JP2019099647A - Production method of resin pipe, resin pipe, and pipeline connection structure - Google Patents

Abstract

To provide an extrusion molded resin pipe having air bubbles that do not substantially communicate in a direction parallel to an extrusion direction provided in a foam layer by using chemical foaming method at low cost.SOLUTION: A resin pipe 100 is produced according to a production method including: a step of making 2 wt.% or more of microcapsules having a swell start temperature of 120°C or higher as a foaming agent contained in a resin before resin molding; and a step of resin molding such that an expansion ratio becomes larger than 2.3 times. The resin pipe has an outer periphery surface (a part of a thickness t) constituted of an outer layer 110 that is an external surface of an outer periphery surface, an inner layer 120 that is an inner surface of the outer periphery surface, and a foaming layer 130 formed between the outer layer 110 and the inner layer 120, the outer layer 110 and the inner layer 120 constitute a non-foaming layer, and air bubbles of the foaming layer 130 do not substantially communicate in a direction parallel to the extrusion direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to, for example, a resin pipe having a heat insulating layer used for a drain pipe line of an air conditioning facility, and in particular, includes a heat insulating layer formed by closed cells which can be manufactured at low cost. The present invention relates to a method of manufacturing a resin pipe which does not require waterproof treatment, and further relates to a resin pipe manufactured by the method and a drainage pipe structure using the resin pipe.

  Conventionally, resin-made piping materials, such as vinyl chloride (it may describe as polyvinyl chloride below), are widely used as piping materials which perform water supply or drainage etc. In such a resin pipe line (which may be simply described as a resin pipe in the following), there are also those requiring heat insulation. For example, in a drain pipe line of an air conditioner, the heat insulation effect is excellent. It is a resin pipe, Comprising: The foamed resin pipe which provided the film layer in the inner and outer peripheral surface of the foam layer is known.

  Such a foamed resin pipe is disclosed in Japanese Patent No. 3415905 (Patent Document 1). This patent document 1 discloses a foamed vinyl chloride pipe formed in a state in which the entire tube contains a large number of cells by foaming, and the large number of cells is intended to exhibit an excellent heat insulating effect. . And as this foamed vinyl chloride pipe, it may be a closed cell type or an open cell type, and a non-foamed skin layer is formed on the outer peripheral surface and / or the inner peripheral surface of the foamed vinyl chloride pipe. It is disclosed in this patent document 1 that it may be done. Although there is no detailed description in Japanese Patent Application Laid-Open No. 2001-266118 about air bubbles that express thermal insulation in such a foamed vinyl chloride pipe, it is technically difficult to resin-mold only with closed cells, and open cells are not included. It is easy to guess that you do not get

  However, when open cells are included in the cells that form the foam layer, drain water penetrates from the pipe end into the foam layer during use as a pipe line to lower the heat insulation performance. It is waterproofed by attaching packing or applying an adhesive to the end of the pipe at the time of construction. For this reason, there is a problem that the heat insulation performance of the resin pipe is deteriorated due to the need for the water blocking packing, the forgetting to attach the water blocking packing or the forgetting to apply the adhesive to the pipe end (both are human errors in waterproofing). There is a point.

  In order to solve such problems, JP-A-2007-283733 (Patent Document 2) discloses a vinyl chloride resin foam layer having a small number of open cells and a uniform cell and a substantially non-foamed vinyl chloride resin. Disclosed is a vinyl chloride-based resin foam tube excellent in heat insulation effect, condensation prevention effect, and the like, in which a resin is laminated and water does not enter between the two layers at the time of bonding with a joint or the like. The resin foam tube disclosed in Patent Document 2 is an extruded vinyl chloride resin foam in which a foam layer is formed between an inner surface skin layer (inner surface coating layer) and an outer surface skin layer (outer surface coating layer). A tube wherein the inner skin layer is substantially non-foamed with a thickness of 0.05 to 0.6 mm and the outer skin layer is substantially non-foamed with a thickness of 0.2 to 1.5 mm Also, the cells of the foam layer do not substantially communicate in the direction parallel to the extrusion direction, and the average cell diameter of the cross section perpendicular to the extrusion direction is 30 to 150 μm, and the foaming ratio of the foam layer is 2 to 5 It is characterized by being doubled.

