JP7254577B2 - Piping material - Google Patents

Description

The present invention relates to piping materials.

A piping material having a foam layer for imparting excellent heat insulating performance has been proposed as a piping material, especially a piping material used for air conditioning drains, air conditioners, dew condensation prevention piping, etc. (Patent Document 1).

However, with such conventional piping materials, in order to satisfy the fire resistance performance stipulated by ISO (International Organization for Standardization), it is necessary to apply a special treatment when installing the piping materials, which is costly and labor intensive. It is a heavy burden on the surface.

Therefore, it is conceivable to provide a layer having fire resistance on the piping material itself. However, when a layer having fire resistance is provided, the thickness of the heat insulation layer must be designed to be thin in consideration of the existence of the layer, and as a result, even if fire resistance can be obtained, sufficient heat insulation performance has the disadvantage of not being able to obtain

Thus, there is a demand for a piping material that can achieve both thermal insulation performance and fire resistance performance.

JP 2007-283733 A

In view of the circumstances as described above, an object of the present invention is to provide a piping material capable of achieving both heat insulation performance and fire resistance performance.

The present inventors have made intensive studies to achieve the above object, and as a result, have found that it is possible to achieve both thermal insulation performance and fire resistance performance of the piping material by providing the piping material with a foam layer containing expanded graphite. . The inventors of the present invention conducted further studies based on such knowledge, and completed the present invention.

That is, the present invention provides the following piping material.
Section 1.
A piping material having a tubular foam layer containing a thermoplastic resin and expanded graphite, wherein the foam layer contains 2 to 50 parts by mass of the expanded graphite with respect to 100 parts by mass of the thermoplastic resin.
Section 2.
Item 2. The piping material according to item 1, which has a coating layer on at least one of the outside and the inside of the foam layer.
Item 3.
Item 3. The piping material according to Item 1 or 2, wherein the foam layer has an expansion ratio of 2 to 10.
Section 4.
4. The piping material according to any one of Items 1 to 3, wherein the expanded graphite has an average particle size of 100 to 600 μm.
Item 5.
Item 5. The piping material according to any one of Items 1 to 4, wherein the thermoplastic resin is a polyvinyl chloride resin.

The piping material of the present invention has excellent heat insulation performance and fire resistance performance.

An example of sectional drawing of the piping material of this invention. The top view of an example of the manufacturing apparatus of the piping of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The front view of an example of the manufacturing apparatus of the piping of this invention. FIG. 2 is a configuration diagram showing an example of a mold used in the pipe manufacturing apparatus of the present invention and a pipe outer surface forming tube.

1. Piping Material The piping material of the present invention has a tubular foam layer. The foam layer contains a thermoplastic resin and expanded graphite.

2. Foam Layer The piping material of the present invention may have a single-layer structure consisting only of the above tubular foam layer, or may have a multi-layer structure including a coating layer, which will be described later. The thickness of the foam layer is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more of the total thickness. By having such a configuration, the piping material of the present invention can exhibit sufficient heat insulation performance and expansion performance when heated. For example, in the case of a nominal diameter of 50, the thickness of the foam layer is preferably 5.5 mm with respect to the overall thickness of 9.5 mm. The thickness dimension is not particularly limited, and particularly the overall thickness and foam layer thickness are appropriately selected according to the application and use environment.

A wide range of known thermoplastic resins can be used as the thermoplastic resin, and there is no particular limitation. Specifically, polyethylene-based resin, chlorinated polyethylene-based resin, polypropylene-based resin, polyvinyl chloride-based resin, polystyrene-based resin, polybutene-based resin, polyvinyl acetate-based resin, polyurethane-based resin, polyethylene terephthalate-based resin, ethylene- At least one selected from the group consisting of propylene copolymer-based resin, ethylene-ethyl acrylate copolymer-based resin, Teflon (registered trademark)-based resin, ABS-based resin, AS-based resin, and acrylic-based resin can be used. is.

Among those mentioned above, it is preferable to use a polyvinyl chloride resin in consideration of the strength and durability of the piping material. In addition, it is also preferable to use vinyl chloride monomers and copolymers of the vinyl chloride monomers with other monomers copolymerizable therewith.

