JP5031688B2 - Synthetic resin flexible tube - Google Patents

Description

The present invention relates to a flexible synthetic resin tube having an inner surface formed of a thermoplastic polyurethane resin.

Conventionally, a synthetic resin flexible tube in which an inner surface is formed of a thermoplastic polyurethane resin and an outer surface is formed of a soft vinyl chloride resin and both are integrated by heat fusion to improve wear resistance is described in Patent Document 1. Yes. In addition, a synthetic resin flexible tube in which the inner surface is made of a polyether-based thermoplastic polyurethane resin, the outer surface is a soft vinyl chloride resin, and the inner surface and the outer surface are bonded and integrated using a blended resin is disclosed in Patent Literature. 2.
Japanese Utility Model Publication No. 49-7939 Japanese Patent Laid-Open No. 10-160062

In addition, when powder such as slaked lime or activated charcoal having the property of adsorbing fine particles is circulated inside the synthetic resin flexible tube, it is added to the inner surface of the thermoplastic polyurethane resin and the outer surface of the flexible polyvinyl chloride resin. As a result, plasticizers such as phthalate esters have a high migration property, which causes the phenomenon that they are extracted to the outside along with the transported goods, which reduces the volume of the hose, shortens the hose, and shortens the hose length. Problem occurred. In order to avoid these problems, it is known that it is effective to add a non-migrating plasticizer such as a polyester plasticizer to the hose outer layer made of a soft vinyl chloride resin.

However, the adhesion between the polyether-based thermoplastic polyurethane resin and the soft vinyl chloride resin is poor, and even with the technique described in Patent Document 2, the adhesion may not be sufficiently obtained. In particular, when soft vinyl chloride resin is plasticized with a non-migrating plasticizer in an attempt to solve the problem of hose shrinkage due to powder transfer, the adhesion with the polyether-based thermoplastic polyurethane resin is greatly deteriorated. Even if these resins are blended, they cannot be bonded well, and there is a risk of causing problems in the strength and durability of the hose, such as peeling off the inner layer and the outer layer of the hose.

Therefore, the present invention forms the outer layer without impairing the excellent mechanical strength, flexibility, elasticity, abrasion resistance, hydrolysis resistance and other properties of the polyether thermoplastic polyurethane resin of the inner layer. It is an object of the present invention to provide a synthetic resin flexible tube that can be firmly bonded to a soft vinyl chloride resin.

As a result of intensive studies, the inventor has found that when the inner layer and the outer layer are bonded together via an adhesive intermediate resin made of a polyester-based thermoplastic polyurethane resin, they can be firmly bonded to each other, thereby completing the present invention.

In the present invention, an inner layer is formed of a polyether-based thermoplastic polyurethane resin, and this inner layer is bonded and integrated with an outer layer made of a soft vinyl chloride resin through an adhesive intermediate resin layer made of a polyester-based thermoplastic polyurethane resin. It is the synthetic resin flexible tube characterized by having been made.

In the present invention, a non-migrating plasticizer may be added to the soft vinyl chloride resin of the outer layer (Claim 2), and no plasticizer may be added to the inner layer or the intermediate layer (Claim 3). , Claim 4).

According to the present invention, a synthetic resin flexible material in which a hose inner layer made of a polyether-based thermoplastic polyurethane resin excellent in abrasion resistance, flexibility, hydrolysis resistance, and the like is firmly bonded and integrated with a vinyl chloride resin of an outer hose layer. A tube is obtained.

Further, as a preferred embodiment of the present invention, when a non-migrating plasticizer is added to the soft vinyl chloride resin of the outer layer (Claim 2), or when no plasticizer is added to the inner layer or the intermediate layer (Claim) Item 3 and Item 4) also have the effect of solving the problem that the length of the hose is shortened due to the plasticizer being taken away by the powder conveyed into the hose.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention, which is made of a polyester-based thermoplastic polyurethane resin on the inner surface of an outer layer 9 made of a soft vinyl chloride resin in which a spiral reinforcing core 10 made of a hard vinyl chloride resin is embedded in the layer. A synthetic resin flexible tube 6 is constructed by bonding and integrating an inner layer 7 made of a polyether-based thermoplastic polyurethane resin via an adhesive intermediate resin layer 8.

