JP2018059633A - Air-conditioning drain pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air-conditioning drain pipe strong in impact from the outside.SOLUTION: An air-conditioning drain pipe 10 includes a cylindrical foam layer 2 containing a vinyl chloride-based resin B, and a non-foam outer layer 3 provided on an outer surface of the foam layer and containing vinyl chloride-based resin A, where an expansion rate of the foam layer is 3.5 times or more, the vinyl chloride-based resin A is a mixture of vinyl chloride resin and elastomer resin, or a graft polymer that elastomer resin is subjected to graft polymerization on the vinyl chloride resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an air conditioning drain pipe.

  As an air-conditioning drain pipe, a pipe excellent in heat insulation is required. Such an air conditioning drain pipe includes a vinyl chloride resin, and has a foam layer, a non-foamed inner layer laminated on the inner surface of the foamed layer, and a non-foamed outer layer laminated on the outer surface of the foamed layer. A layered tube is preferably used.

  Patent Document 1 proposes a method of manufacturing a three-layered tube by forming a coating layer by cooling the outer surface of a thermoplastic resin composition for a foam layer during extrusion molding.

Japanese Patent Laying-Open No. 2015-96314

  However, the tube obtained by the method of Patent Document 1 has a problem that it is weak against an external impact and easily cracked.

  An object of the present invention is to provide an air conditioning drain pipe that is resistant to external impact.

The present invention has the following aspects.
[1] A cylindrical foam layer containing a vinyl chloride resin (B);
A non-foamed outer layer provided on the outer surface of the foamed layer and comprising a vinyl chloride resin (A),
The foaming ratio of the foamed layer is 3.5 times or more,
The air-conditioning drain pipe, wherein the vinyl chloride resin (A) is a mixture of a vinyl chloride resin and an elastomer resin, or a graft polymer obtained by graft polymerization of an elastomer resin to a vinyl chloride resin.
[2] The air-conditioning drain pipe according to [1], wherein the vinyl chloride resin contained in the vinyl chloride resin (A) has an average degree of polymerization of 800 or more and 1000 or less.

  ADVANTAGE OF THE INVENTION According to this invention, the pipe | tube for air-conditioning drains strong against the impact from the outside can be provided.

It is sectional drawing which shows an example of the pipe for air-conditioning drains of this invention. It is a front view which shows the apparatus for measuring fusion strength. It is sectional drawing which shows the other example of the pipe for air-conditioning drains of this invention. It is a top view of the manufacturing apparatus for manufacturing the pipe for air-conditioning drains. It is a front view of the manufacturing apparatus for manufacturing the pipe for air-conditioning drains. It is a block diagram which shows the metal mold | die and tube for pipe | tube outer surface shaping | molding used for the manufacturing apparatus of the pipe for air-conditioning drains. It is a top view of the manufacturing apparatus for manufacturing the pipe for air-conditioning drains of the comparative example 2. It is a front view of the manufacturing apparatus for manufacturing the pipe for air-conditioning drains of the comparative example 2. It is a block diagram which shows the metal mold | die used for the manufacturing apparatus of the pipe for air conditioning drains of the comparative example 2, a pipe outer surface adjustment apparatus, and a cooling device. It is an enlarged view of the A section in FIG.

≪Air conditioning drain pipe≫
The air-conditioning drain pipe of the present invention includes a cylindrical foam layer containing a vinyl chloride resin (B), and a non-foam outer layer provided on the outer surface of the foam layer and containing the vinyl chloride resin (A). .
FIG. 1 is a cross-sectional view showing an example of an air conditioning drain pipe of the present invention. As shown in FIG. 1, the air conditioning drain pipe 10 includes a tubular foamed layer 2 and a non-foamed outer layer 3 laminated on the outer surface of the foamed layer 2.

The air-conditioning drain pipe 10 is cut to an arbitrary length at the construction site, and is connected by inserting the end of the air-conditioning drain pipe 10 into a receptacle of a pipe joint (not shown) such as a socket, elbow, or cheese. The The air conditioning drain pipe 10 and the pipe joint constitute an air conditioning drain pipe. Therefore, the foamed layer 2 and the non-foamed outer layer 3 are exposed at the end face (cut surface) of the air conditioning drain pipe 10 inside the pipe joint receiving port.
Since the air-conditioning drain pipe 10 has a high closed cell ratio in the foam layer 2 and the drainage water flowing down the inside of the pipe is difficult to permeate, an adhesive is uniformly applied to the end of the air-conditioning drain pipe as in the past. The annular elastic body may not be provided inside the pipe joint.

  The outer diameter of the air conditioning drain pipe 10 is preferably, for example, 32 mm or more and 100 mm or less. The inner diameter of the air conditioning drain pipe 10 is preferably 19 mm or more and 80 mm or less, for example. The thickness of the air-conditioning drain pipe 10 including the foamed layer 2 and the non-foamed outer layer 3 is preferably 6 mm or more and 10 mm or less, for example.

