the inner layer 2.

[0055] The softening temperature of polyolefins is preferably around 95 to 190°C, with 105 to 170°C being more desirable. By using polyolefins with this softening temperature, the multilayer tubular molded body 1 can be given a heat resistance temperature in the intermediate region between the tubular molded body made of soft vinyl chloride (heat resistance temperature: 70°C) and the tubular molded body made of silicone (heat resistance temperature: 150°C), namely 80°C to 100°C.

[0056] In addition, the softening temperature can be determined using the Dynamic Mechanical Analysis (DMA) method.

[0057] The polyolefin content in the inner layer 2 is preferably 75% by mass or more, more preferably 85% by mass or more, more preferably 95% by mass or more, and can also be 100% by mass. In this case, the inner layer 2 can be fully endowed with polyolefin-based properties.

[0058] <<Outer Layer 3>>

[0059] The outer layer 3 is a layer with thermoplastic polyurethane (TPU) as the main component. TPU has excellent heat resistance, flexibility, and transparency. Here, although the inner layer 2, which is mainly composed of polyolefin, tends to have reduced flexibility, by combining it with the outer layer 3, which is mainly composed of TPU, the overall high flexibility of the multilayer tubular molded body 1 can be ensured.

[0060] Examples of TPUs include adipate-based TPUs, ether-based TPUs, caprolactone-based TPUs, and polycarbonate-based TPUs. These can be used alone or in combination of two or more types.

[0061] In addition, adipate-based TPU is a general-purpose TPU, ether-based TPU is a TPU with excellent hydrolysis resistance and antibacterial properties, caprolactone-based TPU is a TPU with excellent injection molding properties, and polycarbonate-based TPU is a TPU with excellent hydrolysis resistance, antibacterial properties, and heat resistance.

[0062] The softening temperature of TPU is preferably around 135 to 200°C, and even more preferably around 155 to 190°C. By using TPU with this softening temperature, even when a fluid with a temperature of 80°C to 100°C flows through the multilayer tubular molded body 1, the deterioration and degradation of the outer layer 3 can still be better prevented or suppressed.

[0063] The weight-average molecular weight of TPU is preferably around 40,000 to 200,000, and even better around 80,000 to 160,000.

[0064] In addition, to the extent that the properties of the outer layer 3 are not compromised, various other polymers and additives, the same as those listed in the inner layer 2, may be added to the TPU.

[0065] The TPU content in the outer layer 3 is preferably 75% by mass or more, preferably 85% by mass or more, and even more preferably 95% by mass or more, and can also be 100% by mass. In this case, the TPU-based characteristics can be fully imparted to the inner layer 2.

[0066] Between the inner layer 2 and the outer layer 3, there is an intermediate layer 4, which is mainly composed of adhesive polyolefin. This intermediate layer 4 has the function of bonding the inner layer 2 and the outer layer 3. In addition, although the main function of the intermediate layer 4 is adhesive, the intermediate layer 4 can also perform other functions, such as: cushioning, kink resistance, gas permeability inhibition, ultraviolet protection, and heat resistance enhancement.

[0067] The adhesive polyolefin is preferably comprised of either a first polyolefin having an aromatic ring in the side chain or a second polyolefin having an ester-containing group in the side chain.

[0068] The aromatic rings of the first polyolefin have a large electron deviation and a portion with low electron density due to the presence of aliphatic hydrocarbon chains in the main chain, which constitutes a positively charged portion. On the other hand, the urethane bonds of the TPU have a negatively charged portion due to polarization. Therefore, the urethane bonds of the TPU are strongly attracted to the aromatic rings of the first polyolefin and stabilized by the van der Waals forces. That is, through the close interaction between the first polyolefin and the TPU, the outer layer 3 and the middle layer 4 are bonded together.

[0069] The second polyolefin contains adjacent C=O bonds, as well as CO or COC bonds, within its ester-containing groups. The C=O bonds have a higher electron density than the CO bonds, which strongly attracts the urethane bonds in the TPU, stabilizing them through van der Waals forces. That is, the close interaction between the second polyolefin and the TPU allows the outer layer 3 and the intermediate layer 4 to bond together.

