JPS5997377A - Thermoplastic resin multilayer tubular body for cooler hose - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic resin multilayer tubular body for a cooler hose.

(Background) Tubular bodies made of polyamide resin have excellent mechanical strength, chemical properties such as chemical resistance, and resistance to Freon gas permeation, making them useful as inner tube materials for cooler hoses. However, its drawbacks include insufficient flexibility and moisture resistance.

Therefore, as a means to improve the flexibility of polyamide resin tubular bodies, attempts have been made to incorporate a plasticizer into the material resin. However, this method has the disadvantage that the plasticizer is eluted at high temperatures, and flexibility is often not always sufficient. Furthermore, even if a certain degree of flexibility improvement can be expected by adding a plasticizer, the impact resistance of the tubular body at low temperatures decreases. Furthermore, since the tubular body made of polyamide resin has high water vapor permeability, when used as a cooler hose material, the cooling efficiency is likely to decrease due to freezing of water (the above method is therefore not preferred).

Therefore, the present inventors have improved the above-mentioned drawbacks to satisfy mechanical strength, chemical properties, etc., as well as impact resistance at low humidity, and to have a balance between flexibility, Freon gas permeability, and moisture resistance. As a result of studies aimed at obtaining a thermoplastic resin tubular body for a cooler hose, it was discovered that a multilayer tubular body made of a certain specific resin in addition to a polyamide resin met the above objective.

That is, it has been found that the above object can be achieved by forming a thermoplastic multilayer tubular body consisting of at least three layers: a polyamide resin layer, a polyolefin resin layer, and a condensed polymer flexible resin layer.

The structure of the tubular body of the present invention will be specifically described below.

The polyamide resin used in the present invention is nylon 11
, nylon 12, nylon 610, nylon 612, nylon 6, nylon 66, etc., or copolymerized polyamide resins of these with each other. It is also possible to use a blend of seeds within a range that does not significantly impair the properties of the polyamide.

Among these, polyamide resins with relatively low amide group concentration, such as nylon 11 and nylon 12, are preferred from the viewpoint of flexibility and low-temperature impact resistance, and nylon 6, nylon 66, and their copolymer polyamide resins are highly resistant to Freon gas. This is particularly effective in terms of transparency.

The polyolefin resin used in the present invention is one selected from low, medium and high density polyethylene, ethyl V-prodelene copolymer, polypropylene, ethylene-vinyl acetate copolymer, and modified polyolefin. The modified polyolefin has a comonomer component of ethylene and/or propylene of 0.1 to 10
It refers to a copolymer obtained by copolymerizing or graft copolymerizing Morch's unsaturated acid or its derivatives, and examples of the unsaturated carboxylic acid as a copolymer component include acrylic acid, methacrylic acid, maleic acid, and fumaric acid. Examples include unsaturated monomers such as acids, dicarboxylic acids, or amides, esters, metal salt compounds, and acid anhydrides thereof.

These polyolefin resins are particularly excellent in terms of moisture resistance, but low- and medium-density polyethylene are preferred in terms of flexibility and low-temperature impact resistance, and polypropylene and high-density polyethylene are preferred in terms of heat resistance. The use of modified polyolefins is particularly effective in improving the adhesive strength between layers.

The condensation polymer-based flexible resin used in the present invention is at least one selected from polyester amide resins, polyether ester amide resins, polyether ester resins, copolymerized polynisder resins, and thermoplastic polyurethane resins.

Polynisderamide resin is a resin obtained by polycondensing dicarboxylic acid and low-molecular-weight diol, which are polyester-forming components, and dicarboxylic acid and ω-amino acids, ω-lactams, and/or diamines, which are polyamide-forming components. The polyether ester amide resin is a resin obtained by polycondensing a polymeric diol, the above-mentioned polyester-forming component, or only a dicarboxylic acid, which is one of the components, and the above-mentioned polyamide-forming component, Polyether ester resin is a resin obtained by polycondensing the above-mentioned polyester-forming component and the above-mentioned polymeric diol, and copolymerized polynisder resin has terephthalic acid as a dicarboxylic acid as a main component, and other A resin obtained by polycondensing polyester-forming components containing dicarboxylic acids.

Examples of the dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid,
Alicyclic dicarboxylic acids such as diphenyl/l/-4,4'-dicarboxylic acid, diphenoquinethanedicarboxylic acid, 6-sulfoisophthalic acid, 1,4-cyclohexanedicarboxylic acid, and synchlohexytv-4,4'-dicarboxylic acid. Mention may be made of acids and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, dodecanoic acid. In particular, dicarboxylic acids such as terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, sebacic acid, and dodecandioic acid are preferably used from the viewpoint of polymerizability, color tone, and physical properties of the polymer.

