ADVANCED ADHESIVES Your corrugating adhesives newsletter OCTOBER 1999 REPORT from Harper/Love Adhesives Corporation Understanding wet strength: What are MRA, WRA, and WPA?

Customize your adhesive This level of resin would typical- 2. Water Resistant Adhesive formula to deliver the wet ly be used in a lightweight board (WRA) combination where no exposure strength you need. WRA probably has the widest to increased humidity may occur. range of applications due to the o determine the “wet No TAPPI test method is fact that most corrugated box strength” needs of a recognized to evaluate this level plants only have the ability to Tcorrugated box plant, we of “wet strength.” Generally, a make one type of “wet strength” must first define the level of “wet one-hour soak test using a similar adhesive. Water Resistant strength” needed. Generally, our procedure to TAPPI method T-812 Adhesive will have between 1% industry has accepted three levels will be sufficient. If the board and 1-1/2% resin relative to the of “wet strength” adhesive. does not float apart, the box liquid volume of the batch. This 1. Moisture Resistant (MRA) Ð meets the minimum level of adhesive formula can be used on used for the lightest possible moisture resistance. lightweight boxes using normal or applications. domestic starch settings. When running heavyweight boards, 250- 2. Water Resistant (WRA) Ð pound test and above with greater medium level of performance. ere are sample starch for- end use demand, it is necessary mulae for MRA, WRA, and 3. Waterproof (WPA) Ð highest H to open the glue gap settings, at level of performance. WPA adhesive, assuming a typ- least an additional .004”, ical 650- to 750-gallon batch*. For all practical purposes, we especially at the singlefacer. know of no box plants running all MRA: 4 to 5 gallons of wet Also, a minimum stack cure time three levels of “wet strength” as strength resin. Application is of 4 hours is essential for well as domestic adhesive, but for same as domestic. optimum results. clarification, we will attempt to WRA: 8 to 10 gallons of wet The typical test method for WRA identify the key characteristics of starch is TAPPI T-812, commonly each type of “wet strength” strength resin. Application is called the 24-Hour Soak Test. adhesive and when it would be same as domestic. An additional test which is used. We will also discuss proper WPA: 10 to 15 gallons of wet suitable for heavier test board test methods to determine the strength resin. Application is (over 250-pound C Flute) is the level of water resistance of a par- 50 % more than domestic. wet pin adhesion test. This test ticular box. Loads are stack cured for a procedure is described in TAPPI 1. Moisture Resistant Adhesive minimum of 4 hours. T-821, and a generally accepted (MRA) norm is that the wet pin adhesion *In a typical 300-gallon batch, MRA most closely resembles value should be at least 4 pounds domestic adhesive in formulation all quantities are halved. per 2 lineal feet of glue line. and application. A typical MRA starch will contain approximately (wet strength, continued) .5% to 1% liquid resin relative to the liquid volume of the batch. (next page, please) 3. Waterproof Adhesive (WPA) adhesive values will be 8 to 12 Guidelines WPA is the highest level of “wet wet pins per 2 lineal feet. 1. Use fresh starch with at strength.” This in itself is a mis- References nomer in that all starch is water least a 25% batch solids for soluble. This type of adhesive TAPPI Technical Information MRA and 28% solids for WRA would typically be used in the Sheets: and WPA. most demanding applications. In ¥ T-812 Ply Separation of Solid 2. Use freshly resinated addition to using 1.5% to 2% “wet and Corrugated Fiberboard adhesive, not more than 6 strength” resin in relation to the (wet) hours old. liquid volume of the batch, it is ¥ T-821 Pin Adhesion of 3. Apply the same glue line in essential that additional starch be Corrugated Board by light applications and approxi- applied to the board. It must be Selective Separation mately 50% more for 250 - allowed to cure in its original pound test and above. stack for a minimum of 4 hours before processing. 4. Allow the board to cure in its original stack for a minimum The TAPPI test method is the of 4 hours. Twenty-four hours same as moisture resistant cure time is recommended for starch, but typically, the wet-pin wax impregnated board.