[0070] On the other hand, since both the first and second polyolefins contain saturated hydrocarbon structures, i.e., polyolefins, in their main chains, they have a high affinity with the polyolefin of the inner layer 2. That is, through the close interaction between the first or second polyolefin and the polyolefin of the inner layer 2, the inner layer 2 and the intermediate layer 4 are bonded together.

[0071] Aromatic rings found in the first polyolefin can include, for example, benzene rings, naphthalene rings, allium rings, pyridine rings, and furan rings. Among these, benzene rings are preferred from the viewpoint of suppressing the decrease in affinity with the inner polyolefin.

[0072] Examples of the first polyolefin include styrene-grafted polyolefins and polystyrene.

[0073] The first polyolefin preferably contains styrene-grafted polyolefin and polystyrene. This first polyolefin allows for a closer interaction with the TPU. In addition, in this case, the first polyolefin may also be a mixture of styrene-grafted polyolefin and polystyrene (polymer alloy, etc.), or a core / shell structure having a polystyrene core and a styrene-grafted polyolefin shell.

[0074] Examples of ester-containing groups in the second polyolefin include: alkyl ester groups, aryl ester groups, maleic anhydride groups, succinic anhydride groups, phthalic anhydride groups, etc.

[0075] Examples of this second polyolefin include maleic anhydride-modified ethylene-vinyl acetate copolymer and maleic anhydride-modified polyvinyl alcohol. Preferably, the second polyolefin contains maleic anhydride-modified ethylene-vinyl acetate copolymer. This second polyolefin allows for a closer interaction with the polyolefin in the inner layer 2.

[0076] The amount of maleic anhydride added or grafted relative to the ethylene-vinyl acetate copolymer is preferably about 0.0001 to 15 parts by weight, and more preferably about 0.001 to 10 parts by weight, relative to 100 parts by weight of the ethylene-vinyl acetate copolymer.

[0077] The softening temperature of the adhesive polyolefin is preferably around 120 to 185°C, and more preferably around 140 to 165°C. By using an adhesive polyolefin with this softening temperature, even when a fluid at a temperature of 80°C to 100°C flows through the multilayer tubular molded body 1, the deterioration of the intermediate layer 4 can be suppressed and the peeling between the inner layer 2 and the outer layer 3 can be prevented.

[0078] The weight average molecular weight of adhesive polyolefins is preferably around 40,000 to 200,000, and more preferably around 80,000 to 160,000.

[0079] From the perspective of improving the adhesion and bonding properties of the intermediate layer 4, various tackifiers, i.e., adhesion enhancers, can also be added to the adhesive polyolefin.

[0080] Examples of tackifiers include: natural tackifiers such as rosin, rosin derivatives, terpene resins, and terpene derivatives; and synthetic tackifiers such as petroleum resins, styrene resins, benzofuran-indene resins, phenolic resins, and xylene resins.

[0081] In addition, within the range that does not impair the properties of the intermediate layer 4, various other copolymers and additives, the same as those listed in the inner layer 2, may be added to the adhesive polyolefin.

[0082] The content of adhesive polyolefin in the intermediate layer 4 is preferably 75% by mass or more, more preferably 85% by mass or more, more preferably 95% by mass or more, and can also be 100% by mass. In this case, the properties based on adhesive polyolefin can be fully imparted to the intermediate layer 4.

[0083] The present invention is characterized by appropriately setting the thickness of the inner layer 2, the thickness of the outer layer 3, the thickness of the intermediate layer 4, and their relationship. This feature will be described below.

[0084] The sum of the thickness T3 [mm] of the outer layer 3 and the thickness T4 [mm] of the middle layer 4 is in a ratio ([T3+T4] / TT) of 0.7 to 0.92 relative to the thickness TT [mm] of the multilayer tubular molded body 1. As a result, a multilayer tubular molded body 1 with high flexibility and low wrinkling on the inner surface can be obtained.

