JPH069917B2 - 2-layer synthetic resin tube - Google Patents

Description

TECHNICAL FIELD The present invention relates to a two-layer synthetic tube for transporting water, pesticides and other liquids.

(Prior Art) Conventionally, a two-layer type synthetic resin tube made of two different layers made of different materials and formed into one body has been known.
In particular, in recent years, it has been noted that fluororesins have excellent heat resistance and chemical resistance, and urethane resins have excellent rubber elasticity, mechanical properties, oil resistance, solvent resistance, etc. Although it is remarkable, it would be desirable to develop a practical two-layer tube that has both of these excellent properties and is stable and robust.

(Problems to be Solved by the Invention) In the conventional two-layer tube made of the above-mentioned two kinds of synthetic resins, the inner and outer molding layers are simply bonded to each other through a synthetic resin adhesive, but It was extremely difficult to bond the inner and outer layers to. That is, since the fluororesin is non-adhesive and non-polar, when producing a one-piece molded tube composed of two layers of inner and outer layers of the fluororesin and urethane resin, simply press the urethane resin and other various synthetic resin adhesives. The two-layer type tube obtained by molding and attempting mutual adhesion of the inner and outer layers can be obtained as a stable and practical two-layer type tube because the inner and outer layers are easily delaminated by hand pulling force. I couldn't do it. In practice, even if the bonding surface of the fluororesin molded tube and the urethane resin molded tube or both bonding surfaces are etched by chemical or physical means to increase the bonding surface area, However, it was not possible to eliminate the drawback of easy peeling, because strong mutual adhesion suitable for the above was not obtained.

(Means for Solving Problems) The present invention provides a stable and robust structure in which an inner layer tube made of a fluororesin and an outer layer tube made of a urethane resin, which cannot be adhered by such a conventional adhering means, are firmly bonded. The present invention provides a practically two-layer synthetic resin tube in which the joint surface of the inner layer tube made of fluororesin and the joint surface of the outer layer tube made of urethane resin are used as the inner layer tube. The joint surface where the mixed inorganic filler is exposed on the surface and the joint surface where the silane coupling agent chemically bound to the outer layer tube is provided on the surface are respectively formed, and the inner and outer joint surfaces are joined by extrusion molding. It is formed by wearing one body.

(Example) The Example of this invention is described based on an accompanying drawing.

The drawing schematically shows the two-layer synthetic resin tube of the present invention, in which (1) is an inner tube made of fluororesin,
(2) shows an outer layer tube made of urethane resin firmly bound to the outer peripheral surface thereof. According to the present invention, the mutual joint surfaces of the double-layered tubes (1) and (2) are configured as follows. That is, the joint surface of the fluororesin inner layer tube (1) is a joint with a myriad of dispersed powder inorganic fillers (3) exposed to the outer peripheral joint surface among the myriad of inorganic fillers (3) mixed therein. The joint surface of the urethane resin outer layer tube (2) is chemically bonded to these exposed inorganic fillers at one end and chemically bonded to the inner peripheral joint surface of the urethane resin outer layer tube (2) at the other end. Combined Silane Coupling Agent (4)
Since it has a joint surface with a joint, it is a stable, robust and practical two-layer synthetic resin tube in which the inner and outer layer tubes (1) and (2) are chemically bonded to each other extremely strongly by the joining of these joint surfaces. It is configured in. The two-layer synthetic resin tube was tested for its peel strength by applying a considerable tensile peeling force between the two layers, but no peeling was observed. Further, the silane coupling agent (4) on the surface of the urethane resin tube (2) was not separated from the surface. Thus, the two-layer synthetic resin tube of the present invention is flexible and has high flex resistance, and chemical resistance, heat resistance, flexibility, mechanical properties, etc. capable of exhibiting the excellent characteristics of both resins. As a practical product of a two-layer synthetic resin tube that is excellent in all of the above, it is a good hose that can carry various fluids such as agricultural chemicals and other chemical liquids depending on the application and has a long service life. Can be used as

Next, the two-layer synthetic resin tube shown in the above embodiment will be described in more detail.

It is sufficient for the fluororesin to be one that sufficiently satisfies the requirements for a thermoplastic resin, and since there is a step of mixing an inorganic filler with this, one that is easy to mix, that is, has good flow characteristics is preferable. Examples thereof include polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-hexafluoropropylene (TEP), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), tetrafluoroethylene-ethylene (ETFE), polyvinylidene fluoride ( PVDF) and the like, but ETFE and PCTFE are particularly preferable.

As the inorganic filler mixed in the fluororesin, silica, silicas such as colloidal silica, kaolin, mica, talc, calcium silicate, silicates such as aluminum silicate, iron oxide, alumina, metal oxides such as aluminum oxide. One or more inorganic fillers selected from the desired fine powders of metals, metals such as aluminum and copper are selected and used. The addition amount of these inorganic fillers to the fluororesin is preferably in the range of 1 to 10 parts with respect to 100 parts of the fluororesin, but is not limited to this range.