  In the extruded vinyl chloride resin foam tube disclosed in Patent Document 2, the bubbles forming the heat insulation layer are formed by using a chemical foaming method using azodicarbonamide (ADCA) or the like. Instead, they are formed using a physical foaming method using an inert gas such as nitrogen or carbon dioxide.

Patent No. 3415905 JP 2007-283733 A

The resin tube molded with closed cells in which the bubbles of the foam layer are not substantially communicated in the direction parallel to the extrusion direction as disclosed in Patent Document 2 has a waterproof seal attached to the joint during construction. It is certainly preferable in that the prevention of applying an adhesive to the end of the tube is unnecessary.
However, in order to make the cells of such a foam layer be closed cells so that the drain water does not penetrate into the pipe, the technique disclosed in Patent Document 2 uses a physical foaming method using an inert gas as a foaming agent. There is a problem that a resin tube extrusion manufacturing line including an inert gas supply device for realizing the above is needed, and the manufacturing cost of the resin tube with a heat insulation layer increases (compared to the chemical foaming method).

  The present invention has been developed in view of the above-mentioned problems existing in the prior art, and the object of the present invention relates to a resin pipe provided with a heat insulating layer, and in particular, it is formed by closed cells at low cost. The present invention relates to a method of manufacturing a resin pipe having a heat insulation layer and requiring no waterproofing treatment such as water blocking when connecting pipes, and further providing a resin pipe manufactured by the manufacturing method and a drainage pipe structure using the resin pipe. is there.

In order to achieve the above object, the method for producing a resin pipe, the resin pipe and the drainage pipe structure according to the present invention takes the following technical means.
That is, the manufacturing method according to an aspect of the present invention is a method for manufacturing a resin pipe in which a foam layer is formed. This production method comprises the steps of including 2% by weight or more of microcapsules having an expansion start temperature of 120 ° C. or more as a foaming agent to be contained in the resin before resin molding, and the bubbles of the foam layer in the resin tube are substantially And forming a resin so that the expansion ratio is greater than 2.3 times.

Preferably, the resin pipe can be configured such that a foam layer is formed between the outer surface and the inner surface.
More preferably, resin molding can be performed using a master batch in which the above-mentioned foaming agent is contained in a resin.
More preferably, a chemical foaming agent can be used in combination with the microcapsule as the foaming agent.

More preferably, in addition to 2% by weight or more of the microcapsules, 0.1% by weight or more of azodicarbonamide as the chemical foaming agent may be used in combination to make the expansion ratio larger than 3 times.
More preferably, the composition can be used in combination with the azodicarbonamide at 0.2 wt% or less.

A resin pipe according to another aspect of the present invention is characterized in that it is manufactured by any of the above-described manufacturing methods.
Moreover, the piping connection structure which concerns on the further another aspect of this invention is characterized by connecting the resin pipe mentioned above and other piping materials, without water stop packing.

  The present invention relates to a method for producing a resin pipe provided with a low cost, heat insulating layer formed by closed cells and requiring no waterproofing treatment such as water blocking packing at the time of pipe connection, and a resin pipe produced by the production method The drainage piping structure using the resin pipe can be provided.

It is an external view ((A) front view, (B) left view) of the resin tube concerning embodiment of this invention. It is 2-2 sectional drawing of the resin pipe shown in FIG.

