Method for producing needle-equipped outer tube and needle-equipped outer tube

1. A method of manufacturing a needle-equipped outer tube including a needle, a joint member having a needle insertion hole penetrating the joint member from a distal end to a proximal end so as to allow the needle to be inserted therein and a tapered portion in which an outer diameter decreases from a distal end side toward a proximal end side, and an outer tube member including a distal end connecting section having a tapered hollow portion configured to receive the tapered portion of the joint member, the method comprising:

a preheating step comprising heating the distal end connecting section to a temperature that is at or below a softening point of a material forming the outer tube member and higher than a glass-transition point of the material forming the outer tube member, with the joint member inserted in the tapered hollow portion of the distal end connecting section of the outer tube member, and with the needle being inserted or inserted and fixed in the needle insertion hole, such that a portion of the joint member is disposed between an inner surface of the tapered hollow portion and an outer surface of the needle; and

a joint member welding step, performed after the preheating step, comprising thermally welding said portion of the joint member to the tapered hollow portion of the distal end connecting section of the outer tube member by heating the needle while a distal end portion of the joint member is pressed toward the proximal end of the joint member by a pushing member with a pressing force in a range of 4 N to 30 N.

2. The method according to claim 1 , wherein the heating in the preheating step is performed at a temperature in a range of 110° C. to 150° C.

3. The method according to claim 1 , wherein a material forming the joint member and the material forming the outer tube member are thermoplastic resins having compatibility with each other when melting.

4. The method according to claim 3 , wherein the material forming the joint member and the material forming the outer tube member are a same thermoplastic resin or comprise a same base thermoplastic resin.

5. The method according to claim 4 , wherein the material forming the joint member and the outer tube member is cyclic olefin polymer.

6. A needle-equipped outer tube comprising:

a needle;

a joint member having a needle insertion hole penetrating the joint member from a distal end to a proximal end and a tapered portion in which an outer diameter decreases from a distal end side toward a proximal end side; and

an outer tube member including a distal end connecting section having a tapered hollow portion configured to receive the tapered portion of the joint member,

wherein the needle is located in the needle insertion hole,

wherein the joint member includes a thermally-welded section that is disposed between an inner surface of the tapered hollow portion and an outer surface of the needle at a location separated from a distal end of the distal end connecting section by a predetermined distance toward a proximal end,

wherein the thermally-welded section is thermally welded to both the needle and the tapered hollow portion, and

wherein the distal end connecting section has a contact section, which is a non-thermally-welded section that contacts the joint member but is not thermally welded to the joint member, at a location distal of the thermally-welded section, the contact section including a residual strain but no crack,

wherein the contact section has a phase difference in birefringence measurement due to the residual strain, and an occurrence frequency of a phase difference exceeding 800 nm in birefringence measurement is equal to or smaller than one tenth of an occurrence frequency of a phase difference smaller than 800 nm.

7. The needle-equipped outer tube according to claim 6 , wherein the outer tube is manufactured by the method according to claim 1 .

8. The needle-equipped outer tube according to claim 6 , wherein a phase difference exceeding 900 nm does not occur in birefringence measurement in the contact section.

9. The needle-equipped outer tube according to claim 6 , wherein the contact section has a peak in an occurrence frequency in a range of 100 nm to 500 nm of a phase difference in birefringence measurement.

10. A method of manufacturing a needle-equipped outer tube including a needle, a joint member having a needle insertion hole penetrating the joint member from a distal end to a proximal end so as to allow the needle to be inserted therein and a tapered portion in which an outer diameter decreases from a distal end side toward a proximal end side, and an outer tube member including a distal end connecting section having a tapered hollow configured to receive the tapered portion of the joint member, the method comprising:

a preheating step comprising heating the distal end connecting section to a temperature at or below a softening point of a material forming the outer tube member with the joint member inserted in the distal end connecting section of the outer tube member, and with the needle being inserted or inserted and fixed in the needle insertion hole;

a joint member welding step, performed after the preheating step, comprising thermally welding the joint member to the distal end connecting section of the outer tube member with a distal end portion of the joint member pressed toward the proximal end of the joint member by a pushing member with a pressing force in a range of 4 N to 30 N, and

wherein a material forming the joint member and the material forming the outer tube member are thermoplastic resins having compatibility with each other when melting.

11. The method according to claim 3 , wherein the material forming the joint member and the material forming the outer tube member are a same thermoplastic resin or comprise a same base thermoplastic resin.

12. The method according to claim 4 , wherein the material forming the joint member and the outer tube member is cyclic olefin polymer.