Adhesives for Corrugating Industry
Types of Packaging - Rigid Boxes ( Set up Boxes)
are very common type of packing , mainly associated with Luxury Products.
Generally they are 4 times thicker than average Folding Carton.
How Rigid Boxes are Made
from sheets called as chipboard ( grey board / plain board/colored )
Cutting and scoring dies are used to cut the board
the sides are scored ( not cut all the way through to facilitate
folding )
Wrap is glued to the outside of
the Rigid Box
Rigid Box Styles “ Telescope
Lids ” have a lid that covers ,
entire base ( Full Telescope)
on chocolate or candy lids
covers entire box has "thumb
cuts" , for ease of opening
“
Telescope Lids ” just a part of
base ( Partial Telescope)
the
fully telescopic style Tray with sleeve or slipcase , or shell &slide
Neck Box or Shoulder Box
a trey is glued inside the base and extended up past the top of the
box. The extension creates a neck and the top edge of the extension
becomes the shoulder
sometimes the neck is made extralong and it extends past the base so that a gap is created between the lid & base . Generally this
is done for esthetic look
Other varieties
Hinged Lids
Flip Top or Cigar Box
Book Style
Clamshell Style
Types of Adhesive Used in Corrugation Carton Manufacturing
Adhesive used can be classified based on the raw material used for its manufacturing. Adhesives
can be broadly classified into three categories.
 Sodium Silicate
 Synthetic Adhesive
 Starch Based Adhesive
Sodium Silicate:
Sodium silicate, as an adhesive, is past. It was used decades back to adhere the top paper to the 2
ply liner. Also referred to as liquid glass or water glass, this adhesive is highly alkaline in nature.
The high alkalinity of this adhesive reduces the longevity of the board produced.
The paper of the produced board deteriorates completely over a period of time. The printing begins
to fade away and vanishes eventually.
The use of Sodium Silicate as an
adhesive for corrugated cartons has
been banned in many countries,
including
India,
for
use
in
pharmaceutical and food industry.
Synthetic Adhesive:
Synthetic adhesive refers to the adhesive that is derived from resin-based emulsions such as a
suspension of polyvinyl acetate in water. Synthetic adhesive constitutes a meagre share in the
market for manufacturing of Corrugated Cartons. Fevicol is an example of synthetic adhesive used
in the manufacturing process.
The use of this adhesive is not very popular because it is very costly and dramatically increases
the cost of production. This adhesive is nearly double the cost of starch based adhesive.
Starch Based Adhesives :
Starch based adhesive refers to the adhesive derived from starch obtained from sources like maize
and tapioca. It has gained a lot of popularity due to the economical cost and the strength that it
offers. Presently, it is the widely used adhesive in the Corrugated Carton Manufacturing Industry.
Problems related to machine damage, paper
deterioration and printing faced with use of
Sodium silicate adhesive are eliminated with
the use of starch based adhesive.
The use of this adhesive penetrates into the
paper fiber adding more strength to the board.
How starch based adhesives differ from
synthetic adhesive and what impact each of
these adhesives have on the quality of output
will be discussed
Starch Adhesive for Corrugated Box Manufacture
Adhesives Formulation
Applicable Type
Waterborne Adhesives, Naturalbased Adhesives
Applicable Base Polymer
Starches
Applicable Industrial Sectors
Papers & Packaging’s
Applicable Base Polymer Properties
Starch adhesives are readily available, low in cost, and easy to apply from water dispersion. They
are considered to be the least expensive class of paper packaging adhesive. Formulated starch
adhesives can be applied hot or cold, but generally are used hot. Starch adhesives cure by the loss
of moisture. These adhesives cure to a thermosetting structure, they have excellent heat resistance.
Disadvantages include poor moisture resistance and mold growth.
Amylose ?
Amylose is a polysaccharide made of α -D-glucose units, bonded to each other through α (1→ 4)
glyosidic bonds.
It is one of the two components of starch, making up approximately 20-30%. Amylose is more
soluble in water than the other component amylopectin.
the long linear chains of amylose more readily crystallize than amylopectin
Amylose is also an important thickener, water binder, emulsion stabilizer, and gelling agent
When amylose concentration is increased, gel stickiness decreases but gel firmness increase
The Stein-Hall Process
The first major commercial process for
producing starch adhesives was the
Stein-Hall
Process.