The longitudinal elastic modulus of the air conditioning drain pipe 10 is preferably 400 MPa or more and 1500 MPa or less, more preferably 500 MPa or more and 1300 MPa or less, and further preferably 600 MPa or more and 1000 MPa or less.
By setting the longitudinal elastic modulus within the above numerical range, when the air conditioning drain pipe 10 receives external force, the air conditioning drain pipe 10 breaks flexibly following these external forces while suppressing deformation of bending and elongation. Can be prevented.
The longitudinal elastic modulus is also called longitudinal elastic modulus and Young's modulus, and is obtained from tensile stress and tensile strain obtained by a tensile test according to JIS K 7161-1: 2014.
The longitudinal elastic modulus can be adjusted by the degree of polymerization of the vinyl chloride resin, the expansion ratio of the foam layer 2, the thickness of each of the foam layer 2 and the non-foam outer layer 3, and the like.

<Non-foamed outer layer>
The non-foamed outer layer 3 is a non-foamed layer containing a vinyl chloride resin (A). Here, the non-foamed layer refers to a layer in which the vinyl chloride resin does not contain a foaming agent and bubbles are not formed by expansion of the foaming agent.
The vinyl chloride resin (A) may be a mixture of a vinyl chloride resin and an elastomer resin, or a graft polymer obtained by graft polymerization of a vinyl chloride resin on an elastomer resin.
The vinyl chloride resin may be polyvinyl chloride or a copolymer of a vinyl chloride monomer and another monomer copolymerizable with the vinyl chloride monomer. Examples of 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, and acrylonitrile. And the like. These may be used alone or in combination of two or more.
Examples of the elastomer resin include chlorinated polyethylene (CPE), methyl methacrylate-butadiene-styrene copolymer (MBS), and alkyl (meth) acrylate resin.
The mass ratio represented by vinyl chloride resin: elastomer resin is preferably 100: 4 to 100: 10.

  As said alkyl (meth) acrylate resin, what mainly has the alkyl (meth) acrylate monomer whose glass transition temperature of a homopolymer is less than -20 degreeC is preferable. Examples of the alkyl (meth) acrylate monomer include ethyl acrylate, n-propyl acrylate, isobutyl acrylate, n-butyl acrylate, sec-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, and n-octyl (meth) acrylate. , Isooctyl acrylate, n-decyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl acrylate, 2-acryloyloxyethyl succinic acid and the like. These may be used alone or in combination of two or more.

  The form and structure of the alkyl (meth) acrylate resin are not particularly limited. For example, the core-shell structure in which the monomer composition of the resin particle inside (core part) and the surface layer part (shell part) is different depends on the target performance. It is preferable because different functions can be provided between the core portion and the shell portion. As the alkyl (meth) acrylate monomer used for the core part, it is preferable to use one having a low glass transition temperature in view of improving the impact resistance of the molded article. For example, 2-ethylhexyl acrylate is preferably used. In the shell portion, n-butyl acrylate is preferably used from the viewpoint of improving the handling property of the alkyl (meth) acrylate resin.

  As said alkyl (meth) acrylate resin, 0.01-15 weight part of polyfunctional monomers may be added with respect to 100 weight part of said alkyl (meth) acrylate monomers. When the addition amount of the polyfunctional monomer is less than 0.01 parts by weight with respect to 100 parts by weight of the alkyl (meth) acrylate monomer, the durability of the finally obtained molded article is reduced, and 15 parts by weight. If it exceeds, the impact resistance decreases.

  The polyfunctional monomer is not particularly limited as long as it is copolymerizable with the alkyl (meth) acrylate monomer. For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6 -Polyfunctional acrylates such as hexanediol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate; polyfunctional allyl compounds such as diallyl phthalate, diallyl malate, triallyl isocyanurate An unsaturated compound such as butadiene. These may be used alone or in combination of two or more.

  The method for obtaining the alkyl (meth) acrylate resin is not particularly limited, and examples thereof include an emulsion polymerization method and a suspension polymerization method. In view of the development of impact resistance, the emulsion polymerization method is preferred. In the emulsion polymerization method, an emulsion dispersant is added for the purpose of improving the dispersion stability of the alkyl (meth) acrylate monomer in the emulsion and performing the polymerization efficiently. The emulsifying dispersant is not particularly limited, and examples thereof include anionic surfactants, nonionic surfactants, partially saponified polyvinyl alcohol, cellulose dispersants, and gelatin.

  In the emulsion polymerization method, a polymerization initiator is used. The polymerization initiator is not particularly limited, and examples thereof include potassium persulfate, ammonium persulfate, water-soluble polymerization initiators of hydrogen peroxide, organic peroxides such as benzoyl peroxide and lauroyl peroxide, azobisisobutyronitrile. And azo-based initiators. Furthermore, a pH adjuster, an antioxidant and the like may be added as necessary.

  The emulsion polymerization method is not particularly limited, and examples thereof include a batch polymerization method, a monomer dropping method, and an emulsion dropping method because of the difference in monomer addition method. The batch polymerization method includes, for example, pure water, an emulsifying dispersant, a polymerization initiator, and a mixed monomer in the jacketed polymerization reactor [the alkyl (meth) acrylate monomer + the polyfunctional monomer added as necessary]. Is added in a batch, and after sufficiently emulsifying with stirring under the conditions of oxygen removal and pressurization by a nitrogen stream, polymerization is performed by heating the inside of the vessel with a jacket.

  In the monomer dropping method, for example, pure water, an emulsifying dispersant, and a polymerization initiator are placed in a jacketed polymerization reactor, and the inside of the vessel is first heated by a jacket under the conditions of oxygen removal and pressurization under a nitrogen stream. In this method, the mixed monomer is gradually dropped by dropping a certain amount of the mixed monomer.

