Method of forming bonded seams of spunbonded polyolefin fabric and cleanroom garments including such seams

• US 4,938,817 A
• Filed: 12/30/1988
• Issued: 07/03/1990
• Est. Priority Date: 12/30/1988
• Status: Expired due to Fees

• Current Assignee: Kappler Safety Group
• Original Assignee: Kappler Safety Group
• Inventors: Langley, John D.
• Primary Examiner(s): Wityshyn, Michael
• Application Number:
  US07/292,504
• Time in Patent Office: 550 Days
• Field of Search: 156/73.1, 156/73.4, 156/157, 156/290, 156/227, 156/203, 156/217, 156/223, 156/380.1, 156/466, 156/580.2, 428/57, 428/62, 2/275
• US Class Current: 156/73.1
• CPC Class Codes: A41D 13/1236 Patients' garments
• CPC Class Codes: A41D 27/245 made by welding or gluing joining of plastics by welding or gluing B29C65/00; sewing machines for concurrently making thread and welded seams D05B17/00; thermal or chemical fixing of seams and hems D06M
• CPC Class Codes: B29C 53/36 Bending and joining, e.g. for making hollow articles B29C53/56 takes precedence
• CPC Class Codes: B29C 65/08 using ultrasonic vibrations non-plastics element to plastics elements B29C65/645
• CPC Class Codes: B29C 65/083 using a rotary sonotrode or a rotary anvil
• CPC Class Codes: B29C 66/112 Single lapped joints
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/135 Single hemmed joints, i.e. one of the parts to be joined being hemmed in the joint area
• CPC Class Codes: B29C 66/21 said joint lines being formed by a single dot or dash or by several dots or dashes, i.e. spot joining or spot welding
• CPC Class Codes: B29C 66/232 said joint lines being multiple and parallel, i.e. the joint being formed by several parallel joint lines
• CPC Class Codes: B29C 66/3452 Making complete joints by combining partial joints
• CPC Class Codes: B29C 66/43 Joining a relatively small portion of the surface of said articles B29C66/45 takes precedence
• CPC Class Codes: B29C 66/431 Joining the articles to themselves B29C66/4322 and B29C66/4332 take precedence
• CPC Class Codes: B29C 66/4322 by joining a single sheet to itself B29C66/4332 takes precedence
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/7294 Non woven mats, e.g. felt
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/81433 being toothed, i.e. comprising several teeth or pins comprising a single tooth B29C66/81429, or being patterned
• CPC Class Codes: B29C 66/83411 Roller, cylinder or drum types B29C66/83431 takes precedence; rollers, cylinders or drums moving relative to and tangentially to the parts to be joined B29C66/8362
• CPC Class Codes: B29K 2023/00 Use of polyalkenes or derivatives thereof as moulding material
• CPC Class Codes: B29K 2023/06 : PE, i.e. polyethylene
• CPC Class Codes: B29K 2313/00 : Use of textile products or fabrics as reinforcement B29K2105/06 takes precedence
• CPC Class Codes: B29K 2313/02 : coated
• CPC Class Codes: B29L 2031/48 : Wearing apparel
• CPC Class Codes: B29L 2031/768 : Protective equipment B29L2031/4821 takes precedence
• CPC Class Codes: Y10T 156/1046 : Bending of one lamina only
• CPC Class Codes: Y10T 156/1051 : by folding

Abstract

Bonded seams for joining nonwoven, spunbonded polyolefin fabric to itself are prepared by overlapping of edge regions of the fabric with linen sides of the fabric in contact with one another and first applying heat and pressure along a seam line by means of ultrasonic energy and an embossed wheel, giving a lightly bonded strip. The strip is then folded against an adjacent surface, and heat and pressure are applied from the opposite side of the fabric and over the underlying folded-over strip. This procedure in effect merges the bond produced by the second application of heat and pressure with the first bond, giving a strong bond. Cleanroom and protective garments may be fabricated to include such seams, with the side of the seamed fabric that has a remaining cut edge at the seam being disposed on the inside of the garment. Such garments avoid release of microscopic particles such as occurs for stitched seams.

Claims

1. The method of forming a seam joining together a pair of edge regions of a nonwoven, spunbonded polyolefin fabric having a linen side and a rib side which comprises:

placing said edge regions in stacked relation with linen sides of said fabric edge regions in contact with one another along a strip defining a seam line;

applying heat and pressure to the stacked fabric along said strip, the heat being applied continuously and the pressure being applied at spaced-apart intervals, whereby said edge regions are weakly bonded to one another along said strip;

folding said strip flat against an adjacent surface of a said edge region; and

applying heat and pressure to the folded strip and the area of said edge region against which the strip is folded from the linen side of the edge region against which the strip is folded and over and along the length of said strip, the heat being applied continuously and the pressure at spaced-apart intervals, whereby a strongly bonded seam between both layers of the folded strip and the edge region against which the strip is folded is produced.

2. The method as defined in claim 1 wherein the heat applied in each bonding step is in the form of ultrasonic energy.

3. The method as defined in claim 2 wherein the pressure applied in each bonding step is applied by means of an embossed wheel.