Here, other monomers copolymerizable with the vinyl chloride monomer are not particularly limited, and examples include ethylene, propylene, allyl chloride, acrylic acid, methacrylic acid, acrylic acid esters, and methacrylic acid esters. , vinyl acetate, maleic anhydride, and acrylonitrile. These may be used alone or in combination of two or more.

However, acrylic acid, methacrylic acid, acrylic acid esters, or methacrylic acid esters (collectively referred to as acrylic polymer compounds) are used as other monomers copolymerizable with the above vinyl chloride monomers. preferably. By including the acrylic polymer, the closed cell ratio in the foam layer can be improved, and the cell diameter can be made finer.

The mass average molecular weight of the acrylic polymer compound is preferably 3 million or more and 6 million or less, more preferably 4 million or more and 5 million or less.

When the foam layer contains an acrylic polymer compound, the content of the acrylic polymer compound is preferably 10 parts by mass or more and 50 parts by mass or less, and 12 parts by mass or more with respect to 100 parts by mass of the thermoplastic resin. It is more preferably 36 parts by mass or less, and even more preferably 18 parts by mass or more and 24 parts by mass or less.

The average degree of polymerization of the thermoplastic resin used is preferably 600-800, more preferably 600-700. The average degree of polymerization can be calculated by dividing the weight average molecular weight by the molecular weight of chloroethylene.

The foam layer contains expanded graphite in addition to the thermoplastic resin described above. It is preferable that particulate expanded graphite exists in a dispersed state in the foamed layer. The piping material of the present invention exhibits fire resistance by blocking the piping due to the expansion of the expanded graphite (high expansion ratio) due to the heat of the fire and preventing the spread of fire through the piping.

Expanded graphite is a conventionally known substance, and powders such as natural flake graphite, pyrolytic graphite, and Kish graphite are mixed with inorganic acids such as concentrated sulfuric acid, nitric acid, and selenic acid, and concentrated nitric acid, perchloric acid, perchlorate, and perchlorate. A graphite intercalation compound is produced by treating with a strong oxidizing agent such as manganate, bichromate, or hydrogen peroxide, and is a crystalline compound that maintains the layered structure of carbon.

The content of the expanded graphite in the foam layer is preferably 2 parts by mass or more, preferably 10 parts by mass or more, with respect to 100 parts by mass of the thermoplastic resin in order to obtain an appropriate expansion ratio of the pipe. is more preferable. On the other hand, in consideration of moldability, the amount of expanded graphite contained in the foam layer is preferably 50 parts by mass or less, more preferably 40 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin.

When the expanded graphite is dispersed in particles in the foamed layer, the average particle diameter of the particles is 100 μm or more for ensuring sufficient expansion performance of the foamed layer when heated (fired). , and more preferably 200 μm or more. On the other hand, the average particle size of the expanded graphite present in the foam layer is preferably 600 μm or less, more preferably 400 μm or less, in order to facilitate molding of the piping material.

In this specification, the average particle size of the expanded graphite is obtained by dividing 100 g of expanded graphite into meshes using a test sieve based on JIS Z8801-1, and calculating the size of the mesh opening of the test sieve (μm) × the weight of the mesh on. (g)/total weight (g).

A wide range of known foaming agents can be used, and there is no particular limitation. Specifically, thermally decomposable organic foaming agents such as azodicarbonamide (ADCA) and sulfonylhydrazide, and thermally decomposable inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate, and ammonium carbonate can be used. These may be used individually by 1 type, and may use 2 or more types together.

In addition to this, physical foaming is performed by supplying a low boiling point organic compound such as butane, pentane, dichlorodifluoromethane, etc. to the place where the resin is melted in the molding machine, kneading it, and discharging it into the low pressure area. It is also preferable to form the foam layer using a method.

The foaming ratio of the foam layer is preferably 2 or more, more preferably 3.5 or more, from the viewpoint of imparting sufficient heat insulating properties to the piping material. On the other hand, considering moldability, the expansion ratio is preferably 10 or less, more preferably 6 or less.

Incidentally, in this specification, the calculation of the expansion ratio is defined as being obtained by the following method.