This
was
introduced in the 1930s for the purpose
of producing an adhesive for
corrugated boxes.
The Stein-Hall system combines the
properties of an 8-9% cooked starch
paste and a 25% starch slurry in a twocomponent, two-container process, as
indicated in Table 2.
Sodium hydroxide is used to lower the
gelation temperature and borax is used
to increase the tack. Crosslinkers and
special starches may be used to impart
water resistance.
The Stein-Hall Process
When the adhesive is applied and heated
to above its gelatinization temperature,
the granules gelatinize, and a very viscous and tacky paste is produced.
In corrugated box manufacturing, the suspended starch should gelatinize immediately on contact
with the heated fluting rolls and develop instant tack at 60-70°C. Starch solids may range from 2030%.
Gradually empty content of upper tank into the lower tank with efficient mixing and agitate until
viscosity is consistent. Finally add preservative and other additives as required.
The high viscosity cooked starch paste serves as a carrier to prevent the starch granules in the
slurry portion from settling out.
When the adhesive is applied and heated to above its gelatinization temperature, the granules
gelatinize, and a very viscous and tacky paste is produced.
In corrugated box manufacture, the suspended starch should gelatinize immediately on contact
with the heated fluting rolls and develop instant tack at 60 - 70°C.
Starch solids may range from 20-30%.
Manufacture of Starch Adhesive
Heating in water is the simplest method of breaking up starch granules.
On heating in water, starch granules first swell and then burst open with a resulting thickening of
the suspension.
The temperature at which this thickening of the suspension occurs is called the gelation
temperature.
For most starches in pure water, gelation occurs between 57 and 72°C (see Table 1). In this form,
the starch is not a true solution but a colloidal suspension.
The heating process can take one of two forms.
Manufacture of Starch Adhesive
In the first, salts (usually the chlorides of metals such as calcium, magnesium and zinc) are added
to a suspension of the starch in water,
and the adhesive is produced by controlling temperature and the time of stirring.
In the second and primary method, caustic soda is added to the starch suspension; the product is
neutralized with acids later in the process.
The starch paste now has a high viscosity and acts as an adhesive.
If the concentration of the starch is above 7%, then the cooked paste is very viscous and difficult
to pump.
Above 15% starch solids content, the cooked paste forms an immobile rubbery mass on cooling.
Suspensions with a higher amylose/amylopectin ratio will have a higher viscosity.
Manufacture of Starch Adhesive
Pregelation starch is produced by physical modification of the starch to impart the ability to form
a paste easily in cold water.
The process consists of heating the starch slurry to a temperature above the gelation temperature
and then quickly drying the starch before retardation can occur.
The main process equipment used is a heated-drum drier or hot roll.
Unmodified starches, such as those produced by the steps outlined previously, come in powder
form (pregelation) or as high-viscosity, low-solids content pastes that do not show a stable
viscosity with time.
Therefore, several treatments have been developed to provide liquid adhesives that are not subject
to retrogradation and have a viscosity and rheology more suitable for many applications.
Manufacture of Starch Adhesive
These treatment methods include alkali treatment, acid treatment and oxidation.
The gelation temperature can be lowered by the addition of an alkali, such as sodium hydroxide,
to the starch suspension.
If sufficient alkali is added, the starch can be induced to gel at room temperature.
Acid modification of starch is achieved by heating the starch at 49-54°C with small amounts of
aqueous mineral acid, followed by neutralization with a base.
This tends to make for a much thinner solution at the same solids content when compared to
unmodified starch.
Manufacture of Starch Adhesive
Starches prepared in this manner are often known as thin-boiling or high-fluidity starches.
Acid modification is often used when applications require higher solids content but a controlled,
lower viscosity.
Oxidization of starch is usually obtained by treatment with aqueous alkaline hypochlorite.
A starch suspension at pH 8-10 is treated with hypochlorite (5-10% Cl based on starch) for a long
enough time to produce the desired viscosity.
Acid is liberated during the reaction, so base must be added to maintain the pH for optimum
reactivity.
Manufacture of Starch Adhesive
Dried oxidized starch is generally whiter than unmodified starch. Because of the low color, these
starches are often used for the sizing and coating of printing papers.
These oxidized or chlorinated starches behave similarly to acid-modified starches.