  In the emulsion dropping method, for example, the above-mentioned mixed monomer, emulsifying dispersant, and pure water are sufficiently emulsified by stirring to prepare an emulsified monomer in advance, and then pure water and a polymerization initiator are placed in a jacketed polymerization reactor, and nitrogen is added. In this method, polymerization is carried out by first heating the inside of the vessel with a jacket under a condition of oxygen removal and pressurization under an air stream, and then dropping the above-mentioned emulsifying monomer dropwise by a certain amount.

  Even when the alkyl (meth) acrylate resin has a core-shell structure, the formation method is not particularly limited. For example, first, a mixed monomer constituting the core portion [the alkyl (meth) acrylate monomer + necessary The above-mentioned polyfunctional monomer added according to the above), a polymerization initiator is added to an emulsified monomer prepared from pure water and an emulsifier, a polymerization reaction is performed to form resin particles in the core part, and then a mixture constituting the shell part A method of adding an emulsion monomer prepared from a monomer [the above alkyl (meth) acrylate monomer + the above-mentioned polyfunctional monomer added as necessary], pure water and an emulsifier, and graft-coating the shell part to the core part, etc. Is mentioned.

The alkyl (meth) acrylate resin thus obtained is obtained by covering the surface of the core part three-dimensionally with the shell part, and forming a copolymer constituting the shell part and a copolymer constituting the core part. Are partially covalently bonded, and the shell portion forms a three-dimensional crosslinked structure.
In the above method, the graft copolymerization of the shell part may be continuously performed in the same polymerization step as the polymerization of the core part.

  The ratio of the core part to the shell part can be adjusted by adjusting the ratio of the mixed monomer forming the core part and the mixed monomer forming the shell part in the emulsion polymerization method.

  As the vinyl chloride resin (A), the alkyl (meth) acrylate resin obtained by the above method is used, and this alkyl (meth) acrylate resin can be copolymerized with vinyl chloride or vinyl chloride and vinyl chloride. Those obtained by graft copolymerization of a vinyl chloride resin (A) comprising the above monomer are preferably used.

  The method for obtaining the vinyl chloride resin is not particularly limited, and examples thereof include an emulsion polymerization method and a suspension polymerization method. Of these, suspension polymerization is preferred. In the suspension polymerization method, the dispersion stability of the alkyl (meth) acrylate resin is improved, and graft copolymerization of vinyl chloride or a mixture of vinyl chloride and other monomers copolymerizable with vinyl chloride is efficient. For the purpose of (1), a dispersant and an oil-soluble polymerization initiator are used.

  The dispersant is not particularly limited, and examples thereof include methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, partially saponified polyvinyl acetate, gelatin, polyvinyl pyrrolidone, starch maleic anhydride-styrene copolymer, and the like. These may be used alone or in combination of two or more.

  As the oil-soluble polymerization initiator, a radical polymerization initiator is preferably used because it is advantageous for graft copolymerization. Examples of the polymerization initiator used in the present invention include t-butyl peroxypivalate, diisopropyl peroxydicarbonate, t-butyl peroxyneodecanoate, α-cumyl peroxyneodecanoate, isobutyryl peroxide, α, α ′ Organic peroxides such as bis (neodecanoylperoxy) diisopropylbenzene, 1,1,3,3-tetramethylbutylperoxyneodecanoate; 2,2-azobis-2,4-dimethyl Examples include azo compounds such as valeronitrile.

  In the above suspension polymerization method, a pH adjuster, an antioxidant and the like may be added as necessary.

  In the suspension polymerization method, specifically, for example, in a reaction vessel equipped with a stirrer and a jacket, pure water, the alkyl (meth) acrylate resin, a dispersant, an oil-soluble polymerization initiator, and as necessary. If necessary, the polymerization regulator is added, and then the air in the polymerization vessel is discharged with a vacuum pump, and further, vinyl chloride and, if necessary, other vinyl monomers are added under stirring conditions, and then the reaction vessel The inside is heated by a jacket to carry out graft copolymerization of vinyl chloride.

  Since the graft copolymerization of vinyl chloride is an exothermic reaction, the temperature in the reaction vessel can be controlled by changing the jacket temperature. After completion of the reaction, the vinyl chloride resin can be produced by removing unreacted vinyl chloride to form a slurry, followed by dehydration drying. Since the vinyl chloride resin produced by the above production method is obtained by graft copolymerization of an alkyl (meth) acrylate resin with a vinyl chloride resin (A), a vinyl chloride resin molded article having excellent impact resistance. Can be molded.

  The non-foamed outer layer 3 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 independently and 2 or more types may be used together.

The weight average molecular weight of the vinyl chloride resin (A) is preferably 37500 or more and 81000 or less, and more preferably 50000 or more and 81000 or less.
The mass average molecular weight is a value measured by gel permeation chromatography using polyethylene glycol as a standard substance.
The average polymerization degree of the vinyl chloride resin in the vinyl chloride resin (A) is preferably 600 or more and 1300 or less, more preferably 800 or more and 1300 or less, and further preferably 800 or more and 1000 or less.
The average degree of polymerization can be calculated by dividing the mass average molecular weight by the molecular weight of chloroethylene.