The tube wall of the synthetic resin flexible tube 6 has a laminated structure of an inner layer 7, an adhesive intermediate resin layer 8 and an outer layer 9, and the inner layer 7, the adhesive intermediate resin layer 8 and the outer layer 9 are heat-sealed to each other. ing.

The polyether-based thermoplastic polyurethane resin forming the inner layer 7 is distinguished by the type of polyol raw material used for the polyurethane soft segment, and is a polyether-type thermoplastic polyurethane resin in which a polyether polyol is used ( TPU), but also includes those obtained by appropriately blending thermoplastic resins such as polyvinyl chloride, polyester, polyamide, etc. within a range that does not greatly change their properties.

The polyether-based thermoplastic polyurethane resin forming the inner layer 7 can be used without adding a plasticizer. For example, Pelecene (registered trademark) 2103 manufactured by Dow Chemical Company or Pandex (registered trademark) T8375 manufactured by DIC Bayer Polymer Co., Ltd. can be used. In order to prevent removal of the plasticizer by the powder conveyed through the hose and shortening of the hose length, it is preferable not to add a plasticizer. It is also a preferred embodiment to add a non-migrating plasticizer such as a polyester plasticizer.

The polyester-based thermoplastic polyurethane resin forming the adhesive intermediate resin layer 8 is distinguished from the type of polyol raw material used in the polyurethane soft segment, and is a polyester-type thermoplastic polyurethane resin in which the polyester polyol is used. Although it indicates (TPU), it also includes those obtained by appropriately blending thermoplastic resins such as polyvinyl chloride, polyester, polyamide and the like within a range that does not greatly change their properties.

The polyester-based thermoplastic polyurethane resin forming the adhesive intermediate resin layer 8 can be used without adding a plasticizer. For example, E660MZA manufactured by Japan Miractolan Co., Ltd., Elastollan (registered trademark) C70A, C80A, ET680 manufactured by BASF Japan Co., Ltd., etc. can be used. In order to prevent removal of the plasticizer by the powder conveyed through the hose and shortening of the hose length, it is preferable not to add a plasticizer. It is also a preferred embodiment to add a non-migrating plasticizer such as a polyester plasticizer.

When a polyester-based thermoplastic polyurethane resin using polyester polyol is exposed to warm water, saturated steam, etc. for a long time, the ester bond is cleaved by hydrolysis and cannot be restored. As a result, the physical properties are lowered. The polyether-based thermoplastic polyurethane resin that forms No. 7 is much more resistant to hydrolysis because it has a different chemical structure, and the present invention relates to specific types of these thermoplastic polyurethane resins. It is selected and used in the inner layer of a synthetic resin flexible tube to exhibit a wide range of applications without deteriorating the excellent properties of the thermoplastic polyurethane resin. Further, even when a polyester thermoplastic polyurethane resin having poor hydrolyzability is used for the adhesive intermediate layer 8, the intermediate layer 8 is not directly exposed to warm water or saturated water vapor. The low hydrolysis resistance can be compensated.