However, the oxidized starch has greater tack and adhesive character and, thus, is often used in
adhesive applications.
Resulting Properties
The first major commercial process for producing starch adhesives was the Stein-Hall Process.
This was introduced in the 1930s for the purpose of producing an adhesive for corrugated boxes.
The Stein-Hall system combines the properties of an 8-9% cooked starch paste and a 25% starch
slurry in a two-component, two-container process as indicated in the above table. Sodium
hydroxide is used to lower the gelation temperature and borax to increase the tack.
Tips and Tricks
Native starches are capable of yielding high degrees of water resistance, which may be necessary
for labeling, bill posting, and other applications. Improved cold water resistance can be obtained
with polyvinyl alcohol or polyvinyl acetate blends. These adhesives will also dissolve in hot water,
which is often a benefit. Optimal moisture resistance is obtained through the addition of
thermosetting resins, such as urea formaldehyde or resorcinol formaldehyde.
Manufacture of Dextrin Adhesives
Dextrin adhesives are manufactured by dry-roasting starch in the presence of an acid catalyst.
Through treatments with heat and acid, the starch molecules are hydrolyzed into small fragments,
and then repolymerized into highly branched, readily soluble polymer molecules of moderate size.
Cornstarch is commonly used because of its low cost and ready availability, although other
starches are also used.
Unlike starch, dextrin's are soluble in water.
The severity of the heat and acid treatment determines the degree of solubility, which is the basis
for classifying dextrin’s.
Manufacture of Dextrin Adhesives
Finished dextrin's take a very fine powder form, varying in color from pure white to brown.
There are three main types of dextrin adhesives:
 white dextrin's,
 canary (or yellow) dextrin's
 and British gums.
The differences are determined by the roasting time
and
the
temperature and amount of catalyst used. Table 3
describes the properties of these dextrin adhesives.
Manufacture of Dextrin Adhesives
British gums are dextrin's with the highest molecular weight, and though they are the strongest
adhesives among the dextrin's, their maximum usable-solids content is only approximately 25%.
Yellow dextrin's are the lowest in molecular weight. Materials of this type are available with a
viscosity of only 1700 cps at 60% concentration.
White dextrin's have the lowest color of the
three, and their molecular weight is intermediate
between those of the other two.
The range of solubilities of dextrin adhesives are
advantageous in that they may be used to
formulate a variety of solutions of very different
viscosities, creating a variety of gel strengths.
Manufacture of Dextrin Adhesives
These formulations can then be further modified as described in the next section. The same
additives and processes used for starch adhesives are generally used to formulate dextrin
adhesives.
Dextrin's are often preferable to starch, as they need less or no cooking and much less water to
form the paste.
This means that drying time is reduced and there is little likelihood of mold infection in warmer
climates.
Manufacture of Dextrin Adhesives
As adhesives, dextrin's are used in many of the same applications as starch adhesives. Dextrin's
are also used as a core binding material in the manufacture of foundry cores.
Here, the main function is to provide good green strength and to prevent deformation of the core
before being fired in the oven.
Applications for Dextrin Adhesive
Corrugation Glue
what you should know ?
1. Starch Adhesive Components
2. Adhesive Characteristics
3. Adhesive Process Control ( QC )
4. Iodine Staining
5. Issues that can be diagnosed with the Iodine staining method
Starch Adhesive Components
1. Water
2. Secondary Starch
3.
4.
5.
a)
b)
Caustic Soda
Borax or Boric Acid
Other
Preservatives
WRA
c) Bond Enhancer
d) Defoamer
Water :
1. Necessary Component in gelatinizing starch
a) cooking raw starch
b) swelling starch granules
2. Reduce carrier temperature
3. Dilutes to permit pearl starch addition
4. Controls viscosity
5. Inexpensive
Vehicle for Adhesive Penetration
Native Starch
• Has natural adhesion properties
• Can be dissolved in water using heat or chemical energy
• Once dissolved in water and then dehydrated, it “Set Back” to
form a sticky paste and eventually a rigid film of adhesion
• Possesses a significant Affinity for paper
• Gelatinizes to form the bond between the two sheets of
paper i.e. “Green Bond” Formation
Caustic
• Controls the gel temperature
• Provides the chemical energy to dissolve the primary starch [Helps to cook the Starch]
• Provides some “bite” into the paper
• Imparts a stringy, sticky texture to adhesive
• Due to its high alkalinity, it also provides waterproofing by promoting the cross linking between
the keto-aldehyde WRA and starch.