The thickness of the non-foamed outer layer 3 is preferably 0.6 mm or more and 1.5 mm or less, and more preferably 1.0 mm or more and 1.3 mm or less. By setting the thickness of the non-foamed outer layer 3 to be equal to or more than the above lower limit value, it can be strengthened by an external impact. By setting the thickness of the non-foamed outer layer 3 to be equal to or less than the above upper limit value, the air-conditioning drain pipe 10 can be reduced in weight. Moreover, since the thickness of the foam layer 2 can be increased, the air conditioning drain pipe 10 can be made excellent in heat insulation.
When strengthening by impact from the outside, the thickness of the non-foamed outer layer 3 is preferably 1.0 mm or greater and 5.0 mm or less, and more preferably 1.5 mm or greater and 3.5 mm or less.

  The non-foamed outer layer 3 may contain a pigment. By including the pigment, the appearance can be improved.

<Foamed layer>
The foam layer 2 is formed by foaming a resin containing the vinyl chloride resin (B) and a thermoplastic resin composition for the foam layer containing a foaming agent.
The vinyl chloride resin (B) may be a vinyl chloride resin, a mixture of a vinyl chloride resin and an elastomer resin, or a graft polymer obtained by graft polymerization of a vinyl chloride resin on an elastomer resin.
The vinyl chloride resin may be polyvinyl chloride or a copolymer of a vinyl chloride monomer and another monomer copolymerizable with the vinyl chloride monomer. Examples of 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, and acrylonitrile. And the like. These may be used alone or in combination of two or more.
Examples of the elastomer resin include chlorinated polyethylene (CPE), methyl methacrylate-butadiene-styrene copolymer (MBS), and alkyl (meth) acrylate resin.
The vinyl chloride resin (B) may be the same as or different from the vinyl chloride resin (A).
The thickness of the foam layer 2 is preferably 4.0 mm or greater and 10 mm or less.

  The foam layer 2 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 independently and 2 or more types may be used together.

The weight average molecular weight of the vinyl chloride resin (B) is preferably from 37500 to 62500, more preferably from 44000 to 56000.
The average degree of polymerization of the vinyl chloride resin in the vinyl chloride resin (B) is preferably from 600 to 1,000, more preferably from 700 to 900.

As the foaming agent, either a volatile foaming agent or a decomposable foaming agent may be used.
Examples of the volatile foaming agent include aliphatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, ethers, and ketones. Among these, examples of the aliphatic hydrocarbon include propane, butane (normal butane, isobutane), pentane (normal pentane, isopentane, etc.), and examples of the alicyclic hydrocarbon include cyclopentane, cyclohexane, and the like. Can be mentioned. Examples of the halogenated hydrocarbon include one or more of halogenated hydrocarbons such as trichlorofluoromethane, trichlorotrifluoroethane, tetrafluoroethane, chlorodifluoroethane, difluoroethane, and the like. Furthermore, examples of the ether include dimethyl ether and diethyl ether, and examples of the ketone include acetone and methyl ethyl ketone.
Examples of the decomposable foaming agent include sodium bicarbonate (sodium bicarbonate), sodium carbonate, ammonium bicarbonate, ammonium nitrite, azide compound, sodium borohydride and other inorganic foaming agents, azodicarbonamide, barium azodicarboxylate And organic foaming agents such as dinitrosopentamethylenetetramine.
Alternatively, a thermally expandable capsule in which the hydrocarbon is encapsulated in a thermoplastic resin may be used.
In addition, a gas such as carbon dioxide, nitrogen, or air may be used as the foaming agent.
These may be used independently and 2 or more types may be used together.

The foam layer 2 may contain a known stabilizer such as a lead compound (lead stabilizer), a CaZn compound (CaZn stabilizer), a tin compound (tin stabilizer) as a stabilizer. In particular, the inclusion of a stabilizer containing a tin compound makes it easy to increase the thermal stability of the resin. As the tin compound, mercapto, laurate, and malate are preferable.
The presence and content of these compounds are confirmed by inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma emission spectrometry (ICP-AES), gas chromatograph mass spectrometry (GC-MS), and the like. be able to. In the case of ICP-AES, it can be measured according to EN ISO17353: 2004.
The foam layer 2 may contain a lubricant. By including the lubricant, it becomes easy to maintain the slipperiness with the metal surface and the slipperiness between the resins. As the lubricant, ester, polyethylene and polyethylene oxide are preferable.

The expansion ratio of the foam layer 2 is 3.5 times or more, and preferably 4.0 times or more. Moreover, 8.0 times or less are preferable and 6.0 times or less are more preferable.
By setting the expansion ratio within the above range, both heat insulation and strength of the tube can be achieved. Further, by setting the expansion ratio within the above range, the air-conditioning drain pipe 10 can be reduced in weight.
The expansion ratio can be adjusted by the type or amount of resin, the type or amount of foaming agent, the production conditions, and the like.
The expansion ratio can be measured by the following method.
[Measurement method of expansion ratio]
A test piece is prepared by cutting out a circumferential direction of 10 mm or more and an axial direction of 50 mm from the air-conditioning drain pipe 10, cutting the non-foamed outer layer 3 with a milling cutter, and processing only the foamed layer 2 into a plate shape having a length of about 50 mm. . In addition, four test pieces shall be produced centering on the points equally divided into four in the inner circumferential direction.
According to JIS K 7112: 1999, the apparent density is calculated to 3 digits after the decimal point with a water displacement specific gravity measuring machine at 23 ° C. ± 2 ° C., and the expansion ratio is calculated by the following formula (1).
m = γc / γ (1)
[In the formula (1), m is the expansion ratio, γ is the apparent density (g / cm ³ ) of the foamed layer 2, and γc is the density when the foamed layer 2 is not foamed (g / cm ³ ). . ]

