Bag adhesive

ANTTBIOTTCS - BETA-LACTAMS - BETA-LACTAMTASE INHIBITORS] (Vol 3) -paper bag adhesive [PACKAGING - CONVERTING] (Vol 17)... 

Dextrins have many applications, with adhesives being their primary market (11,96). Dextrins are used as adhesives for case and carton sealing. For this application, borax is often added to the dextrin to add stability and increase viscosity. Dextrins are added to adhesives used in the laminating of products such as paperboard and shipping containers. The paper industry adds dextrins in adhesives for tube winding and bag adhesives. Library pastes, bottle label adhesives, envelop adhesives, gummed tape, and wall covering adhesives all benefit fiom dextrin addition. 

Bag Adhesives Cross pasting Tacky and quick setting Starch-dextrin-mineral filler 25-30 ... 

Some flexible packaging is fabricated by converters into bags and pouches. Bag material is either small monolayer or large multiwall with paper as a principal substrate. Pouches are small and made from laminations. Bags usually contain a heat-sealed or adhesive-bonded seam mnning the length of the unit and a cross-seam bonded in the same fashion. 

Applications. Preformed bags are opened by the packager, filled with food product, and closed by adhesive, heat-sealing, clipping, stitching,... 

The majority of the imported gum karaya is used by the pharmaceutical industry as a bulk laxative, in dental adhesives, and in sealing gaskets for colostomy bags. 

The adhesives (qv) used to form tube seams and bag bottoms include unborated dextrin, borated dextrin, casein, latex—casein, latex, poly(vinyl acetate), vinyl acetate copolymers, and hot-melt materials (10,27). Dextrin and casein adhesives are more commonly used in the production of grocery sacks vinyl acetate-type adhesives are commonly used in ah paper multiwah bags. The hot-melt adhesives are typicahy used to tack the phes of the multiwah bag together and to form the seam and bottom joints when polymer film phes or coated paper phes are used in bag constmction. 

Poly(vinyl acetate) emulsions are excellent bases for water-resistant paper adhesives destined for use in manufacturing bags, tubes, and cartons. Glue-lap adhesives, which require moderate-to-high resistance to water, exemplify this type. When routine water resistance is required, a homopolymer vinyl acetate emulsion containing a ceUulosic protective coUoid is effective for most purposes. Next effective are emulsions containing fuUy hydrolyzed poly(vinyl alcohol) as a protective coUoid, foUowed by those containing partiaUy hydrolyzed poly(vinyl acetate). 

Most open-mouth bags are closed by sewing, whereas adhesive is used for the pinch type. The pinch bag has been the subject of inten-... 

Complete siftproofness can be had by the tape-over-sewn procedure, whereby the tape is glued onto the finished sewn closure by a device downstream from the sewing head. For siftproofness at high production rates, the pinch-style glued closure is used. The pinch-bag closure has the adhesive preapphed to the open end by the Bagmaker. After the bag has been filled, the closing machine reactivates the adhesive by heat prior to sealing. 

The primary non-woven applications for hot melts are in disposable articles such as diapers and sanitary napkins (see Fig. 22). These articles are made by high speed processes and are immediately packaged in sealed plastic bags, thus they are prime candidates for hot melt use. The applications are broken down into three categories, requiring three different types of adhesives construction, elastic attachment, and garment attachment. 

Both EVA and PE-based adhesives are commonly used for bags. EVA-based formulas typically use lower levels of VA ( 18%) compared to case and carton adhesives to improve heat and blocking resistance. For both EVA and PE adhesives high levels of polymer (45-75%) are used for maximum strength. Adhesion is generally better and blocking slightly worse for EVA vs. PE. 

For very difficult to adhere bag substrates, such as poly-coated bags, or where extreme chemical resistance is needed, polyamide hot melts are used. These adhesives are very lightly formulated if at all. They provide soft adhesives with outstanding heat and chemical resistance, but at roughly double the price. 

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