JP2001141131A - Resin duct having multi-layered structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the acoustic transmission loss characteristic of a resin duct. SOLUTION: The resin duct is of a multi-layered structure consisting of a soft resin and a hard resin over locations to generate the sound including the noise at least in the duct.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow molded plastic hollow article having a multilayer structure, wherein the hollow molded article has at least one layer forming a multilayer structure more than other constituent layers. A molded article characterized in that it is soft or at least one layer forming a multilayer structure is a foamed layer, and preferably a part thereof is basically a single layer or a substantially soft or soft molded article. It has a configuration that is integrally formed.

[0002] For this reason, as a field of application, for example, in the case of a tubular body, it is effective for ducts and pipes that require a sound deadening effect, and when a foam layer is provided, it is effective for ducts and pipes that require sound deadening, heat insulation and heat insulation. Effective for pipes.

In particular, taking an automobile duct as an example, it is necessary to provide an intake duct and adiabatic / heat insulation, which are required to reduce intake noise generated at the time of intake of an engine and to avoid a rise in intake air temperature. This is extremely effective for heater ducts and cooler ducts.

[0004]

2. Description of the Related Art Conventionally, when intake noise is generated in ducts and pipes for automobile intake and noise is generated from ducts and pipes, urethane foam or foam is formed around ducts and pipes in order to suppress the noise. Rubber was applied to prevent the generation of noise due to its sound absorbing effect. Furthermore, in the case of a duct that requires silencing, for example, a method was adopted in which a resonator, etc., which was separately formed in order to suppress the intake noise, was attached to the duct using connecting parts, and the intake noise was eliminated.

[0005] Further, in the case of hollow ducts and pipes for obtaining effects such as heat insulation, heat insulation and noise reduction, non-foamed ducts and pipes are formed in advance by extrusion molding, injection molding, blow molding, or the like. A method has been adopted in which a sheet-like foam or the like is wrapped around the outer periphery of the molded body and fixed to the molded body using an adhesive or the like.

In the case of hollow ducts and pipes, there are few simple straight shapes due to functional requirements.
A three-dimensional or three-dimensional bent shape is required. For this reason,
For automotive engine ducts, metal or resin ducts and rubber ducts and hoses are combined to improve engine vibration absorption and assembly performance, and the connection, assembly, and bellows sections are made of soft rubber hose. Was used.

[0007] Further, since the molded article formed by foaming by extrusion molding or injection molding is a hollow body having a simple shape, it can be used only in limited applications. Other connecting parts had to be used, and there were also problems such as air leaks at the connecting parts.

[0008]

In the above-mentioned conventional method, when it is attempted to obtain a hollow duct / pipe or the like having the effects of noise reduction, heat insulation, heat insulation, etc., a blow having a desired duct / pipe shape can be obtained. When molding is used, a single-layer blow-molded duct / pipe is formed, and then a sheet-like foam having an effect of noise reduction, heat insulation, heat retention, etc. is wound around the blow-molded body. Was cut into a shape that can be wound around a duct / pipe, and then wound around the duct / pipe with a double-sided tape, an adhesive, or the like, and fixed. For this reason, post-processing, such as cutting and cutting loss of the foam, and sticking with a double-sided tape or an adhesive, is required. Not only is processing cost high, but there is also a problem of peeling of the foam attached. In addition, duct
For connection of pipes and bellows for absorbing vibration, it was necessary to use a soft rubber hose or the like.

On the other hand, extrusion molding / injection molding capable of obtaining a foamed molded article can obtain only a simple hollow shape, not only a desired shape, but also a connection portion with other parts. A connection part or the like for connection must be used, and there is also a problem of air leakage at the connection part.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned disadvantages of the prior art and integrally forms a hollow duct / pipe or the like having effects such as noise reduction, heat insulation and heat insulation by blow molding in one step. To provide a product having a desired shape and performance. In other words, a multi-layer structure part having effects such as noise reduction, heat insulation and heat retention, and a single-layer structure part or a substantially soft or hard structure part required for connection and the like are integrally formed in a blow molded article. It is to let.

