Plunger covers and plungers for use in syringes
A plunger cover for use with a syringe includes a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe. The central portion can, for example, be more rigid than the sealing portion. The sealing portion and the central portion are connected in an overmolding process. The sealing portion can, for example, be formed from a thermoplastic elastomer or a thermoplastic polyurethane. The central portion can, for example, be formed from polypropylene, acrylonitrile butadiene styrene, polycarbonate or copolymers thereof.
1. A plunger cover for use with a syringe, the plunger cover comprising:
a sealing portion adapted to form a seal with the syringe; and
a central portion adapted to contact a fluid within the syringe, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process,
wherein the sealing portion is injection molded first and the central portion is injection overmolded thereon,
wherein the central portion comprises a conical hollow portion,
wherein the sealing portion comprises a conical central section,
wherein the sealing portion and the central portion are overmolded such that the conical central section and the conical hollow portion are coextensively connected to form a multilayer conical portion of the plunger cover, and
wherein the plunger cover contains colorant.
2. The plunger cover of claim 1 , wherein the colorant is contained in the sealing portion, the central portion, or combinations thereof.
3. The plunger cover of claim 1 , wherein the sealing portion is formed from a thermoplastic elastomer or a thermoplastic polyurethane.
4. The plunger cover of claim 1 , wherein the central portion is formed from polypropylene, acrylonitrile butadiene styrene, or polycarbonate.
5. The plunger cover of claim 1 , wherein a material for the sealing portion is a first material and a material for the central portion is a second material, the first material and the second material arc different and are selected so that molecular bonding occurs between the sealing portion and the central portion.
6. The plunger cover of claim 1 , wherein the central portion is positioned forward of at least a portion of the sealing portion.
7. The plunger cover of claim 1 , wherein the sealing portion is shaped to not contact the fluid within the syringe.
8. The plunger cover of claim 1 , wherein the sealing portion comprises an inwardly projecting flange seated in a seating formed in a support ring.
9. A plunger for use with a syringe, the plunger comprising:
a plunger cover comprising a sealing portion adapted to form a seal with the syringe and
a central portion adapted to contact a fluid within the syringe, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process; and
a support ring attached to the plunger cover,
wherein the support ring has a forward surface shaped to contact and mate with a rearward surface of the plunger cover,
wherein the central portion of the plunger cover comprises a conical hollow portion,
wherein the sealing portion of the plunger cover comprises a conical central section,
wherein the sealing portion and the central portion are overmolded such that the conical central section and the conical hollow portion are coextensively connected to form a multilayer conical portion of the plunger cover, and
wherein the plunger contains colorant.
10. The plunger of claim 9 , wherein the colorant is contained in the central portion, the sealing portion, the support ring, or combinations thereof.
11. The plunger of claim 9 , wherein the sealing portion is formed from a thermoplastic elastomer or a thermoplastic polyurethane.
12. The plunger of claim 9 , wherein the central portion is formed from polypropylene, acrylonitrile butadiene styrene or polycarbonate.
13. The plunger of claim 9 , wherein a material for the sealing portion is a first material and a material for the central portion is a second material, the first material and the second material are different and are selected so that molecular bonding occurs between the sealing portion and the central portion.
14. The plunger of claim 9 , wherein the sealing portion includes a radially inward projecting flange that is seated within a seating formed on the support ring to connect the plunger cover to the support ring.
15. The plunger of claim 9 , wherein the forward surface of the support ring abuts the plunger cover to prevent rearward motion of the central portion of the plunger cover relative to the support ring.
16. A syringe comprising:
a syringe body and a plunger slidably positioned within the syringe body, the plunger comprising a plunger cover comprising:
a sealing portion adapted to form a seal with the syringe body;
a central portion adapted to contact a fluid within the syringe, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process; and
a support ring attached to the plunger cover,
wherein the sealing portion is injection molded first and the central portion is injection molded thereon,
wherein the support ring has a forward surface shaped to contact and mate with a rearward surface of the plunger cover,
wherein the central portion comprises a conical hollow portion,
wherein the sealing portion comprises a conical central section,
wherein the sealing portion and the central portion are overmolded such that the conical central section and the conical hollow portion are coextensively connected to form a multilayer conical portion of the plunger cover, and
wherein the plunger cover contains colorant.
17. The syringe of claim 16 , wherein the colorant is contained in the central portion, the sealing portion, the support ring, or combinations thereof.