The low molecular weight diols include ethylene glyco-μ,
trimethylene glycol, 1,4-butanedio-〃, pentamethylene glycol, hexamethylene glycol,
Neopentyl glycol, decamethylene glycol, diethylene glycol, triethylene glycol! , fatty 1M diols such as propylene glyco-μ, alicyclic di-p,quinrylene glycols such as 1,4-cyclohexane dimetatool, bis(p-hydroquine)diphenyl, bis(p-hydroxyphenyl)globannat f) Examples include diols containing aromatic groups.

, as the ω-amino acid, ω-aminocaproic acid, ω
-aminoundecanoic acid 1. -Aminododecanoic acid, and ω-lactams include ε-caprolactam and ω-laurolactam.

M cyamines include aliphatic diamines such as hexamethylene diamine, undecamethylene diamine, and dodecamethidine diamine, bis-(p-aminocyclohexy)V
) There are alicyclic cyamines such as methane and aromatic diamines such as xylylene diamine.

The polymeric diols include polyethylene glycol, poly(1,2- and 1,3-propylene oxide) glycol, poly(tethomethylene oxide) glycol-p1
Poly(ethylene oxide) glyco-μ such as a copolymer of ethyl V oxide and propylene oxide and a copolymer of ethylenediamine and tetrohydrofuran are mentioned.

Thermoplastic polyurethane is a Glock copolymer obtained by polycondensing a bifunctional polyol component, a glycol component, and a diisocyanate component.
Examples include polybutylene adipate, polyhexamethylene adipate, polytetramethylene sepacate, polyether type polytetramethylene glycol, polyethylene glycol, capro type polycaprolactone, polycarbonate type polyhexamethylene carbonate, and the like.

Examples of glycol components include ethylene glycol, butanedio-μ, 1,6-hexanediol, bishydroxyethoxybenzene, and the like. ethylene glyco-1
In some cases, other amines such as hydrazine, ethylene diamine, and propylene diamine are used in place of the salt component.

Examples of the diisocyanate component include 4-4'-diphenylmethane diisocyanate, 4-4'-dicyclohexylmethane diisoyanate, isophorone diisocyanate, and naphthalene diisonate. These condensation polymer-based flexible resins are inherently excellent in flexibility, and when formed into a laminated layer structure with the polyamide resin and polyolefin resin, they contribute to improving the flexibility of the tubular body. In order to improve the flexibility of the tubular body for a cooler hose of the invention, the bending elastic modulus at room temperature is usually 50,001! It is particularly preferable to use one having a value of less than g/cJ (ASTM D790).

It is preferable to add 5 to 40% by weight of the above-mentioned modified polyolefin to these condensation polymer-based flexible resins in order to improve adhesion.

The layer structure of the polyamide resin, polyolefin resin, and condensation polymer flexible resin in the multilayer tubular body of the present invention can be freely selected, and may be any of the outer layer, inner layer, and intermediate layer, but usually the outer layer is It is preferable that the flexible resin is a condensation polymer, the inner layer is a polyamide resin, and the intermediate layer is a polyolefin resin.

The number of laminated layers is 5 or more, and may naturally be 4 or more.

Furthermore, the thickness structure of the laminated layers can be varied depending on various required properties such as flexibility, resistance to Freon gas permeability, impact resistance, mechanical strength, and economic efficiency.

Generally, the thickness of one type of resin layer is 1 to 98% of the total thickness, preferably 3 to 94 inches.

However, if the thickness of each resin layer is less than 1 inch, the inherent characteristics of each resin will deteriorate, which is not preferable.

The method for manufacturing the multilayer tubular body of the present invention is a common coextrusion method. For example, in the case of a five-layer tubular body, the above six types of resins are separately fed to three extruders, and these three types of molten resins are separately fed. The extruded streams are pressure-supplied into a common die to form annular streams, and then merged in five dies to form a three-layer tubular body, which is then co-extruded out of the die to perform normal sizing. Shaped to the specified dimensions by cooling method, after cooling and solidifying,
It can be obtained by applying it to a collection machine. In this case, the inside of the extruder and gouer plasticizes and extrudes the resin, so it is necessary to maintain a temperature higher than the melting temperature of the resin.Especially in the die where flows from separate extruders join together, the melting temperature is generally The temperature of the high temperature resin is maintained.