10 mm or more in the circumferential direction and 50 mm in the axial direction are cut from a tubular shape, the coating layer described later is cut with a milling machine, and only the foam layer is processed into a plate shape of about 50 mm in length to obtain a test piece. In addition, four test pieces shall be prepared centering on points which are evenly divided into four in the inner peripheral direction. According to JIS K 7112:1999, the apparent density of the test piece is determined to three digits after the decimal point with a water displacement type specific gravity meter at 23°C ± 2°C, and the foaming ratio is calculated by the following formula (1).
m=γc/γ (1)
[In formula (1), m is the expansion ratio, γ is the apparent density (g/cm ³ ) of the foamed layer,
γc is the unfoamed density (g/cm ³ ) of the foamed layer. ]

In addition, stabilizers, stabilizing aids, lubricants, processing aids, impact modifiers, antioxidants, light stabilizers, ultraviolet Additives such as absorbents, fillers, pigments, plasticizers, etc. may be added.

3. Coating Layer As shown in FIG. 1, it is also preferable to provide a coating layer on at least one of the outside and the inside of the foam layer 1 . Hereinafter, in this specification, the cylindrical coating layer provided inside the foam layer is also referred to as the inner coating layer 2 , and the cylindrical coating layer provided outside the foam layer is also referred to as the outer coating layer 3 .

3.1. Coating inner layer The coating inner layer preferably contains a vinyl chloride resin (A). The vinyl chloride resin (A) may be a homopolymer of a vinyl chloride monomer (polyvinyl chloride), or a vinyl chloride monomer and another monomer copolymerizable with the vinyl chloride monomer. It may be a copolymer with a body.

Other monomers copolymerizable with the vinyl chloride monomer include, for example, ethylene, propylene, allyl chloride, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, vinyl acetate, maleic anhydride, acrylonitrile. and other monomers. These may be used alone, or two or more of them may be used in combination.

The vinyl chloride resin (A) may be used alone, or two or more of them may be used in combination.

The inner coating layer may contain a thermoplastic resin other than the vinyl chloride resin (A). Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, polybutene, chlorinated polyethylene, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, polyethylene terephthalate, ABS resin and acrylic resin. These may be used alone, or two or more of them may be used in combination.

In the coating inner layer, the content of the vinyl chloride resin (A) with respect to the total mass of the resin is preferably 80% by mass or more and 95% by mass or less, more preferably 85% by mass or more and 90% by mass or less.

The thickness of the inner coating layer is preferably 1.0 mm or more and 5.0 mm or less, more preferably 1.5 mm or more and 3.5 mm or less. By setting the thickness of the coating inner layer within the above numerical range, there is no risk of water penetrating into the foam layer when water is passed through the interior, and good heat insulation of the piping material can be ensured. .

On the other hand, when the closed cell ratio of the foam layer is high, the foam layer itself prevents permeation of water. Moreover, since the thickness of the foam layer can be increased, the heat insulation of the piping material can be improved.

3.2. Coating outer layer The coating outer layer preferably contains a vinyl chloride resin (B). The vinyl chloride resin (B) may be a homopolymer of a vinyl chloride monomer (polyvinyl chloride), or a vinyl chloride monomer and another monomer copolymerizable with the vinyl chloride monomer. It may be a copolymer with a body.

Other monomers copolymerizable with the vinyl chloride monomer include, for example, ethylene, propylene, allyl chloride, acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, vinyl acetate, maleic anhydride, acrylonitrile. and other monomers. These may be used alone, or two or more of them may be used in combination.

The vinyl chloride resin (B) may be used alone, or two or more of them may be used in combination.

The coating outer layer may contain a thermoplastic resin other than the vinyl chloride resin (B). Examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, polybutene, chlorinated polyethylene, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, polyethylene terephthalate, ABS resin and acrylic resin. These may be used alone, or two or more of them may be used in combination.

In the coating outer layer, the content of the vinyl chloride resin (B) with respect to the total mass of the resin is preferably 80% by mass or more and 95% by mass or less, more preferably 85% by mass or more and 90% by mass or less.

The vinyl chloride resin (B) may be the same as or different from the vinyl chloride resin (A) in the inner coating layer.

The vinyl chloride resin (B) may be the same as or different from the vinyl chloride resin in the foam layer.