A first example of a multilayer structure constituted by the present invention is a multilayer structure comprising a relatively soft resin layer and a relatively hard resin layer, and each of the soft resin layer and the hard resin layer is unique. Sound transmission loss characteristics, and complement each other when absorbing noise generated in ducts and pipes, resulting in a better noise absorption effect than the sound transmission loss characteristics of each single layer body. The noise absorption effect is further improved by the vibration damping structure of the laminates having different hardnesses.

In a second example of the multilayer structure constituted by the present invention, a foam layer is provided on the multilayer structure so as to maintain the sound deadening, heat insulation and heat retaining effects of the foam layer.

Further, by providing a single-layer soft or hard portion or a substantially soft or hard multi-layer structure at a portion connected to the multilayer structure, a duct or pipe connection can be achieved. The part and the vibration absorbing part of the bellows structure are integrally blow-molded in one step.

As an example of the molding method according to the present invention,
The soft plastic and the hard plastic plasticized by multiple extruders are combined by the die head of the molding machine, and the parison with the ratio of the soft plastic and the hard plastic changed according to the product shape and required specifications is extruded sequentially. Form a parison with a multilayer part made of hard plastic and a single layer part (or a substantially soft or hard multilayer part), store this parison in a blow mold, and integrally mold it in one step by blow molding Is what you do.

The multilayer body for providing a noise reduction effect or the like can have a multilayer structure in which the thickness of the ratio between the hard plastic and the soft plastic is changed according to the required specifications of the product. The bellows for absorption is a single layer of soft plastic (or a substantially soft multilayer)
To obtain a hollow molded body having desired performance and function. It is also possible to form the assembly portion with a single layer of hard plastic (or a substantially hard multilayer).
Furthermore, brackets and pipes can be added to the molded body by insert molding at the time of blow molding, so that the molded ducts and pipes can be easily attached and fixed.

Another example of the molding method according to the present invention is as follows. A foamed plastic plasticized by a plurality of extruders and a non-foamed plastic are joined together at a die head of a molding machine, and foamed according to the product shape and required specifications. The parison with different ratios of plastic and non-foamed plastic is extruded sequentially to form a parison having a multilayer part made of foamed plastic and non-foamed plastic and a single layer part made of non-foamed plastic, and this parison is stored in a blow mold. , And are integrally formed in one step by blow molding.

The multilayer body portion including the foam layer for maintaining the sound-muffling, heat-insulating, and heat-retaining effects is provided in accordance with the required specifications of the product.
As a multilayer body part with changed thickness and expansion ratio of the foam layer,
The single layer portion can be made of a material necessary for assembly and vibration absorption. Also in this case, brackets and pipes can be added to the molded body by insert molding during blow molding.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 (a) to 1 (d) show a first embodiment according to the present invention, in which an assembling portion provided at a terminal portion of a duct or a pipe is made of relatively soft resin, and a main body portion has a multilayer structure. It is a cross-sectional schematic diagram when it is made into a body.

FIGS. 1 (a) and 1 (b) show that the multilayer
Schematic drawing showing the cross section of the terminal assembling part in the case of a layer, FIG.
(D) is a schematic diagram showing a cross section of the terminal assembling part when the multilayer structure part has three layers.

In FIG. 1A, a blow molded article 1 is
The assembling part 2 is composed of a main body 3 (other parts are omitted). The assembling part 2 is composed of a basically single-layered part made of a relatively soft resin 4, and the main body 3 is relatively It has a two-layer structure of a soft resin 4 and a relatively hard resin 5. This embodiment is an example in which the outer layer of the main body 3 having a multilayer structure is formed of a relatively hard resin 5.

FIG. 1 (b) shows a two-layer structure in which the assembled portion 2 is made of a relatively soft resin 4 and the main body 3 is made of a relatively hard resin 5 as in FIG. 1 (a). This is an example in which the outer layer of the main body 3 is formed of a relatively soft resin 4.

In FIG. 1C, the blow molded body 1a
Is the assembly part 2a and the main body part 3a (other parts are omitted)
And the assembly portion 2a is made of a relatively soft resin 4a.
And the main body 3a has a three-layer structure of a relatively soft resin 4a and a relatively hard resin 5a. In this embodiment, the outer layer 3b and the inner layer 3d of the main body 3a having a multilayer structure are formed of a relatively hard resin 5a, and the intermediate layer 3c is formed of a soft resin 4a.