[0085] Multi-layered tubular moldings with poor flexibility are prone to breakage and cracking when forcibly deformed for piping, resulting in transport losses. Furthermore, delamination between the inner and outer layers can allow fluid to seep into the intermediate layers, leading to discoloration or bacterial growth. On the other hand, when wrinkles form on the inner surface of the multi-layered tubular molding 1 (hereinafter referred to as the "inner surface"), the lack of a smooth inner surface can easily cause fluid residue to stagnate, also contributing to bacterial growth.

[0086] The optimal ratio of [T3+T4] / TT is around 0.75 to 0.9, with 0.8 to 0.88 being particularly favorable. This will further enhance the aforementioned effects.

[0087] While the ratio (T4 / T2) of the thickness T4 of the intermediate layer 4 to the thickness T2 of the inner layer 2 is not specifically limited, it is preferable to be 0.1 or more but less than 2, preferably around 0.3 to 1.7, and even more preferably around 0.5 to 1.5. This prevents peeling between the inner layer 2 and the outer layer 3 while more reliably preventing wrinkles from forming on the inner surface.

[0088] Furthermore, while the ratio (T2 / TT) of the thickness T2 of the inner layer 2 to the thickness TT of the multilayer tubular molded body 1 is not particularly limited, it is preferably around 0.06 to 0.25, more preferably around 0.08 to 0.23, and even more preferably around 0.1 to 0.2. This prevents the thickness T2 of the inner layer 2 from increasing and easily prevents wrinkles from forming on the inner surface.

[0089] While there is no specific limitation on the exact value of the thickness T2 of the inner layer 2, it is preferably around 0.05 to 2.5 mm, and more preferably around 0.1 to 2 mm. This prevents the reduction of the flexibility of the multilayer tubular molded body 1 while making it difficult for wrinkles to form in the inner layer 2.

[0090] While there is no specific limitation on the exact value of the thickness T3 of the outer layer 3, it is preferable to be around 0.5 to 2.5 mm, better to be around 0.75 to 2 mm, and even better to be around 1 to 1.5 mm. This can significantly improve the flexibility of the multilayer tubular molded body 1.

[0091] Furthermore, while there is no particular limitation on the specific value of the thickness T4 of the intermediate layer 4, it is preferred to be around 0.01 to 1.5 mm, more preferably around 0.05 to 1 mm, and even more preferably around 0.1 to 0.5 mm. This allows for the prevention of excessive wall thickness in the multilayer tubular molded body 1 while maintaining high adhesion to the inner layer 2 and the outer layer 3.

[0092] For the multi-layer tubular molded body 1, the maximum load in the compression bending test (span: 200 mm) is preferably below 19 N, preferably below 17 N, and even more preferably below 14.6 N. A multi-layer tubular molded body 1 that meets these values ​​can be considered to have high flexibility. Furthermore, the lower limit of the maximum load is typically around 13 N.

[0093] Furthermore, in the flexural measurement test (temperature: 100℃), a flexural amount of less than 40 mm is preferred, less than 38 mm is even better, and less than 36 mm is even better. A multilayer tubular molded body 1 that meets these values ​​can be judged to have low temperature dependence and is unlikely to produce wrinkles in the inner layer 2. In addition, the lower limit of the flexural amount is usually around 30 mm.

[0094] Preferably, the multilayer tubular molded body 1 is formed by co-extrusion molding of the inner layer 2, the intermediate layer 4, and the outer layer 3 into a single unit. This multilayer tubular molded body 1 more easily improves the adhesion between the inner layer 2 and the outer layer 3 and the intermediate layer 4.

[0095] Furthermore, by using polyolefins, thermoplastic polyurethanes, and adhesive polyolefins with softening temperatures within the aforementioned range, stable and continuous co-extrusion molding can be achieved since their softening temperatures are similar to each other.

[0096] The multilayer tubular molded body 1 described above possesses sufficient flexibility, is difficult to wrinkle on its inner surface, and also exhibits excellent chemical resistance and heat resistance. Therefore, the multilayer tubular molded body 1 is suitable for applications such as food processing, cosmetics manufacturing, and chemical manufacturing.

[0097] The multi-layer tubular molded body of the present invention can be used, for example, as a pipe fitting, hose, etc.