• Available as flakes, coarse or fine pearls and liquid (40 – 50%)
Very Corrosive
Borax Or Boric Acid
• Comes in two forms ( 5 or 10 moles ). Both are the same but
contain a different amount of water.
• Acts as HUMECTANT (good water holding capability)
• Provides tack to adhesive
• Affects gel point
• Imparts viscosity
Improve flow properties
Other Components
• Preservatives (Biocides)
• Penetrating agents [Tee-pol]
• De–foamer’s
• WRA - common ones are: Corwet K6, BL10, BL5, BL1, Aqua mat
B, CP88 and WP 795.
Additives OR Performance enhancers e.g. CAS 901, Starch Booster
Additives and Modifiers
Properties of starch and dextrin adhesives that can be modified
through formulation variables include:
 viscosity
 solids content
 stability
 tack
 slip
 substrate penetration
 drying rate
 flexibility
 water and fungus resistance
and
cost
These formulations generally depend on the type of starch and modification as indicated above,
as well as the additives used.
Frequently, dextrin adhesives-and sometimes starch-based adhesives-are formulated with borax
(sodium tetraborate) to obtain high tack at moderate concentrations and viscosities with good aging
characteristics.
They also have good adhesion and machining properties.
The borax is generally added in amounts of up to 10% based on dry starch.
Sodium hydroxide is also added to convert the borax to the more active sodium metaborate.
Applications include case sealing, carton sealing, bag seams, tube winding and laminating.
Plasticizers are widely used to control brittleness of the glue line and to regulate the speed of
drying.
Common plasticizers include glycerin, glycols, sorbitol, glucose and sugar.
These types of plasticizers act as a hygroscopic agent to decrease the drying rate of the film.
Plasticizers based on saps, poly glycols and sulfonated oil derivates lubricate the layers within
the dried adhesive and, thus, impart flexibility.
Urea, sodium nitrate, salicylic acid and
formaldehyde plasticize by forming a solid
solution with the dried adhesive.
Chemicals such as calcium chloride, urea,
sodium nitrate, thiourea and guanidine salts are
used as liquefiers to reduce viscosity.
They are also used as humectants to control
open time and speed of drying. They are usually
added at about 5-20% based on dry starch.
Colloid stabilizers, such as soaps and sodium
chloride, are sometimes used to retard the tendency to retrogradation.
Native starches are capable of yielding high degrees of water resistance, which may be necessary
for labeling, bill posting and other applications.
Improved cold-water resistance can be obtained with polyvinyl alcohol or polyvinyl acetate blends.
These adhesives will also dissolve in hot water, which is often a benefit. Optimal moisture
resistance is obtained through the addition of thermosetting resins, such as urea formaldehyde or
resorcinol formaldehyde.
Mineral fillers, such as kaolin clay, calcium carbonate and titanium dioxide, are often used in
starch and dextrin adhesives to reduce cost and control penetration into porous substrates.
They are usually used at concentrations of 5-50%. Thixotropic agents like bentonite are also often
used in certain applications to control viscosity.
Other additives that are found in starch- and dextrin-based adhesives include preservatives,
bleaches, and defoamers.
Preservatives that are commonly used to prevent microbial activity include formaldehyde (35%
solids) at 0.2-1.0%, copper sulfate at about 0.2%, zinc sulfate, benzoates, fluorides and phenols.
Possible toxic effects must be carefully considered before choosing a preservative.
Common bleaching agents include sodium bisulfite, hydrogen and sodium peroxide, and sodium
perborate. Organic solvents are sometimes added to improve adhesion to waxed surfaces.
Adhesive Characteristics
Four principal characteristics governing the bonding process:
• Solids
• Viscosity
• Gel Temperature
• Adhesive Temperature
Solids
Study showed that high solids formulations i.e.
24% and above have some advantages:
• Better viscosity stability
• Provides better bonding
• Less water, therefore better control of warp and less
washboard
• High machine speeds
• Accurate glue gap settings will results in reduced starch
consumption.
Viscosity
NB: Viscosity measurement must ALWAYS be recorded together
with the temperature of the Glue.