The soft vinyl chloride resin forming the outer layer 9 is formed by adding a non-migrating plasticizer in the present embodiment. In order to prevent the plasticizer from being taken away by the powder, the plasticization of the soft vinyl chloride resin is performed without adding a migratory plasticizer such as a phthalate ester plasticizer (DOP or the like). It is preferable. The fact that no migratory plasticizer is added here means that a plasticizer having excellent non-migratory properties such as a polyester plasticizer is used without using a general-purpose plasticizer having a large migratory property such as the phthalate ester type. In this case, it means the case of so-called internal plasticization by copolymerizing a higher alkyl vinyl derivative or the like with vinyl chloride and the case of plasticizing by so-called polymer blending by adding a modifying polymer to vinyl chloride. As the polyester plasticizer, it is particularly preferable to use a polyester plasticizer having a high molecular weight (molecular weight 600 to 8000) and a small absolute migration amount. For example, the outer layer 9 may be obtained by adding 90 parts by weight of a polyester plasticizer (for example, Polysizer (registered trademark) W-2310 manufactured by DIC Corporation) to 100 parts by weight of a soft vinyl chloride resin.

As described above, if the outer layer 9 is formed of a soft vinyl chloride resin that does not contain a migratory plasticizer, the outer layer 9 does not contain a plasticizer to be migrated, so that the hose length can be prevented from shrinking.

According to the present invention, the poor adhesion between the polyether-based thermoplastic polyurethane resin and the vinyl chloride resin is solved by interposing a polyester-based thermoplastic polyurethane resin.

The hose 6 is formed by winding a flexible tape made of polyether thermoplastic polyurethane resin extruded from an extruder in a spiral manner and fusing the adjacent side edges together to form an inner layer 7. A soft tape made of polyester-based thermoplastic polyurethane resin extruded from an extruder is spirally wound and its adjacent side edges are fused together to form an adhesive intermediate resin layer 8 and thermally fused to the inner layer 7. In addition, on the outer side, a soft vinyl chloride resin tape extruded from an extruder with a rigid vinyl chloride resin reinforcing body 10 inside is spirally wound to melt the adjacent side edges. It is manufactured by forming the outer layer 9 and thermally fusing it to the adhesive intermediate resin layer 8.

The present invention is not limited to the above-described embodiment, and can be implemented with the following modifications as long as the properties thereof are not greatly changed.
For example, if the entire hose 6 is formed of a transparent resin, the contents circulating inside can be confirmed. Moreover, if the earth wire which consists of a copper wire is coextruded in the resin tape which comprises the outer layer 9, and an earth wire is embed | buried in the outer layer 9, the outstanding antistatic effect by an earth wire can be exhibited.

Moreover, in the said embodiment, although the outer layer 9 shape | molded with the soft vinyl chloride resin demonstrated as an example the form by which the helical reinforcement core 10 made from a hard vinyl chloride was embed | buried, the spiral reinforcement core 10 is made into the outer layer 9. Instead of being embedded, it may be attached to the outer surface of the outer layer 9 so that a part thereof is exposed to the outside.

The synthetic resin flexible tube of the present invention has an inner layer that retains excellent properties unique to a polyether-based thermoplastic polyurethane resin, such as wear resistance, flexibility, and hydrolysis resistance, and a vinyl chloride resin as an outer layer of a hose. The adhesive strength is excellent, and for example, excellent durability can be expected as a flexible hose made of synthetic resin for transporting slaked lime in waste (garbage) incineration facilities.

Partial sectional view showing an example of a synthetic resin flexible tube

Explanation of symbols

6 Synthetic resin flexible tube 7 Inner layer 8 Adhesive intermediate resin layer 9 Outer layer 10 Spiral reinforcing core

Claims (4)

The inner layer is formed of a polyether-based thermoplastic polyurethane resin, and this inner layer is bonded and integrated with an outer layer made of a soft vinyl chloride resin through an adhesive intermediate resin layer made of a polyester-based thermoplastic polyurethane resin. A synthetic resin flexible tube. The synthetic resin flexible tube according to claim 1, wherein a non-migrating plasticizer is added to the outer layer of the soft vinyl chloride resin. The synthetic resin flexible tube according to claim 2, wherein a plasticizer is not added to the inner layer. The synthetic resin flexible tube according to claim 2, wherein a plasticizer is not added to the intermediate layer.

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