Hereinafter, a resin pipe provided with a heat insulating layer according to an embodiment of the present invention (hereinafter sometimes referred to as a resin pipe with a heat insulating layer or simply a resin pipe), a method for producing the same, and drainage using the resin pipe The piping structure will be described in detail based on the drawings.
FIG. 1 is a plan view ((A) front view, (B) left side view) of a resin pipe 100 manufactured by a manufacturing method according to an embodiment of the present invention, and FIG. Each is shown in FIG. The resin pipe 100 has a straight pipe shape in which the length L in the direction parallel to the extrusion direction is sufficiently larger than the outer diameter φD1 and the inner diameter φD2 in the direction perpendicular to the extrusion direction.
Here, in the left side view shown in FIG. 1 (B) and the cross-sectional view shown in FIG. 2, the bubbles in the foam layer 130 described later are indicated by points, and the non-foam layer (the outer layer 110 and the inner layer 120) and the foam layer A boundary line with 130 is virtually shown by a dotted line.

  The resin pipe 100 is a straight pipe having an outer diameter φD1 and an inner diameter φD2 and a thickness t, and the resin pipe 100 is mainly applied to drain piping. The outer peripheral surface (portion of thickness t) of the resin pipe 100 is formed between the outer layer 110 which is the outer surface of the outer peripheral surface, the inner layer 120 which is the inner surface of the outer peripheral surface, the outer layer 110 and the inner layer 120 And an extruded vinyl chloride resin foam tube. The outer layer 110 and the inner layer 120 constitute a non-foamed layer, and the cells of the foamed layer 130 are characterized in that they do not substantially communicate in the direction parallel to the extrusion direction.

The resin pipe 100 is manufactured by the following manufacturing method.
First, as a foaming agent to be contained in the resin before resin molding, a step of containing 2% by weight or more of microcapsules having an expansion start temperature of 120 ° C. or higher (hereinafter sometimes referred to as a first step) In the step of resin molding (hereinafter referred to as the second step), the cells of the foam layer in the tube are not substantially communicated and independent, and the expansion ratio is greater than 2.3 times There is a).

  Here, “the bubbles in the foam layer are not substantially communicated and independent” means “(1) without water blocking packing when fluid permeates from the end face on one side of the resin pipe 100 "The extent to which the fluid does not leak from the end face on the other side of the resin pipe 100 in the pipe connection structure and (2) the heat insulation performance of the resin pipe does not fall below specifications." It does not mean that all the bubbles in the layer are completely independent foaming, but may include the presence of communicating bubbles, but indicate that they do not communicate more than the above-mentioned level. . Furthermore, "the bubbles of the foam layer are not substantially communicated and independent" means "the tube end a of one side of the resin tube 100 is immersed in water and the other tube end is the other side. Even when b is maintained in a decompressed state, it indicates the extent to which the cut surface is not attacked by water when cut at any position between the pipe end a and the pipe end b.

Specifically, in the first step, it is also preferable to use a masterbatch in which a foaming agent (this foaming agent includes microcapsules and other chemical foaming agents such as azodicarbonamide (ADCA)) is contained in a resin. In this case,
As a foaming agent, in addition to 2% by weight of microcapsules (2% by weight or more), 0.1% by weight of azodicarbonamide (0.1% by weight or more) is used in combination to give a foaming ratio of 3 It is also preferable to make it larger than twice. In this case, it is also preferable to use azodicarbonamide in an amount of 0.2% by weight or less.

The manufacturing method according to the present embodiment having such technical features will be described in more detail.
In reaching the manufacturing method according to the present embodiment, the applicant of the present application has prepared the cylinder temperature of the polyvinyl chloride extruder that is a manufacturing apparatus of the resin pipe 100, the expansion start temperature of the microcapsules to be contained in the polyvinyl chloride resin, and the microcapsule for polyvinyl chloride resin. Studies were conducted intensively on the content rate of and the expansion ratio (expansion rate).

  First, regarding the temperature, if the cylinder temperature of the PVC extruder is higher than the expansion start temperature of the microcapsules, the microcapsules will foam and expand in the cylinder, so the shear force of the PVC extruder screw causes micro The capsule is broken and the expansion ratio of the heat insulating layer is less than twice, and the desired heat insulating effect can not be exhibited. On the other hand, when the cylinder temperature of the polyvinyl chloride extruder is too low (at least below the expansion start temperature of the microcapsules), the extrusion-molded product is crushed and the resin pipe 100 can not be formed.