FIG. 1 (d) shows a three-layered multi-layer structure of a relatively soft resin 4a for the assembly portion 2a and a relatively hard resin 5a as in FIG. 1 (c). Although the outer layer 3b and the inner layer 3 of the main body 3a having a multilayer structure are
This is an example in which d is formed of a relatively soft resin 4a and the intermediate layer 3c is formed of a hard resin 5a.

FIGS. 1 (a) to 1 (d) show that a duct or pipe according to the present invention is externally inserted into a mating part by using a relatively soft resin for an assembly portion provided at a terminal portion of the duct or pipe. This is an example of a configuration in which the main body is composed of two types of two layers and two types of three layers as the configuration of the multi-layered structure part constituting the main body. However, configurations other than the present embodiment are also possible. For example, it is a matter of course that a three-layered three-layer structure, a three-layered five-layer structure, and the like can be adopted.

FIGS. 2 (a) and 2 (b) show a second embodiment according to the present invention, in which an assembly portion provided at the end of a duct or pipe is made of a relatively hard resin, and a main body portion has a multilayer structure. It is a cross-sectional schematic diagram when it is made into a body. When a mating part is externally inserted into the duct or pipe assembly part of the present invention, the duct or pipe assembly part is required to be rigid, but this is an embodiment in that case.

In FIG. 2A, the blow molding 11
Means the assembly part 21 and the main body 31 (other parts are omitted)
And the assembling portion 21 is made of a relatively hard resin 5b.
And the main body 31 has a two-layer structure of a relatively soft resin 4b and a relatively hard resin 5b. In this example, the outer layer of the main body 31 having a multilayer structure is formed of a relatively hard resin 5b. However, the outer layer of the main body 31 may be formed of a relatively soft resin 4b. Of course.

In FIG. 2B, the blow molding 11
Means the assembly part 21 and the main body 31 (other parts are omitted)
And the assembling portion 21 is made of a relatively hard resin 5b.
And the main body 31 has a three-layer structure of a relatively soft resin 4b and a relatively hard resin 5b. In this example, the outer layer 31b and the inner layer 31d of the main body 31 having a multilayer structure are formed of a relatively hard resin 5b, and the intermediate layer 31c is formed of a soft resin 4b. In this example, it is a matter of course that the outer layer 31b and the inner layer 31d of the multilayered main body 31 may be formed of a relatively soft resin 4b, and the intermediate layer 31c may be formed of a hard resin 5b.

FIGS. 3A and 3B show a third embodiment according to the present invention, in which a bellows portion provided in a duct or a pipe is made of relatively soft resin, and a main body portion is made of a multilayer structure. FIG.

In FIG. 3A, the blow molding 12
Is composed of a main body portion 32 and a bellows portion 62 (other portions are omitted). The main body portion 32 has a two-layer structure of a relatively soft resin 4c and a relatively hard resin 5c. Is basically composed of a single layer of relatively soft resin 4c. This is an example in which the outer layer of the main body 32 is formed of a relatively hard resin 5c.

FIG. 3 (b) shows the bellows portion 62 composed of a relatively single layer of relatively soft resin 4c as in FIG. 3 (a), and the main body 32 is made of a relatively soft resin. Resin 4
This is an example of a three-layer structure made of a resin 5c which is relatively harder than the resin c. In this example, the outer layer 32 of the main body 32 having a multilayer structure is used.
This is an example in which b and the inner layer 32d are formed of a relatively hard resin 5c, and the intermediate layer 32c is formed of a soft resin 4c. In this example, the outer layer 32 of the main body 32 having a multilayer structure
Needless to say, b and the inner layer 32d may be formed of a relatively soft resin 4c, and the intermediate layer 32c may be formed of a hard resin 5c.

FIGS. 4 (a) to 4 (c) are schematic cross-sectional views of a fourth embodiment according to the present invention, in which a foam layer is provided on a multilayer component.

FIG. 4A is a schematic cross-sectional view of an example in which the assembly portion is basically a single layer, the main body portion has a multilayer structure, and the multilayer portion has a foam layer. FIG. 4C is a schematic cross-sectional view of an example in which the main body portion has a multilayer structure, the multilayer portion has a foam layer, and basically has a single-layer bellows portion. 3 is a schematic sectional view of an example having a foam layer.