The closed cell ratio of the foam layer 2 is preferably 20% or more, more preferably 45% or more, still more preferably 60% or more, and particularly preferably 80% or more. The upper limit value of the closed cell ratio is not particularly limited, and is practically 95% or less, and may be 100% or 90% or less.
By setting the closed cell ratio within the above range, the heat insulation can be improved and water permeation into the foamed layer 2 can be prevented. Further, when the closed cell ratio of the foamed layer 2 is within the above numerical range, even if the thickness of the non-foamed outer layer 3 to be described later is reduced, water hardly penetrates from the outside, and the heat insulating property is unlikely to deteriorate.
The closed cell ratio can be adjusted by the type or amount of the resin, the type or amount of the foaming agent, the production conditions, and the like.
The closed cell ratio can be measured by the following method.
[Measurement method of closed cell ratio]
The air-conditioning drain pipe 10 is cut to a length of about 30 mm, cut in the circumferential direction so as to have a peripheral length of about 20 mm, and the non-foamed outer layer 3 is removed with an NT cutter as a test piece.
In accordance with JIS K 7138, the volume was measured with an air-comparing hydrometer at 23 ° C. ± 2 ° C., and in accordance with JIS K 7112: 1999, the volume obtained with a water displacement hydrometer was measured at 23 ° C. ± 2 ° C. The closed cell ratio is measured by (2).
Cc = (Va / Vaq) × 100 (2)
Wherein (2), Cc is the closed cell ratio (%), Va is the air comparison type volume (cm ^3), Vaq is water displacement method volume (cm ^3). ]

The average cell diameter of the foamed layer 2 is preferably 30 μm or more and 1000 μm or less, more preferably 40 μm or more and 700 μm or less, further preferably 50 μm or more and 400 μm or less, and particularly preferably 50 μm or more and 250 μm or less.
By setting the average cell diameter within the above range, the heat insulation can be improved and the penetration of water into the foamed layer 2 can be prevented. Even if the bubbles are not completely closed cells (closed cell rate is 100%), and the bubble wall is partly connected and water can penetrate, the average cell diameter is within the above range, and the closed cell rate is If it is in the said range, water will not osmose | permeate deep inside the foaming layer 2, and heat insulation performance will not be a problem in practical use.
The average cell diameter can be adjusted by the type or amount of the resin, the type or amount of the foaming agent, the production conditions, and the like.
The average bubble diameter can be measured by the following method.
[Measurement method of average bubble diameter]
The air-conditioning drain pipe is cut in the circumferential direction, and an annular end face of the cut air-conditioning drain pipe is photographed at a magnification of 20 using a scanning electron microscope (SEM) in accordance with JIS K 6400-1. Up to 8 straight lines (corresponding to a length of 1800 μm in the actual tube cross section) of 8 lines (2 in the vertical direction (thickness direction of the tube cross section) and 2 in the horizontal direction (circumferential direction of the tube cross section). The value obtained by dividing 1800 μm by the number of bubbles on each straight line was defined as the bubble diameter (μm). And let the average value of the bubble diameter obtained from eight straight lines be an average bubble diameter.

<Non-foamed inner layer>
As shown in FIG. 3, the air-conditioning drain pipe of the present invention may have a non-foamed inner layer 1 which is provided on the inner surface of the foamed layer 2 and is a non-foamed layer containing a vinyl chloride resin (C). . The vinyl chloride resin (C) may be a vinyl chloride resin, a mixture of a vinyl chloride resin and an elastomer resin, or a graft polymer obtained by graft polymerization of a vinyl chloride resin on an elastomer resin.
The vinyl chloride resin may be polyvinyl chloride, or may be a vinyl chloride monomer and another copolymer copolymerizable with the vinyl chloride monomer. Examples of 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, and acrylonitrile. And the like. These may be used alone or in combination of two or more.
Examples of the elastomer resin include chlorinated polyethylene (CPE), methyl methacrylate-butadiene-styrene copolymer (MBS), and alkyl (meth) acrylate resin.
The mass ratio represented by vinyl chloride resin: elastomer resin is preferably 100: 4 to 100: 10.
The vinyl chloride resin (C) may be the same as or different from the vinyl chloride resin (A).

  The non-foamed inner layer 1 may contain a thermoplastic resin other than the vinyl chloride resin (C). 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 independently and 2 or more types may be used together.

The weight average molecular weight of the vinyl chloride resin (C) is preferably from 37500 to 62500, more preferably from 50,000 to 62500.
The average degree of polymerization of the vinyl chloride resin in the vinyl chloride resin (C) is preferably from 800 to 1,000.

The thickness of the non-foamed inner layer 1 is preferably 1.0 mm or greater and 5.0 mm or less, and more preferably 1.5 mm or greater and 3.5 mm or less. By setting the thickness of the non-foamed inner layer 1 within the above numerical range, there is no fear that drain drainage flowing through the inside penetrates into the foamed layer 2, and the air-conditioning drain pipe 10 'having excellent heat insulation can be obtained.
On the other hand, when the closed cell ratio of the foam layer 2 is high, the foam layer 2 itself prevents the drain water from penetrating, so that the non-foam inner layer 1 may have a thickness of 0.6 mm to 1.5 mm. The tube 10 'can be lightened. Further, since the thickness of the foam layer 2 can be increased, the air conditioning drain pipe 10 'can be made excellent in heat insulation.