As the urethane resin, a thermoplastic resin, generally,
i) adipic acid-based polyester polyol composed of adipic acid and glycol, ii) caprolactone-based polyester polyol obtained by ring-opening ε-caprolactone, or ii
i) A type in which an organic diisocyanate is addition-polymerized to an ether-based polyol formed by ring-opening a cyclic ether such as THF. When Y of the silane coupling agent YRSiX ₃ is an NH ₂ group, it is compatible with this. Use a system that reacts,
From this point of view, those containing residual NCO groups are more suitable, and any commercially available product can be used.

The silane coupling agent that is chemically bonded to the reactive group of the inorganic filler and the reactive group of the urethane resin is represented by the general formula YRSiX ₃ . Mushroom Y is NH ₂ , HS And the like, and X is a reactive group such as (OCH ₂ CH ₃ ) ₃ (OC ₃ ) ₃ . If it has an NH ₂ group as a reactive group, it will bond with a urethane resin. It is easy to be compatible with each other and further to be compatible or react with the residual NCO group of the urethane resin, so that a surface to be bonded with a silane coupling agent having a chemically resistant bond with a one-body bond is obtained on the surface of the urethane resin. It is possible and advantageous. For example, γ-aminopropyltriethoxysilane (NH ₂ CH ₂ CH ₂ CH ₂ Si (O
CH) ₃ , N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane (NH ₂ CH ₂ CH ₂ NHCH ₂ Si (OCH)
₃ , γ-ureidopropylethoxysilane (NH ₂ CONHCH
_{2 CH 2 Si (OCH 2 CH} 3) 3 and the like.

The amount of the silane coupling agent added to the urethane resin is generally 0.5 to 10% by weight based on the total amount of the urethane resin.
Is preferable, and 1 to 5% by weight is optimum.

The silane coupling agent is mixed into the entire urethane resin at the time of extrusion molding and a part of the silane coupling agent is evenly exposed on the surface of the urethane resin, or the silane coupling agent is applied to the surface of the molded tube so that the surface of the urethane resin tube is covered. It is formed.

Next, a preferred specific example of producing the two-layer synthetic resin tube of the present invention in which the fluororesin is the inner layer and the urethane resin is the outer layer will be described.

Specific Example 100 kg of fluororesin (copolymer ETFE of tetrafluoroethylene and ethylene) and 5 kg of aluminum silicate powder were blended in a twin-screw extruder at a temperature of 330 to 350 ° C. to form pellets. The aluminum silicate-containing fluororesin pellets thus obtained were molded by a 30 mmφ single screw extruder to prepare a tube having an inner diameter of 1 mm and an outer diameter of 1.5 mm.

On the other hand, thermoplastic urethane resin pellets (Pandex-
5067 (manufactured by Dainippon Ink and Chemicals Inc.) and 5 kg of a silane coupling agent (γ-aminopropyltriethoxysilane) are mixed in a tumbler, and uniformly adhered to the surface of the thermoplastic urethane resin pellets, and heat treated in an electric furnace at 100 ° C for 2 hours. did. Next, an outer layer tube having a thickness of 1.5 mm is formed by extrusion coating a urethane resin in which the silane coupling agent is chemically bonded to the outer peripheral surface of the extruded tube made of the aluminum silicate-containing fluororesin as an inner layer. Coated continuously so that the overall inner diameter is 1
A two-layer synthetic resin tube having an outer diameter of 3 mm was manufactured.

For comparison, a conventional two-layer tube was prepared in the same manner as above, using a conventional fluororesin pellet without addition of an inorganic filler and a conventional urethane resin pellet to which a silane coupling agent was not attached.

When the two-layer synthetic resin tube of the present invention described above and the two-layer synthetic resin tube of the conventional example described above were used with a jig to manually apply a tensile force for peeling between the layers, the product of the present invention was completely peeled off. The conventional product was easily peeled off, whereas it was not.

(Effects of the Invention) As described above, according to the present invention, in practical application of a two-layer tube composed of a fluororesin inner layer tube and a urethane resin outer layer tube, innumerable inorganic fillers are exposed on the joint surface of the fluororesin inner layer tube. Since the joint surface of the urethane resin outer layer tube is the joint surface to which the silane coupling agent is attached in a chemically bonded state, the inner and outer layer tubes are chemically bonded by the inorganic filler and the silane coupling agent. Is firmly settled, and since the silane coupling agent is chemically anchored to the outer layer tube, the silane coupling agent does not peel off or separate from the outer layer tube, and as a whole, bends. A two-layer synthetic resin tube suitable for practical use that is stable and solid without separation is obtained. It has the effect of providing a durable hose for various uses that can be sufficiently exerted.

[Brief description of drawings]

The drawing shows a cross-sectional view of a portion of an example product embodying the invention. (1)… Inner layer tube (2)… Outer layer tube (3)… Inorganic filler (4)… Silane coupling agent

Claims (1)

[Claims] 1. A joining method in which a joining surface of an inner layer tube made of a fluororesin and a joining surface of an outer layer tube made of a urethane resin are exposed on the surface of an inorganic filler mixed in the inner tube. A two-layer system in which a silane coupling agent chemically bonded to the outer layer tube is formed on the surface and a bonding surface provided on the surface, and the inner and outer bonding surfaces are bonded by extrusion molding to form one body Synthetic resin tube.