Note that the method for manufacturing the multilayer tubular body of the present invention is not limited to the coextrusion method. A method of forming a multilayer tubular body may also be used.

The thus obtained multilayer tubular body of the present invention has excellent mechanical properties such as strength, chemical properties such as chemical resistance, and has excellent balance in flexibility, Freon gas permeability, impact resistance at low temperatures, etc. It is useful as an inner tube for cooler hoses.

The present invention will be explained in further detail by giving examples below.

Examples 1 to 6, Comparative Examples 1 to 3 Three extruders were used, and one extruder was filled with nylon 6 (Toshiki CM1041) or nylon 11 (Toshikisu).
v Sun BIiiiSNOTL) and 25 each.
The inner layer was formed by extrusion at 0-260°C or 210-220°C into a circular flow in a die. In addition, one extruder is equipped with high-density polyethylene (Mitsui Toatsu Chemical Co., Ltd. Hi-ZEX 3000B), polypropylene (Mitsui Toatsu Chemical Co., Ltd. Mitsui Norpren BFiB-G), low-density polyethylene (Sumitomo Chemical Co., Ltd. Sumikase yF101-3), or modified polyolefin. (Mitsui Petrochemical ■Atmar QB31
0) and extruded at 190 to 210°C to form an intermediate layer.

Furthermore, in one extruder, the weight ratio of nylon 11/PBD obtained by polymerizing polyether ester amide resin (ATO@P]1iBAX5533SNOO) or undecanoic acid, 1,4 gutanediol, and dodecanedioic acid was 7.
0/30% polyester rareamide resin, resin or polyether ester resin (Toyo Grodakku High)
v5557) or dimethyl terephthalate, 1,4
The weight ratio of PBTiPBD obtained by polymerizing butanediol, teVfuglic acid and dodecanedioic acid is 8072.
0% copolymerized polyester or thermoplastic polyurethane resin (8 pieces of elastone ■ Ewostran B 598
PNAT) and 170 to 240 tons each.
The outer layer was formed by extrusion at a suitable temperature within the range of ::.

The mixture of these three layers is extruded from a die, cooled while sizing in a vacuum tank, and a first layer with an outer diameter of 8 gates, an inner diameter of 6 gates, and a thickness ratio of the outer layer, middle layer, and inner layer of 80:10:10% is produced. A five-layer tubular body having the configuration shown in the table was molded.

On the other hand, as a comparative example, nylon 6 single layer (0M1041)
and unplasticized nylon 12 single layer (Toshi Rilsan AKS
NOTL) and plasticized nylon 12 single layer (Toshi Rilsan AF! SNOP40'T'L) outer diameter 811#
A tubular body with an inner diameter of 6 mm was molded.

Table 1 shows the results of evaluating the physical properties of these various tubular bodies.

In addition, the flexibility of the tube was measured by measuring the load required when both ends of a tubular body cut into a length of 20 cm were bent to the minimum bending radius, and converting it into stress, which was used as a measure of flexibility.

The impact strength was determined by placing 10 tubular bodies cut into 8 cm long squares on a flat surface in an atmosphere of -20°C, and applying a weight of 5.53 kg.
A weight with an energy of m 2 was dropped from a flat surface to a distance of 1.5 times the tube wall thickness, the number of broken pieces was determined, and the number was expressed as the ratio of the number of broken pieces to the number of tests.

Freon 12 gas permeation test was carried out using 7 Leon 12 Ganu in a tubular body cut into 50 cm length at 0.6 ± 0 per i cA.
．． 1gr was sealed and left in an air constant temperature bath at 60°C for 96 hours, and after 24 hours of standing, the change in weight was measured and the permeation amount (gr/In/72hr) was calculated.

In the moisture permeation test, dried molecular sieves were sealed in a tubular body cut into 60 mm length, with an inner volume of 70 mm, and the temperature was 50 mm.
℃ and a humidity of 90 degrees or more in a constant temperature and humidity chamber (leave it for 240 hours, measure the weight change, and determine the excess amount (gr/m/24
0hr) was calculated.

As is clear from Table 1, the tubular body of the present invention has both flexibility and impact resistance at low temperatures, and is resistant to Freon 12.
It has excellent gas permeability and water permeability resistance, and is found to be useful as a tube for cooler hoses.

Claims (1)

[Claims] A thermoplastic resin multilayer tubular body for a cooler hose comprising at least three layers: a polyamide resin layer, a polyolefin resin layer, and a condensed polymer flexible resin layer.