Anthony Coleman and Craig and supervisor, and has been George join our technical staff deeply involved in process New faces on the with more than 40 years of improvement. Craig will be based combined corrugating experience. in the Orlando area to support a Harper/Love team Each has worked as an operator growing customer base in the southeast. Anthony will work out of Charlotte. Harold L. Fortney will work exclusively with Harper/Love as a consultant. He specializes in areas such as project planning and management, waste management systems, labor standards development, and more. During his 45-year career, Mr. Fortney has worked as senior industrial engineer, general manager, director of corporate services, vice president/chief operating officer, and plant manager. He has been an active leader in many trade associations, including TAPPI, which he joined in 1970. Mr. Fortney lives in Belle Plaine, Kansas. FROM LEFT: Anthony Coleman, Craig George, Harold Fortney. See us at TAPPI Stein-Hall vs. Love cup conversion. he measurement of viscosity is a We’ll be in Booth 235 at Tcritical quality-control check. Most people use a Love cup or a the Hyatt Regency in Stein-Hall cup, measuring the flow Chicago to meet, greet, in seconds. The Love cup flows faster, because it has a larger and mingle. Please drop aperture. by to say hello. Assuming a constant tempera- ture, how much faster the Love cup Also, Pete Snyder will offer a flows depends on viscosity. For great training opportunity in a example, at 100o F, 7 seconds workshop presentation entitled Love = about 15 seconds S.H. but Starch Adhesive Management. 80 seconds Love = about 117 The program, which focuses on the seconds S.H. It is not a straight- line curve. bonding process on the corrugator, will be the central theme of the We’ve developed a chart that compares Love cup times to S.H. Production Committee Workshop. cup times across a wide range of The material has been presented viscosity. to numerous industry groups since For a copy of the chart, and more 1990 and has been updated information about measuring recently with computer-generated Pete Snyder’s 2-hour starch manage- viscosity, contact your Harper/Love representative. slides and a new video production ment program is scheduled for 9:30 a.m. entitled,The Secret Life of Starch. on Wednesday, November 3.

New representative Don’t throw away that preprint! in Mexico What do you do with leftover The economical solution is to Harper/Love welcomes ALHU preprint? If you’re throwing it run it print-side in on the double International, Inc., of El Paso, away or recycling it, you may be backer. Until now, that has been Texas, to its growing list of missing an opportunity to save tough because the inks and international representatives. some money. varnishes inhibited penetration The 18-year-old firm has making a good bond difficult to achieve. established contacts with 95% of all corrugating plants in That’s no longer a problem. An Mexico, providing auditing, adhesive formula that uses a consulting, installation and high-solids carrier, plus distribution of corrugating LiquiBondª and our XM-5 penetrant now makes it possible equipment, spare parts, to get a good, fast, penetrating consumables, prime materials, bond on printed and varnished and related services. surfaces. XM-5 penetrant ALHU has field offices in reduces surface tension and Tizayuca, Hidalgo, Mexico. enhances starch adhesive penetration. Its use promotes consistent performance and Fiber tearout on test sample (left) precise quality control. It is an demonstrates strong adhesive penetra- easy-to-use liquid, available in tion in spite of heavy ink coverage. drums and buckets.

Better bond quality bond Better ¥

soak test soak 800-438-3066. at

Exceeds TAPPI 24-hour 24-hour TAPPI Exceeds ¥ representative or call us toll free toll us call or representative

plant, contact your Harper/Love your contact plant,

Little effect on gel temperature gel on effect Little ¥

tion or a demonstration in your in demonstration a or tion

Stable viscosity Stable ¥

For detailed technical informa- technical detailed For

for wet strength wet for

aet s. D approved. FDA use. to Safe ¥

performance, plus resin resin plus performance,

system

using carrier-starch for for carrier-starch using

manual or automatic mixing mixing automatic or manual

Reduces cost compared to to compared cost Reduces ¥

Easy-to-use liquid for any any for liquid Easy-to-use ¥

liquid product. liquid

Single, simple application simple Single, ¥ performance in one easy-to-use one in performance

T

water resistance and high high and resistance water on heavyweight grades heavyweight on

his unique product combines product unique his Increased corrugator speeds corrugator Increased ¥

Outstanding performance. Superior wet strength. wet Superior performance. Outstanding Aquaseal Plus™ Aquaseal

ADVANCED ADHESIVES Your corrugating adhesives newsletter REPORT from Harper/Love Adhesives Corporation Harper/Love Adhesives Corporation 11101 Westlake Drive P.O. Box 410408 Charlotte, North Carolina 28241-0408 800 438-3066 Leaders in the science of making good adhesives betterª www.harperlove.com e-mail: [email protected]

IN THIS ISSUE • Understanding wet strength • Use that leftover preprint • Starch management training • New faces on the HLA team •New agent in Mexico • And more