The fusion strength between the foamed layer 2 and the non-foamed inner layer 1 is preferably 1.5 MPa or more, and more preferably 2.0 MPa or more.
By making the fusion strength within the above range, it is possible to prevent the foamed layer 2 and the non-foamed inner layer 1 from being separated.
The fusion strength can be adjusted by the type or amount of resin, the type or amount of foaming agent, the production conditions, and the like.
The fusion strength can be measured by the following method.
[Measurement method of fusion strength]
A test piece is obtained by cutting the air-conditioning drain pipe 10 'into a 20 mm tube along the pipe axis.
The test piece 43 is set on the punching jig 41 of the universal testing machine 40 shown in FIG. 2 and sandwiched between the compression plates 42 under the conditions of a temperature of 23 ° C. ± 2 ° C. and a humidity of 45% to 85%. , Compression is performed at a speed of 10 mm / min ± 2 mm / min per minute in a direction perpendicular to the tube axis, and the maximum load when the fusion surface between the non-foamed inner layer 1 and the foamed layer 2 is peeled is obtained. The fusion strength is calculated in 3) and (4).
F = W / S (3)
S = 3.14 × d × L (4)
[In Formulas (3) and (4), F is the fusion strength (MPa), W is the maximum load (N), S is the fusion area (cm ² ), and d is the non-foamed inner layer average. The outer diameter (cm), and L is the test piece length (cm). ]

≪Method for manufacturing air conditioning drain pipe≫
4 and 5 are overall configuration diagrams of a manufacturing apparatus 20 for manufacturing a three-layer air-conditioning drain pipe 10 '. The manufacturing apparatus 20 includes an inner / outer layer extruder 11, a foam layer extruder 12, a mold 13, a cooling water tank 15, a take-up machine 16, and a cutting machine 17. A mold 13 is connected to the inner / outer layer extruder 11 and the foamed layer extruder 12, and a cooling water tank 15 is connected to the mold 13. 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. Further, as shown in FIGS. 4 and 5, the gas cylinder 18 and the metering pump 19 may be connected to the foam layer extruder 12.
The gas cylinder 18 and the metering pump 19 supply a gas blowing agent from the vent hole of the foam layer extruder 12.
The inner / outer layer extruder 11 melts and kneads the non-foamed layer thermoplastic resin composition forming the non-foamed inner layer 1 and the non-foamed outer layer 3 and extrudes them into the mold 13.
The foam layer extruder 12 melts and kneads the foam layer thermoplastic resin composition forming the foam layer 2 and extrudes it into the mold 13.
The mold 13 is composed of a non-cured three-layer structure from a non-foamed layer thermoplastic resin composition injected from the inner and outer layer extruder 11 and a foamed layer thermoplastic resin composition injected from the foamed layer extruder 12. The air-conditioning drain pipe 100 'is formed.
The cooling water tank 15 is provided with a tube outer surface forming tube 14 for forming an uncured air conditioning drain tube 100 ′ into a predetermined size. The uncured air conditioning drain tube 100 formed by the mold 13. It cools in the state which contacted the tube 14 for pipe | tube outer surface shaping | molding.
The take-up machine 16 receives the air-conditioning drain pipe 10 ′ cooled in the cooling water tank 15.
The cutting machine 17 cuts the air-conditioning drain pipe 10 ′ sent from the take-up machine 16 into a predetermined length.

First, the non-foamed layer thermoplastic resin composition is supplied to the inner and outer layer extruder 11 and melt-kneaded. Separately from this, 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 the 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 melt-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.

  6, the non-foamed layer thermoplastic resin composition 21 melted and kneaded by the inner and outer layer extruder 11, and the foamed layer thermoplastic resin composition 22 melted and kneaded by the foamed layer extruder 12. Are injected into the mold 13 and merged inside the mold 13 to form an uncured air-conditioning drain pipe 100 'having a three-layer structure. The uncured air-conditioning drain pipe 100 ′ is made of a non-foamed thermoplastic resin layer 31 formed from the non-foamed layer thermoplastic resin composition 21, and a foamed layer thermoplastic between the non-foamed inner layer and the non-foamed outer layer. The foamed thermoplastic resin layer 32 is formed from the resin composition 22.

  Furthermore, when the uncured air conditioning drain pipe 100 ′ having a three-layer structure is discharged from the mold 13, the resin of the foamed thermoplastic resin layer 32 is foamed. An uncured air-conditioning drain pipe 100 'is inserted into the tube outer surface forming tube 14, and the uncured air-conditioning drain pipe 100' is cooled in the cooling water tank 15 while being molded to a predetermined size, and then the air-conditioning drain pipe. 10 '. Further, the cooled air-conditioning drain pipe 10 ′ is delivered to the take-up machine 16 and sent to the cutting machine 17, where it is cut into a predetermined length.