  In such background, microcapsules in the cylinder of a polyvinyl chloride extruder are made to contain microcapsules having a swelling start temperature of 120 ° C. or more (preferably 130 ° C. or more) in an amount of 2% by weight or more based on the polyvinyl chloride resin. The applicant has reached that the resin tube 100 can be formed with an expansion ratio of 2 times or more (preferably 2.3 times or more) capable of avoiding foam breakage and expressing a desired heat insulation effect. When the expansion ratio is doubled, the weight is reduced by 50%.

  In this case, the periphery of the microcapsules is covered with the carrier resin by resin molding using a master batch in which the microcapsules are contained in a resin. For this reason, the masterbatch is transferred to the mold in a state where the microcapsules do not expand without direct contact between the cylinder of the polyvinyl chloride extruder and the microcapsules. This allows molding at a temperature higher than the foaming start temperature of the microcapsules. Here, as the carrier resin, for example, EVA (Ethylene-Vinyl Acetate copolymer: ethylene vinyl acetate copolymer), PE (Polyethylene: polyethylene), etc. can be considered.

  In order to express a desired heat insulating effect, it is preferable that the expansion ratio be large as long as the cells of the foam layer 130 of the resin tube 100 are not substantially communicated but independent. Therefore, in addition to the microcapsules, a chemical foaming agent is used in combination, for example, in addition to 2% by weight of the microcapsules, 0.1% by weight of azodicarbonamide as a chemical foaming agent is used together (azodicarbonamide is at most 0. The applicant of the present invention has reached that it is possible to form a resin pipe 100 having an expansion ratio of 3 times or more and 2% by weight or less). The azodicarbonamide alone is a continuous foam, but if it is used in combination with a microcapsule, the foam layer 130 is closed cells (the cells of the foam layer 130 do not substantially communicate and become independent) within a range where there is no problem in water repellency in practical use. Air bubbles). If the addition amount of azodicarbonamide is large, it is not preferable because continuous foam is generated and blistering occurs on the surface layer of the resin pipe 100, so the addition amount of azodicarbonamide is 0.2 % By weight or less is preferred.

  By adopting such a production method, that is, by using the microcapsule as the foaming agent in the chemical foaming method, the foam layer 130 which is the intermediate layer is independently foamed (the bubbles of the foam layer 130 of the resin tube 100). The present applicant has arrived at the manufacture of a resin tube 100 in which (1) substantially does not communicate and is independent. If bubbles in the foam layer are connected (if it is an open cell), drain water will intrude into the inside of the resin pipe from the end face of the resin pipe and the heat insulation performance will be reduced. Although it is necessary to apply an adhesive to the end face of the pipe to waterproof it, such a foamed layer 130 of the resin pipe 100 manufactured by the manufacturing method according to the present embodiment is such an independent foam. There is no need for waterproof packing or adhesive application for waterproofing. Further, the manufacturing method according to the present embodiment uses a physical foaming method that requires a resin tube extrusion manufacturing line including an inert gas supply device to manufacture resin tube 100 using a chemical foaming method. Unlike the manufacturing method, the manufacturing cost can be suppressed.

That is, in the drainage pipe structure using the resin pipe 100 shown in FIG. 1 and FIG. 2 manufactured inexpensively by the manufacturing method according to the present embodiment, the foam layer 130 of the manufactured resin pipe 100 is independently foamed. Therefore, it is not necessary to use waterproofing packing or adhesive application as such waterproofing treatment, and connect the resin pipe 100 and other piping material without waterproofing treatment (typically, waterproofing packing) Can.
<Example>
Below, the Example of the resin pipe 100 using the manufacturing method which concerns on this Embodiment is demonstrated in detail.

