Method for preparing plastic lancet

• US 5,456,875 A
• Filed: 06/03/1993
• Issued: 10/10/1995
• Est. Priority Date: 03/19/1990
• Status: Expired due to Term

• Current Assignee: Becton, Dickinson & Co
• Original Assignee: Becton, Dickinson & Co
• Inventors: Lambert, James M.
• Primary Examiner(s): HEITBRINK, JILL LYNNE
• Application Number:
  US08/070,829
• Time in Patent Office: 859 Days
• Field of Search: 264/328.1, 264/328.12, 264/331.21, 425/577
• US Class Current: 264/328.1
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150282 for piercing elements, e.g. blade, lancet, canula, needle
• CPC Class Codes: A61B 5/150404 Specific design of proximal end
• CPC Class Codes: A61B 5/150511 Details of construction of shaft
• CPC Class Codes: A61B 5/15105 Purely manual piercing, i.e. the user pierces the skin without the assistance of any driving means or driving devices
• CPC Class Codes: A61B 5/15142 Devices intended for single use, i.e. disposable
• CPC Class Codes: B29C 2045/0098 shearing of the moulding material, e.g. for obtaining molecular orientation or reducing the viscosity B29C45/0082 takes precedence
• CPC Class Codes: B29C 45/00 Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor injection blow-moulding B29C49/06
• CPC Class Codes: B29C 45/261 having tubular mould cavities

Abstract

A plastic article having a sharp point is made of a polymer of high impact strength and high hardness. The article may be a lancet or a needle for skin puncture, suturing or sewing. A method for preparing the article includes shear thinning a melt of a polymer and introducing the shear thinned melt into a mold which includes a sharp point.

Claims

1. A method for preparing a plastic lancet having a point comprising:

a) heating a thermoplastic polymer selected from the group consisting of a liquid crystalline polymer, impact resistant acrylic, impact resistant polystyrene and polyurethane having a hard segment of about 90% or greater to give a melt;

b) passing said melt through an orifice whereby said melt undergoes shear-thinning, and decreases in viscosity;

c) directing said melt of reduced viscosity into a mold which includes a sharp point whereby said melt completely fills said mold;

d) cooling said melt in said mold whereby said melt solidifies to an article having the shape of said mold including a sharp point; and

e) removing said article from said mold.

2. The method of claim 1 wherein said melt is passed through said orifice under pressure.

3. The method of claim 1 further comprising machining said point to further sharpen said point.

4. The method of claim 1 further comprising thermoforming said point in a heated tipping die to further sharpen said point.

5. A method for preparing a plastic lancet having a point comprising:

a) directing a melt of a shear-thinned thermoplastic polymer having a durometer hardness of at least 70 Shore D and an impact strength of at least 1.0 ft-lbs/in into a mold which includes a point whereby said melt has a viscosity low enough to completely fill said mold;

b) cooling said melt in said mold whereby said melt solidifies to an article having the shape of said mold; and

c) removing said article from said mold.

6. A method for preparing a plastic lancet comprising:

a) heating an impact resistant, thermoplastic acrylic to give a melt;

b) forcing said melt under pressure through an orifice whereby said melt undergoes shear-thinning and decreases in viscosity;

c) directing said melt of reduced viscosity into a mold which includes a point whereby said melt completely fills said mold;

d) cooling said melt in said mold whereby said melt solidifies to a lancet having the shape of said mold; and

e) removing said lancet from said mold.