[0098] Furthermore, the multi-layer tubular molded body of the present invention may also be provided with a reinforcing layer or an outermost layer formed of reinforcing wires, etc., as needed, thereby also serving as a pressure-resistant hose.

[0099] Figure 3 An example of this pressure-resistant hose is shown. Figure 3 This is a partial perspective view showing the structure of the pressure-resistant hose.

[0100] Figure 3 The pressure-resistant hose 10 shown has an inner layer 2, an outer layer 3 and a middle layer 4, and a reinforcing layer 5 and an outermost layer 6 are sequentially provided on the outside of the outer layer 3.

[0101] Examples of reinforcing wires constituting the reinforcing layer 5 include: multiple or single wires formed from polyester, nylon (registered trademark) or amide fibers, multifilaments formed from braided monofilaments, monofilaments formed from olefin resins, polyester resins, etc., flat yarns or ribbon yarns formed from ribbons, metal wires formed from stainless steel, etc., or coils formed from hard materials such as stainless steel.

[0102] The reinforcing wire is preferably formed into a mesh by winding it into a spiral shape along the outer layer 3, or by weaving it into a hollow cylindrical mesh along the outer layer 3. This improves the pressure resistance, shape retention, and other physical properties of the pressure-resistant hose 10.

[0103] Furthermore, as the material constituting the outermost layer 6, a resin material with good adhesion to the outer layer 3 is preferably used.

[0104] The multilayer tubular molded body of the present invention has been described above, but the present invention is not limited to the structure of the above embodiments.

[0105] The multilayer tubular molded body of the present invention can have other arbitrary structures added to the structure of the above embodiments, or can be replaced by any structure that performs the same function.

[0106] [Example 1]

[0107] The present invention will be described in detail below through embodiments, but the present invention is not limited thereto.

[0108] 1. Preparation of materials for each layer

[0109] 1-1. Materials for forming the inner layer

[0110] Prepare an inner layer forming material containing 100% by mass of syndiotactic polypropylene (manufactured by Nippon Polypropylene Co., Ltd., "WELNEX RMG02"). Furthermore, the softening temperature of polypropylene is 115°C.

[0111] 1-2. Materials for forming the outer layer

[0112] <Material 1 for outer layer formation>

[0113] Prepare an outer layer forming material containing 100% by weight thermoplastic polyurethane (manufactured by Daihatsu Seika Co., Ltd., "RESAMINEPH890"). Furthermore, the thermoplastic polyurethane has a weight-average molecular weight of 500 to 3,000 and a softening temperature of 183°C.

[0114] <Material 2 for outer layer formation>

[0115] Prepare an outer layer forming material containing 100% by weight of high-strength urethane rubber (manufactured by Bayer AG, "VULKOLLAN").

[0116] 1-3. Materials for forming the intermediate layer

[0117] <Material 1 for forming the intermediate layer>

[0118] A material for forming an intermediate layer containing 100% by mass of a binding polyolefin (manufactured by Mitsubishi Chemical Corporation, "MODIC GK110") is prepared. Furthermore, the binding polyolefin has a weight-average molecular weight of 5,000 to 110,000 and a softening temperature of 155°C or less.

[0119] <Material 2 for forming the intermediate layer>

[0120] A material for forming an intermediate layer containing 100% by mass of an adhesive polyolefin (manufactured by Mitsui Chemicals, Ltd., "ADMER NF528") is prepared. Furthermore, the adhesive polyolefin has a weight-average molecular weight of 50,000 to 110,000 and a softening temperature of 155°C or less.

[0121] 2. Manufacturing of multi-layered tubular molded bodies

[0122] (Example 1)

[0123] The inner layer forming material, the middle layer forming material 1, and the outer layer forming material 1 are melted and co-extruded using a three-layer extruder to manufacture a multi-layer tubular molded body with a three-layer structure.

[0124] In addition, the thickness of the inner layer is set to 0.2 mm, the thickness of the middle layer to 0.1 mm, the thickness of the outer layer to 1.3 mm, the inner diameter to 15 mm, and the outer diameter to 18.2 mm.