The temperature when 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 time for molding with a mold is preferably 10 minutes or longer and 30 minutes or shorter, and more preferably 10 minutes or longer and 20 minutes or shorter.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

The components in the table are described below.
In addition, content of each component in a table | surface represents the mass part when the polyvinyl chloride of a foamed layer is 100 mass parts.
<Vinyl chloride resin (B)>
B-1: Polyvinyl chloride (degree of polymerization 800, manufactured by Tokuyama Sekisui Industry Co., Ltd., trade name “TS-800E”).
<Foaming agent>
D-1: Baking soda (manufactured by Eiwa Kasei Kogyo Co., Ltd., trade name “Selbon SC-855”).
D-2: Azodicarbonamide (manufactured by Eiwa Kasei Kogyo Co., Ltd., trade name “Binihol AC # 3”).
<Vinyl chloride resin (A) and (C)>
A-1: 5 parts by mass of MBS (trade name “B-564” manufactured by Kaneka Corporation) with respect to 100 parts by weight of polyvinyl chloride (degree of polymerization 1000, manufactured by Tokuyama Sekisui Kogyo Co., Ltd., trade name “TS-1000R”) Part, 3 parts by mass of CPE (manufactured by Showa Denko KK, trade name “Elastylene 351A”).
A-2: Polyvinyl chloride (degree of polymerization 1000, manufactured by Tokuyama Sekisui Kogyo Co., Ltd., trade name “TS-1000R”) 100 parts by mass, MBS (manufactured by Kaneka Co., Ltd., trade name “B-564”) 6. A mixture of 5 parts by mass and 3.5 parts by mass of CPE (manufactured by Showa Denko KK, trade name “Elastylene 351A”)
A-3: Polyvinyl chloride (degree of polymerization 1000, manufactured by Tokuyama Sekisui Kogyo Co., Ltd., trade name “TS-1000R”) with respect to 100 parts by mass, MBS (Kaneka Co., Ltd., trade name “B-564”) 5 masses , 1.5 parts by mass of CPE (made by Showa Denko KK, trade name “Elaslene 351A”).
A-4: Graft polymer of vinyl chloride and alkyl (meth) acrylate (polymerization degree 1200, manufactured by Tokuyama Sekisui Kogyo Co., Ltd., trade name “AG-64T”, elastomer content: 5.3 mass%).
A-5: Polyvinyl chloride (degree of polymerization 1000, manufactured by Tokuyama Sekisui Kogyo Co., Ltd., trade name “TS-1000R”).
A-6: Polyvinyl chloride (degree of polymerization 800, manufactured by Tokuyama Sekisui Industry Co., Ltd., trade name “TS-800E”).

Example 1
100 parts by mass of polyvinyl chloride B-1, 2 parts by mass of a tin-based stabilizer (trade name “STX-80”, manufactured by Daikyo Kasei Kogyo Co., Ltd.) and 2.2 parts by mass of the foaming agent D-1 were mixed. Thus, a thermoplastic resin composition for the foam layer was prepared.
The vinyl chloride resin A-1 was prepared as described above, and 100 parts by mass of the vinyl chloride resin A-1 and 2 parts by mass of a tin stabilizer (trade name “STX-80” manufactured by Daikyo Kasei Kogyo Co., Ltd.) Were mixed to prepare thermoplastic resin compositions for the inner and outer layers.
These compositions are used as an inner / outer layer extruder 11, a foam layer extruder 12, a mold 13, a cooling water tank 15 to which a tube outer surface forming tube 14 is attached, a take-up machine 16, and a cutting machine 17 shown in FIGS. Extrusion molding was performed using a manufacturing apparatus constituted by:
Specifically, the thermoplastic resin composition for the non-foamed layer was kneaded at 180 ° C. by the inner / outer layer extruder 11 and injected into the mold 13 at an extrusion rate of 45 kg / h. The thermoplastic resin composition for the foam layer was kneaded at 170 ° C. with the foam layer extruder 12 and poured into the mold 13 at 25 kg / h. As the mold 13, a mold having a product outer diameter of 89 mm and an inner diameter of 77 mm was used. The composition discharged from the mold 13 is inserted into a tube outer surface forming tube 14, cooled in a cooling water tank 15, taken up by a take-up machine 16, and then cut into a predetermined length by a cutting machine 17. A layered air-conditioning drain pipe was obtained. When the thickness of the non-foamed outer layer was measured, it was 1.0 mm.

(Examples 2 to 5, Comparative Examples 1 and 3)
A three-layer air-conditioning drain pipe was obtained in the same manner as in Example 1 except that the components described in Tables 1 and 2 were used. When the thickness of the non-foamed outer layer was measured, it was 1.0 mm.