The thickness of the coating outer layer is preferably 0.6 mm or more and 1.5 mm or less, more preferably 1.0 mm or more and 1.3 mm or less. By making the thickness of the coating outer layer equal to or greater than the above lower limit, the piping material can be made resistant to impact from the outside. By making the thickness of the coating outer layer equal to or less than the above upper limit, the weight of the piping material can be reduced. Moreover, since the thickness of the foam layer can be increased, the piping material can be made excellent in heat insulation.

In order to increase the strength against external impact, the thickness of the outer covering layer is preferably 1.0 mm or more and 5.0 mm or less, more preferably 1.5 mm or more and 3.5 mm or less.

The outer coating layer may contain a pigment. Appearance can be improved by containing a pigment.

4. Manufacturing Method of Piping Material The piping material of the present invention can be manufactured by a conventional method, and the manufacturing method is not particularly limited. Mainly, it can be manufactured by adopting extrusion molding.

More specifically, a foaming layer extruder, and, if necessary, a coating outer layer extruder and / or a coating inner layer extruder are provided, and a mold is connected to these extruders. It is possible to

An example of a specific embodiment of the method for manufacturing a piping material of the present invention will be described below with reference to the drawings.

2 and 3 are general configuration diagrams of a manufacturing apparatus 20 for manufacturing the piping material 10'. The manufacturing apparatus 20 preferably comprises a foam layer extruder 12 , a mold 13 , a cooling water bath 15 , a take-up machine 16 and a cutting machine 17 . Moreover, when manufacturing a piping material provided with a coating outer layer and/or a coating outer layer, it is preferable to provide an inner/outer layer extruder 11 as necessary.

A mold 13 may be connected to the inner/outer layer extruder 11 and the foamed layer extruder 12 , and a cooling water tank 15 may be connected to the mold 13 . Furthermore, it is preferable that a take-up machine 16 is connected to the cooling water tank 15 and a cutting machine 17 is connected to the take-up machine 16 . Furthermore, as shown in FIGS. 2 and 3, a gas cylinder 18 and a metering pump 19 may be connected to the foamed layer extruder 12 .

A gas cylinder 18 and a metering pump 19 supply a gaseous foaming agent from a vent hole of the foam layer extruder 12 .

The inner and outer layer extruder 11 melt-kneads the thermoplastic resin composition for the non-foamed layer forming the non-foamed inner layer 1 and the non-foamed outer layer 3 and extrudes it into the mold 13 .

The foam layer extruder 12 melts and kneads the thermoplastic resin composition for forming the foam layer 2 and extrudes it into the mold 13 .

The mold 13 contains the thermoplastic resin composition for the foam layer injected from the foam layer extruder 12, and the thermoplastic resin composition for the outer coating layer and/or the inner coating layer injected from the interior and exterior extruder 11 as necessary. The uncured piping material 100' is molded from the material.

The cooling water tank 15 is attached with a pipe outer surface forming tube 14 for forming the unhardened pipe material 100′ into a predetermined size, and the outer surface of the unhardened pipe material 100′ formed by the mold 13 is It cools while being in contact with the pipe outer surface forming tube 14 .

The take-up machine 16 receives the piping material 10 ′ cooled in the cooling water tank 15 .

The cutting machine 17 cuts the piping material 10' sent from the take-up machine 16 to a predetermined length.

First, when adopting the mode of forming a coating layer, the thermoplastic resin composition for the coating layer is supplied to the inner/outer layer extruder 11 and melt-kneaded. Separately, the thermoplastic resin composition for the foam layer is supplied to the foam layer extruder 12 and melt-kneaded. At this time, when gas is used as a foaming agent, the gas in the gas cylinder 18 is supplied from the vent hole by the pumping operation of the metering pump 19 while the thermoplastic resin composition for the foam layer is being melted and kneaded. When a solid or liquid foaming agent is used, the foaming agent may be blended in advance with the thermoplastic resin composition for the foam layer.

Then, for example, when adopting a three-layer structure of a foam layer, an outer coating layer, and an inner coating layer, as shown in FIG. , The foam layer thermoplastic resin composition 22 melted and kneaded by the foam layer extruder 12 is injected into the mold 13 and joined inside the mold 13 to form an uncured piping material 100 ′ having a three-layer structure. to mold. The uncured piping material 100 ′ is the thermoplastic resin composition for the foam layer between the thermoplastic resin layer 31 for the coating layer formed from the thermoplastic resin composition 21 for the coating layer and the thermoplastic resin composition for the foam layer between the inner coating layer 1 and the outer coating layer 3 and a foamed thermoplastic resin layer 32 formed from the material 22 .