[0125] (Example 2)

[0126] Except for changing the thickness of the inner layer to 0.3 mm, the thickness of the middle layer to 0.3 mm, and the thickness of the outer layer to 1.0 mm, the other conditions are the same as in Example 1, and a multi-layer tubular molded body is manufactured.

[0127] (Example 3)

[0128] Except for changing the thickness of the inner layer to 0.3 mm, the thickness of the middle layer to 0.1 mm, and the thickness of the outer layer to 1.2 mm, the other conditions are the same as in Example 1, and a multi-layer tubular molded body is manufactured.

[0129] (Example 4)

[0130] Except for using intermediate layer forming material 2 instead of intermediate layer forming material 1, the other conditions are the same as in Example 1, and a multilayer tubular molded body is manufactured.

[0131] (Comparative Example 1)

[0132] Except for changing the thickness of the inner layer to 0.1 mm, the thickness of the middle layer to 0.1 mm, and the thickness of the outer layer to 1.4 mm, the other conditions are the same as in Example 1, and a multi-layer tubular molded body is manufactured.

[0133] (Comparative Example 2)

[0134] Except for changing the thickness of the inner layer to 0.1 mm, the thickness of the middle layer to 0.3 mm, and the thickness of the outer layer to 1.2 mm, the other conditions are the same as in Example 1, and a multi-layer tubular molded body is manufactured.

[0135] (Comparative Example 3)

[0136] Except for changing the thickness of the inner layer to 0.1 mm, the thickness of the middle layer to 0.2 mm, and the thickness of the outer layer to 1.3 mm, the other conditions are the same as in Example 1, and a multi-layer tubular molded body is manufactured.

[0137] (Comparative Example 4)

[0138] Except for using outer layer forming material 2 instead of outer layer forming material 1, the other conditions are the same as in Example 1, and a multilayer tubular molded body is manufactured.

[0139] 3. Assessment

[0140] 3-1. Softness

[0141] For the multilayer tubular molded bodies obtained in each embodiment and each comparative example, the maximum load in the compression bending test (span: 200 mm) was determined.

[0142] In addition, conduct such Figure 4 The compression-bending test shown.

[0143] Specifically, the multilayer tubular molded bodies obtained in each embodiment and comparative example were clamped between a pair of compression plates and bent into a U-shape at a compression speed of 200 mm / min. The maximum load was measured when the span reached 200 mm. Furthermore, the total length of the multilayer tubular molded body was assumed to be 400 mm.

[0144] The flexibility is assessed based on the measured maximum load and according to the following evaluation criteria.

[0145] ◎: Maximum load is 14.6N or less.

[0146] 〇: The maximum load is more than 14.6N and less than 19.0N.

[0147] ×: The maximum load exceeds 19.0N.

[0148] That is, it can be determined that the smaller the maximum load (N), the better the flexibility of the multilayer tubular molded body.

[0149] 3-2. The degree to which wrinkles easily due to heat

[0150] For the multilayer tubular molded articles obtained in each embodiment and each comparative example, the deflection was measured in a deflection measurement test (temperature: 100°C).

[0151] In addition, conduct such Figure 5 The test shown illustrates the measurement of deflection.

[0152] Specifically, the multilayer tubular molded bodies obtained in each embodiment and comparative example are prepared and maintained at 100°C for 30 minutes. Afterwards, a 200mm long metal rod is inserted and fixed so that a 30mm portion protrudes from the multilayer tubular molded body. Furthermore, the total length of the multilayer tubular molded body is assumed to be 400mm.

[0153] And, as Figure 5 As shown, with a 200mm portion protruding into the air, a 30mm protrusion of the metal rod was fixed to a fixed platform. Then, a load (100g) was applied to the end of the protruding portion for 1 minute, and its deflection (δ) was measured.

[0154] The degree to which the material is prone to wrinkling due to heat is assessed based on the measured deflection and the following evaluation criteria.

[0155] [Evaluation Benchmarks]

[0156] ◎: Deflection less than 36mm.

[0157] 〇: Deflection is 36mm or more but less than 40mm.

[0158] ×: The deflection is 40mm or more.