(Comparative Example 2)
A thermoplastic resin composition for a foam layer was prepared by mixing 100 parts by mass of polyvinyl chloride B-1 and 2.2 parts by mass of foaming agent D-1.
Vinyl chloride resin A-6 was used as the thermoplastic resin composition for the inner and outer layers.
An air conditioning drain pipe was manufactured using an air conditioning drain pipe manufacturing apparatus 500 shown in FIGS.
7 and 8, the manufacturing apparatus 500 includes a first extruder 530, a second extruder 540, a mold 550, a pipe outer surface adjustment device 560, a cooling device 570, a take-up machine 580, and a cutting machine 590. The first extruder 530 and the second extruder 540 are connected to a mold 550, the mold 550 is connected to a pipe outer surface adjusting device 560, the pipe outer surface adjusting device 560 is connected to a cooling device 570, and the cooling device 570 is Connected to the take-up machine 580, the take-up machine 580 is connected to the cutting machine 590. The thermoplastic resin composition for the foam layer was kneaded at 170 ° C. by the first extruder 530 and poured into the mold 550 at an extrusion rate of 25 kg / h. Further, the thermoplastic resin composition for the non-foamed layer was kneaded at 180 ° C. by the second extruder 540 and poured into the mold 550 at an extrusion rate of 45 kg / h. As the mold 550, a mold having a product outer diameter of 89 mm and an inner diameter of 77 mm was used. As shown in FIG. 9, the mold 550 includes a first mold 551 and a crosshead die 552. The composition discharged from the mold 550 is brought into contact with the pipe outer surface adjustment device 560. At this time, the temperature of the outer surface decreases, and a coating layer 230 is formed as the outermost layer as shown in FIG. For air-conditioning drain having a three-layer structure comprising a non-foamed inner layer 210, a foamed layer 220, and a coating layer 230 after being cooled in the cooling device 570, taken up by a take-up machine 580, and cut into a predetermined length by a cutting machine 590. Got the tube. It was 1.0 mm when the thickness of the coating layer was measured.

  About the obtained pipe | tube for air-conditioning drains, the expansion ratio, impact resistance, fusion strength, pencil hardness, and a longitudinal elastic modulus were measured in the following procedures, respectively.

[Measurement of foaming ratio]
Cut out 10 mm or more in the circumferential direction and 50 mm in the axial direction from the air-conditioning drain pipe, cut the non-foamed inner layer and the non-foamed outer layer with a mill, and processed only the foamed layer into a plate shape with a length of about 50 mm as a test piece. did. Four test pieces were created around the points equally divided into four in the inner circumferential direction.
According to JIS K 7112: 1999, the apparent density was calculated to 3 digits after the decimal point with a water displacement specific gravity measuring machine at 23 ° C. ± 2 ° C., and the expansion ratio was calculated by the following formula (1).
m = γc / γ (1)
[In the formula (1), m is the expansion ratio, γ is the apparent density (g / cm ³ ) of the foamed layer, and γc is the density (g / cm ³ ) of the foamed layer when not foamed. ]
The obtained results are shown in Tables 1 and 2.

[Measurement of impact resistance]
A plus driver (100 g) was dropped vertically on the air conditioning drain pipe, and the height at which the air conditioning drain pipe was cracked was measured.
Specifically, a Phillips screwdriver was dropped vertically onto the air conditioning drain pipe from a predetermined height, and a water pressure of 0.06 MPa was applied to the inside of the air conditioning drain pipe for 1 minute to confirm the presence or absence of water leakage. The height at which the Phillips screwdriver was dropped when water leakage was confirmed was measured.
The obtained results are shown in Tables 1 and 2.

[Measurement of fusion strength]
A test piece was prepared by cutting a tube for air-conditioning drain into a 20 mm tube along the tube axis.
Under the conditions of a temperature of 23 ° C. ± 2 ° C. and a humidity of 45% to 85%, the test piece 43 is set on the punching jig 41 of the universal testing machine 40 shown in FIG. Compressed at a rate of 10 mm / min ± 2 mm / min per minute in the direction perpendicular to the tube axis, and determined the maximum load when the fusion surface between the non-foamed inner layer and the foamed layer peels, and the following formula (3) and The fusion strength was calculated in (4).
F = W / S (3)
S = 3.14 × d × L (4)
[In Formulas (3) and (4), F is the fusion strength (MPa), W is the maximum load (N), S is the fusion area (cm ² ), and d is the non-foamed inner layer average. The outer diameter (cm), and L is the test piece length (cm). ]
The obtained results are shown in Tables 1 and 2.

[Measurement of pencil hardness]
According to JIS K 5600-5-4, the pencil hardness of the non-foamed outer layer was measured with a pencil hardness tester (054 manufactured by Allgood) having a load of 750 g and a pencil angle of 45 °.
The obtained results are shown in Tables 1 and 2. The code | symbol in a table | surface represents the hardness symbol of the pencil prescribed | regulated to JISS6006.

[Measurement of longitudinal elastic modulus]
In accordance with JIS K 7161-1: 2014, a test piece was prepared along the tube axis, and the longitudinal elastic modulus at 15 ° C. was measured.
The obtained results are shown in Tables 1 and 2.

As shown in Tables 1 and 2, it was found that the air conditioning drain pipes of Examples 1 to 5 were resistant to external impacts.
It was found that Comparative Examples 1 to 3 using polyvinyl chloride instead of the vinyl chloride resin (A) are likely to be cracked by an external impact.

DESCRIPTION OF SYMBOLS 1 Non-foaming inner layer 2 Foaming layer 3 Non-foaming outer layer 10 Air-conditioning drain pipe 10 'Air-conditioning drain pipe

Claims (2)

A cylindrical foam layer containing a vinyl chloride resin (B);
A non-foamed outer layer provided on the outer surface of the foamed layer and comprising a vinyl chloride resin (A),
The foaming ratio of the foamed layer is 3.5 times or more,
The air-conditioning drain pipe, wherein the vinyl chloride resin (A) is a mixture of a vinyl chloride resin and an elastomer resin, or a graft polymer obtained by graft polymerization of an elastomer resin to a vinyl chloride resin.   The air-conditioning drain pipe according to claim 1, wherein an average polymerization degree of the vinyl chloride resin contained in the vinyl chloride resin (A) is 800 or more and 1000 or less.

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