In FIG. 4A, the blow molding 13
Is the assembly part 23 and the main body part 33 (other parts are omitted).
The assembled portion 23 is basically composed of a single layer made of a non-foamed resin 53, and the main body 33 has a two-layer structure made of a foamed resin 43 and a non-foamed resin 53. Although the main body 33 of this example is configured with a two-layer configuration,
Needless to say, a three-layer structure or a multilayer structure having more layers may be used, and the foamed layer may be formed as an intermediate layer of the multilayer structure.

In FIG. 4B, the blow molding 14
Is composed of a main body portion 33 and a bellows portion 63 (other portions are omitted), the bellows portion 63 is basically composed of a single layer portion made of a non-foamed resin 53, and the main body portion 33 is made of a non-foamed resin It has a two-layer structure made of resin 53. Also in this example, the main body 33 has a two-layer structure. However, it is needless to say that a three-layer structure or a multi-layer structure of more layers may be used, and a foamed layer may be formed as an intermediate layer of a multi-layer structure. is there.

In FIG. 4C, the blow molding 15
Is composed of a main body 33 and a bellows 63 (other parts are omitted). Both the main body 33 and the bellows 63 have a multilayer structure, and a foamed resin layer 43 is provided in the multilayer. This example is possible when a relatively soft resin is used for both the foamed resin and the non-foamed resin, and when a duct or a pipe is required to have a vibration absorbing or bending function, and a heat insulating function or a heat retaining function is required. It is valid.

FIGS. 5A to 5C are schematic cross-sectional views of a fifth embodiment according to the present invention, in which the number of multilayer components is three.

FIG. 5A is a schematic view showing a cross section of a terminal assembling portion in a case where the terminal portion has a single layer and the multilayer structure has three layers.
5B is a schematic view showing a cross section of the terminal assembling portion when the terminal portion has two layers and the main body structure portion has three layers, and FIG. 5C is a diagram in which the terminal portion has a single layer and the multilayer structure has two layers. 3 is a conceptual schematic diagram showing a cross section of a terminal assembling portion in the case of a three-layer structure.

In FIG. 5A, the blow molding 16
Is the assembly part 26 and the main body part 36 (other parts are omitted).
And the assembly portion 26 is made of a relatively soft resin 46.
The main body 36 is made of a soft resin 46, a resin 56 that is relatively harder than the soft resin 46, and a resin 66 that is relatively harder than the resin 56.
In a three-layer structure. The resin 46 of the assembly part is
In order to improve workability, the softest resin is used, and the main body is made of three types of resins having different hardnesses, so that the inherent sound transmission loss characteristics of the three types of resins can be utilized. it can. This example is an example in which a resin 56 having an intermediate hardness is formed on the outer layer 36a of the main body portion 36 having a multilayer structure, a hardest resin 66 is formed on the intermediate layer 36b, and a soft resin 46 is formed on the inner layer 36c. Other construction orders are also possible, and the assembly part 26 may be made of a hard resin 66 and the main body part 36 may be made of a three-layer structure.

In FIG. 5B, the blow molding 17
Is the assembly part 27 and the main body part 37 (other parts are omitted).
The assembly portion 27 is composed of a soft resin 47 and a two-layer portion made of a soft resin 57 which is relatively harder than the soft resin 47, and the main body portion 37 is formed of the soft resin 47 and the soft resin 5.
7 and three layers of hard resin 67. The outer layer 27a of the assembly portion 27 is made of a relatively hard soft resin 57, and the inner layer 27b is made of a relatively soft soft resin 47,
It is possible to improve the sealing property of the assembly portion. Further, the main body portion 37 provides the blow molded body 17 with mechanical strength by providing the hard resin 67 in the intermediate layer 37b, and also provides a noise absorbing effect by a multilayer vibration damping structure made of materials having different hardnesses. be able to.