Furthermore, when the uncured piping material 100' is ejected from the mold 13, the resin of the foamed thermoplastic resin layer 32 foams. The unhardened piping material 100' is inserted into the outer surface forming tube 14, and the unhardened piping material 100' is molded to a predetermined size and cooled in the cooling water tank 15 to form the piping 10'. Further, the pipe material 10' that has been cooled and formed is handed over to a take-up machine 16, sent to a cutting machine 17, and cut to a predetermined length by the cutting machine 17. - 特許庁

The temperature for molding with the mold 13 is preferably 140° C. or higher and 200° C. or lower, and more preferably 160° C. or higher and 190° C. or lower.

The molding time is preferably 10 minutes or more and 30 minutes or less, more preferably 10 minutes or more and 20 minutes or less.

Although the embodiments of the present invention have been described above, the present invention is by no means limited to such examples, and can of course be embodied in various forms without departing from the gist of the present invention.

EXAMPLES Hereinafter, embodiments of the present invention will be described more specifically based on Examples, but the present invention is not limited to these.

Piping materials of Examples 1 to 6 and Comparative Examples 1 to 3 were manufactured using the manufacturing apparatus shown in FIGS. 2 to 4 according to the compositions shown in Table 1 below.

(Foam state evaluation)
The cross section of each of the manufactured examples and comparative examples was visually observed to confirm whether bubbles were formed in the cross section. A state in which air bubbles are interconnected and cannot be formed is defined as broken bubbles. In Table 1, ◯ indicates that sufficient foaming was confirmed, and x indicates that the foam was broken.

(Expansion ratio evaluation)
A test piece made into a plate shape by roll pressing was cut into a rectangular parallelepiped shape, and the thickness, length, and width were measured at three points with vernier calipers. After that, the test pieces of each example and comparative example were placed in an electric furnace heated to 950° C. for 4 minutes to expand. After that, it was taken out from the electric furnace and left to cool at room temperature. The thickness, length, and width of the expanded test piece after standing to cool are measured with a caliper, and the expansion ratio R is calculated by the following formula. If the expansion ratio R is 10 or more, it is considered to have a practically sufficient coefficient of thermal expansion. It was judged.
Expansion ratio: R = (a1b1c1) / (a0b0c0)
a0: Specimen thickness before expansion (mm)
b0: vertical length of test piece before expansion (mm)
c0: test piece lateral length before expansion (mm)
a1: Specimen thickness after expansion (mm)
b1: vertical length of test piece after expansion (mm)
c1: lateral length of test piece after expansion (mm)

As shown in Table 1, the piping material of each example had a high expansion ratio, and thus it was confirmed that the piping had high fire resistance. It was also confirmed that the foamed layer of the piping material of each example had a good foaming state and sufficient heat insulating performance. On the other hand, it was confirmed that either or both of the fire resistance performance and the heat insulation performance were insufficient in the piping materials of the comparative examples.

1 coating inner layer 2 foam layer 3 coating outer layer 10' piping material 11 coating inner and outer layer extruder 12 foam layer extruder 13 mold 14 pipe outer surface forming tube 15 cooling water tank 16 take-up machine 17 cutting machine 18 gas cylinder 19 metering pump 20 manufacturing apparatus 21 Thermoplastic resin composition for covering layer 22 Thermoplastic resin composition for foaming layer 31 Thermoplastic resin layer for covering layer 32 Foamed thermoplastic resin layer 100' Uncured piping material

Claims (4)

having a tubular foam layer containing a thermoplastic resin and expanded graphite ;
The foam layer contains 15 to 50 parts by mass of the expanded graphite with respect to 100 parts by mass of the thermoplastic resin,
A piping material , wherein the expanded graphite has an average particle size of 100 to 600 μm . 2. The piping material according to claim 1, having a coating layer on at least one of the outside and the inside of said foam layer. 3. The piping material according to claim 1, wherein the foam layer has an expansion ratio of 2 to 10. The piping material according to any one of claims 1 to 3 , wherein the thermoplastic resin is a polyvinyl chloride resin.

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