[0159] That is, it can be determined that the greater the deflection (mm), the higher the temperature dependence, and the easier it is to generate wrinkles on the inner surface of the multilayer tubular molded body.

[0160] These evaluation results are shown in Table 1 below.

[0161] [Table 1]

[0162]

[0163] As shown in Table 1, it can be confirmed that the multilayer tubular molded articles obtained by using each embodiment have high flexibility and are difficult to wrinkle on the inner surface.

[0164] In contrast, it can be confirmed that the multilayer tubular molded bodies obtained in each comparative example have poor flexibility and are prone to wrinkling on the inner surface.

[0165] Symbol Explanation

[0166] 1. Multilayer tubular molding body

[0167] 10 pressure-resistant hose

[0168] 2 Inner Layer

[0169] 3 outer layer

[0170] 4 intermediate layers

[0171] 5 reinforcement layers

[0172] 6 Outermost layer

Claims

1. A multi-layered tubular molded body, comprising: an inner layer, an outer layer, and an intermediate layer disposed between the inner layer and the outer layer and bonding the two together, characterized in that, The inner layer contains polyolefin as the main component; The outer layer contains thermoplastic polyurethane as the main component; The intermediate layer contains adhesive polyolefin as its main component. The outer layer has a thickness of 1.0 to 1.3 mm. The sum of the thickness of the outer layer and the thickness of the intermediate layer is in a ratio of 0.81 to 0.88 to the thickness of the multilayer tubular structure. The softening temperature of the polyolefin is 105 to 170°C. The softening temperature of the adhesive polyolefin is 140 to 165°C. The softening temperature of the thermoplastic polyurethane is 155 to 190°C.

2. The multilayer tubular molded body as described in claim 1, wherein, The thickness of the intermediate layer is greater than 0.1 and less than 2 relative to the thickness of the inner layer.

3. The multilayer tubular molded body as described in claim 1, wherein, The thickness of the inner layer is in the ratio of 0.06 to 0.25 to the thickness of the multilayer tubular body.

4. The multilayer tubular molded body as described in claim 1, wherein, The content of the polyolefin in the inner layer is 75% by mass or more.

5. The multilayer tubular molded body as described in claim 1, wherein, The polyolefin comprises at least one of high-density polyethylene, syndiotactic polypropylene, isotactic polypropylene, and polymethylpentene.

6. The multilayer tubular molded body as described in claim 1, wherein, The thickness of the inner layer is 0.05 to 2.5 mm.

7. The multilayer tubular molded body as described in claim 1, wherein, The content of the thermoplastic polyurethane in the outer layer is 75% by weight or more.

8. The multilayer tubular molded body as described in claim 1, wherein, The thermoplastic polyurethane includes at least one of adipate-based thermoplastic polyurethane, ether-based thermoplastic polyurethane, caprolactone-based thermoplastic polyurethane, and polycarbonate-based thermoplastic polyurethane.

9. The multilayer tubular molded body as described in claim 1, wherein, The content of the adhesive polyolefin in the intermediate layer is 75% by mass or more.

10. The multilayer tubular molded body as claimed in claim 1, wherein, The adhesive polyolefin comprises a polyolefin having an aromatic ring in its side chain.

11. The multilayer tubular molded body as claimed in claim 10, wherein, The adhesive polyolefin includes styrene-grafted polyolefin and polystyrene.

12. The multilayer tubular molded body as claimed in claim 1, wherein, The adhesive polyolefin contains ester-containing groups in its side chains.

13. The multilayer tubular molded body as claimed in claim 12, wherein, The adhesive polyolefin comprises maleic anhydride-modified ethylene-vinyl acetate copolymer.

14. The multilayer tubular molded body as claimed in claim 1, wherein, The thickness of the intermediate layer is 0.01 to 1.5 mm.

15. The multilayer tubular molded body as claimed in claim 1, wherein, The maximum load in the compression bending test of the multi-layered tubular molded body with a span of 200 mm was less than 19 N.

16. The multilayer tubular molded article according to any one of claims 1 to 15, wherein, The deflection of the multilayer tubular molded body in the deflection measurement test at 100℃ was less than 40 mm.

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