In FIG. 5C, the blow molding 18
Is the assembly part 28 and the main body part 38 (other parts are omitted).
And the assembly portion 28 is made of a relatively soft resin 48.
And the main body 38 is composed of two layers.
It is composed of a layer part 38a and a three-layer part 38b. The assembly portion 28 is formed of a single layer of a relatively soft resin 48,
The two-layer portion 38 a of the main body 38 is made of a soft resin 48 and a resin 58 that is relatively harder than the soft resin 48. Further, the three-layer portion 38 b of the main body 38 is made of a soft resin 48, a resin 58 that is relatively harder than the soft resin 48, and a resin 68 that is relatively harder than the resin 58.

There are various requirements for the characteristics required for ducts and pipes. In addition to flexibility and mechanical strength, heat resistance, pressure resistance, oil resistance, chemical resistance, etc. are required. You. In order to satisfy such required quality, it is effective to combine resin materials having excellent properties. As in the fifth embodiment, by combining resin materials having different hardness and different physical properties, it is effective to combine resin materials having different properties. In addition to the noise absorbing effect obtained by the present invention, other required qualities can be satisfied.

FIG. 6 shows experimental data of sound transmission loss for a multilayer resin duct (two-layer and three-layer) manufactured according to the present invention and a conventional single-layer resin duct. In each case, the layer thickness of the duct is 3t, which is the same, and "t" represents a unit thickness (mm). "PA6-GF 30%" means polyamide 6 reinforced with glass fiber at 30%, and has a flexural modulus of 680.
It is a hard material of 0 MPa. "PA11 (Soft)"
Means polyamide 11, having a flexural modulus of 147M.
Pa is a soft material. As can be seen from FIG.
Compared to a single-layer duct made of only A6GF or PA11, the sound transmission loss is increased over the entire band by using a combination of hard PA6GF and soft PA11 in a multilayer structure for the same layer thickness (3t). . As can be understood from FIG.
A remarkable increase in transmission loss due to the multilayer structure is obtained in the kHz range, which indicates that it is extremely effective in preventing noise in the middle and high frequency range in the audible range. This example shows the effect of one example of the embodiment, and it goes without saying that the amount of sound transmission loss and the frequency band showing the effect can be changed by changing the combination of materials and other ratios.

While the representative embodiments have been described with reference to the schematic partial sectional views, these configurations can be combined with various modes, and the configurations derived from these embodiments are combined with various modes. Of course, it is also possible.

The resin usable in the above embodiment is a thermoplastic resin, and any resin can be used as long as it can be blow-molded. For example, polypropylene (PP), high-density polyethylene (HDP)
E), polyamide (PA), polybutylene terephthalate (PBT), polyethylene terephthalate (PE)
T), resins such as polyphenylene sulfide (PPS), polycarbonate (PC), and polystyrene (PS) can be used. In the case where the resin is harder and needs mechanical strength or heat resistance, the resin is made of glass fiber reinforced polypropylene (PP-GF), glass fiber reinforced polyamide (PA-GF), or glass fiber reinforced. Polybutylene terephthalate (PBT-GF), glass fiber reinforced polyphenylene sulphite (PPS-GF)
Alternatively, a resin to which a reinforcing material such as talc or mica is added can be used.

Examples of relatively soft resins include blowable resins such as thermoplastic elastomers, and include olefin-based elastomers (TPO), polyamide-based elastomers (TPAE), polyester-based elastomers (TEEE), and styrene. Elastomers, polyurethane elastomers, relatively soft low-density polyethylene (LDPE), ethylene / vinyl acetate copolymer (EVA), and the like can be used.

Further, in order to form a foamed layer in the above-described embodiment, as the foaming agent added to the resin, any foaming agent that thermally decomposes or reacts may be used. For example, an organic foaming agent may be used. For example, ADCA, ABFA, DPT,
THT, OBSC, TSC, etc. are effective. Of course, a foaming aid can also be used, and by using the foaming aid together, the desired foaming temperature, foaming ratio, foaming diameter (foam diameter), etc. can be easily controlled.

The above embodiment is an example of an embodiment of the present invention, and it goes without saying that various embodiments other than the above embodiment are possible.

[0049]

The effects of the present invention are as follows.

In a resin duct having a multilayer structure, (1) a hollow body having a desired sound shape and a connection function can be integrally formed in one step by blow molding.