The resin used in the method for producing the resin pipe 100 according to the present embodiment is not particularly limited, but vinyl chloride is preferable, and for example, polyolefin resin such as polypropylene, polyethylene, polystyrene, propylene / ethylene copolymer, etc. It does not matter. The carrier resin is as described above.
The microcapsules used as a foaming agent in the method for producing a resin tube according to the present embodiment are not particularly limited, but F190D (manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.) having an expansion start temperature of 160 ° C. to 170 ° C. Preferably, for example, H850D (manufactured by Kureha Co., Ltd.) having an expansion start temperature of 130 ° C. to 140 ° C. may be used.

The chemical foaming agent used in the method for producing the resin pipe 100 according to the present embodiment is not particularly limited, but is preferably azodicarbonamide (organic compound), and, for example, bicarbonate (inorganic salt such as sodium bicarbonate) It may be a compound) or the like.
In addition to the above-described resin and the foaming agent (microcapsule, chemical foaming agent), the masterbatch used in the method for producing the resin tube 100 according to the present embodiment may, if necessary, be a known foaming aid, A foam nucleating agent, a foam molding stabilizer, a stabilizer, a UV absorber, an antioxidant, an antistatic agent, a lubricant, a coloring agent, a flame retardant, a crosslinking agent and / or a filler can be blended.

  Here, as the foaming aid, for example, stearic acid salts such as sodium stearate, calcium stearate, magnesium stearate, potassium stearate, zinc stearate, etc., montanic acid such as calcium montanate (octadocosanate), zinc montanate, etc. Higher fatty acid metal salts such as salts, urea or urea compounds, paraffin, and stearoamide etc. may be mentioned.

Moreover, as a foaming nucleating agent, inorganic fillers, such as a talc, a silica, a calcium carbonate, a calcium silicate, etc. are mentioned.
As described above, according to the method for producing a resin pipe according to the present embodiment, not the physical foaming method but the chemical foaming method is employed, so a heat insulating layer formed by closed cells is provided at low cost. It is possible to provide a resin pipe, and further, when piping is connected using this resin pipe, waterproofing treatment such as water blocking packing becomes unnecessary.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

  The present invention is suitable for, for example, a method for producing a resin pipe provided with a heat insulating layer used for a drain pipe line of an air conditioning facility, provided with a heat insulating layer formed by closed cells at low cost, It is particularly preferable for the method of producing a resin pipe which does not require waterproof treatment, and is particularly preferred for a resin pipe produced by the method and a drainage pipe structure using the resin pipe.

100 resin tube 110 outer layer 120 (which is the outer surface of the outer peripheral surface) inner layer 130 (which is the inner surface of the outer peripheral surface) 130 foam layer

Claims (8)

It is a manufacturing method of the resin pipe by which a foaming layer is formed, and
And 2% by weight or more of microcapsules having an expansion start temperature of 120 ° C. or higher as a foaming agent to be contained in the resin before resin molding.
A step of resin molding such that the bubbles of the foam layer in the resin pipe are not substantially communicated and independent, and the expansion ratio is greater than 2.3 times. How to make a tube. The method for producing a resin pipe according to claim 1, wherein the resin pipe has a foam layer formed between an outer surface and an inner surface. The method for producing a resin pipe according to claim 1 or 2, wherein resin molding is performed using a master batch in which the foaming agent is contained in a resin. The method for producing a resin pipe according to any one of claims 1 to 3, wherein a chemical foaming agent is used in combination with the microcapsule as the foaming agent. The foaming ratio is increased to 3 times or more by using 0.1% by weight or more of azodicarbonamide as the chemical foaming agent in addition to 2% by weight or more of the microcapsules. Manufacturing method of resin pipe. The method for producing a resin pipe according to claim 5, wherein the azodicarbonamide is used in combination at 0.2 wt% or less. The resin pipe manufactured by the manufacturing method in any one of Claims 1-6. A pipe connection structure characterized by connecting the resin pipe described in claim 7 and another pipe material without water blocking packing.

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