(2) A molded article having a vibration absorbing effect in addition to the sound deadening effect and the heat insulating effect of the foam layer can be obtained.

(3) A molded article obtained by adding resin-added parts such as brackets and pipes to the molded article is obtained.

(4) The parts required for the conventional noise reduction can be reduced, and the cost and parts can be reduced.

[Brief description of the drawings]

FIGS. 1A, 1B, 1C, and 1D are schematic cross-sectional views showing an embodiment of a portion composed of a single-layer portion and a multilayer portion of the first embodiment.

FIGS. 2A and 2B are schematic cross-sectional views showing a mode of a portion composed of a single-layer portion and a multilayer portion of a second embodiment.

FIGS. 3A and 3B are schematic cross-sectional views showing a mode of a portion having a bellows portion according to a third embodiment, the portion being composed of a single-layer portion and a multilayer portion.

FIGS. 4A, 4B, and 4C are schematic cross-sectional views of a fourth embodiment having a foam layer.

FIGS. 5 (a), (b) and (c) show 3 of the fifth embodiment.
The schematic diagram which shows the cross section of the example of a layer molded object.

FIG. 6 is a graph showing a comparison of sound transmission loss experimental data between a multilayer duct of the present invention and a conventional single-layer duct.

[Explanation of symbols]

1,1a, 11,12,13,16,17,18 Blow molded body 2,2a, 21,23,26,27,28 Assembly part 3,3a, 31,32,33,36,37,38 Main body Part 4, 4a, 4b, 4c, 46, 47, 48, 57 Soft resin 5, 5a, 5b, 5c, 56, 58, 67 Hard resin 27b, 32d Internal layer 32b External layer 43 Foaming resin 53 Non-foaming resin 62, 63 bellows

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 9:00 B29L 9:00 23:00 23:00 F-term (Reference) 3H025 CA01 CB01 CB41 3H111 AA02 BA15 CA47 CB03 CB04 CB27 CB28 DA13 DA15 DA26 DB11 DB20 EA06 3L080 AD02 AE01 AE02 4F208 AA00 AG03 AG08 AG10 AG20 LA08 LB01 LB22

Claims (9)

[Claims] In a resin duct formed by blow molding, the resin duct has a multilayer structure, and at least one of the resin layers forming the multilayer structure is relatively softer than other constituent resin layers. A resin duct, characterized in that: 2. A resin duct formed by blow molding, wherein the resin duct has a substantially single-layer portion and a substantially multilayer portion, and at least one of resin layers forming a substantially multilayer structure. One of the layers is substantially composed of a resin forming a single layer, and the substantially single-layer part and the substantially multilayer part of the resin duct are continuously and gradually switched. And a resin duct. 3. The resin according to claim 2, wherein the resin forming the substantially single layer is relatively soft with respect to the other constituent resins forming the multilayer, and the portion substantially forming the single layer is the resin. A resin duct, which forms at least an assembly portion or a bellows portion of the resin duct. 4. The resin according to claim 2, wherein the resin that substantially forms a single layer is relatively harder than other constituent resins that form a multilayer, and the portion that substantially forms a single layer is the resin. A resin duct, which forms an assembly part of the resin duct. 5. In a resin duct formed by blow molding, the resin duct has a multilayer structure, and at least one of the resin layers forming the multilayer structure is relatively softer than other constituent resin layers. A resin duct, comprising: a multi-layer part which is substantially and relatively soft and a multi-layer part which is substantially and relatively hard. 6. The resin duct as claimed in claim 5, wherein the substantially and relatively soft multilayer portion or the substantially and relatively hard multilayer portion forms an assembly portion of the resin duct. Characteristic resin duct. 7. A resin duct according to claim 1, wherein additional parts such as brackets and pipes are added to said resin duct. 8. A resin duct formed by blow molding, wherein the resin duct has a multilayer structure, and at least one of the resin layers forming the multilayer structure has a foamed resin layer. Made duct. 9. A resin duct formed by blow molding, wherein the resin duct has a substantially single-layer portion and a substantially multilayer portion, and at least one of resin layers forming a substantially multilayer structure. A resin duct, characterized in that one of the layers has a foamed resin layer, and a substantially single layer portion and a substantially multilayer portion of the resin duct are continuously and gradually switched.