Factors contributing to viscosity loss are:
• Shear i.e. pumps, agitators, t-piece, etc.
• Microbiological degradation
• Temperature
• Primary starch
• Long storage time
• Too much water in the recipe
Coatings can create a problem
Like jelly formation
In single or double roller coating units
Gel Point
• The gel point is the temperature at which the
first signs of adhesive thickening occurs
• At the gelatinization temperature, the viscosity
of the adhesive changes rapidly and influences
the penetration into
the board and hence the bonding.
Adhesive Temperature
• The temperature of the adhesive is often
neglected.
• Since it has a major effect on the viscosity it is
of Critical
Importance
• A more consistent quality of bonding can be achieved if the
temperature and the viscosity are constantly monitored
together and kept under control
Adhesive Process Control
(Quality Control)
There 4 tests which can be done in the plant to ensure the
uniformity of the adhesive from batch to batch over
• Viscosity
• Temperature
• Gel Temperature
• % Solids
prolonged periods of usage.
Starch Adhesive Parameters
What and When to Measure !!
• Viscosity
- In the storage tanks at least every 4 hours
• Adhesive Temperature
- Every time the viscosity is measured
• Gel Point
- At least every 8 hours
• % Solids
- Accurate calculation from formulation
- Laboratory analysis when available.
In Process Testing
What and How Often ???
Machine Crew:
• Viscosity / Temperature
- Twice per 8 hour shift
• Iodine Staining of Glue lines
- Twice per 8 hour shift. However, there is an added
advantage for testing every job
• Paper temperatures
Four times per 8 hour shift
Maintenance Personnel
• Misalignment
• Machine settings
Iodine staining
• It is a useful diagnostic tool at the disposal of the corrugator
crew
• It is easy to do, does not require a lot of training to interpret
the results.
• Can help to pinpoint many common machine or operational
problems quickly.
• The quality of the glue line reflects the quality of the bond.
• Helps to keep track on adhesive application
Examining the liner
• Glue lines are examined for acceptable quality
• Should have consistent width all the way across the web
• NB: It is useful to mark the direction the board ran on the
machine.
Some issues that can be diagnosed with this method
• Application Rate
• Glue roll speed
• Glue rolls out of parallel
• Worn or dirty glue rolls
• Hold – down pressure
• Slinging or Dribbling.
Starch based Adhesive
from sources like maize and tapioca
v/s Synthetic Adhesive
resin-based emulsions such as a suspension of polyvinyl acetate in water
in Corrugated Carton
Manufacturing
impact each one on two major parameters
QUALITY and COST.
Impact On Quality
So let’s first understand the adhesive’s Impact On Quality.
Impact on Bursting Strength
Starch based Adhesive penetrate into the fibers of the paper.
This penetration , creates a strong green bond, & strengthens
the fibers of the paper. Result the Bursting Strength is
positively impacted.
(Kindly note,
highly alkaline adhesive , attracts high levels of atmospheric
and Bursting Strength is negatively impacted.
It is advisable to use low alkali or no alkali / pH neutral
adhesive)
Synthetic adhesive , creates a soft film between two layers of
papers holding them together.
Hence this adhesive does not significant impact on the Bursting Strength of the Corrugated
Carton.
Impact on Stiffness and Compression Strength
The penetration of starch based adhesive in the paper fiber adds to the stiffness of paper.
This improves the Compression Strength and overall stiffness of the Corrugated Carton.
(Kindly note,
highly alkaline adhesive have adverse impact on the Compression Strength, stiffness , &
caliper of the Corrugated Cartons.)
Synthetic adhesive creates a soft bonding film which has no impact on the Compression
Strength and stiffness of the Corrugated Carton.
Impact on Bonding Strength
Starch based adhesive have higher solid content as against the synthetic adhesive .
Solid Content is, proportion of non-volatile material in the adhesive solution. The ideal
percentage of solid content should be approx. 25% for excellent bonding.
Synthetic adhesive with higher solid content are available for wood articles. They are too
expensive.
On the other hand starch based adhesive have 25% solid contents to avoid any delamination issue.
starch based adhesive with 25% solid contents is lot more cheaper.
Impact On Costing
Cost of Adhesive
The synthetic adhesive is more than double the cost of starch based adhesive. This affects the
profitability.
Starch based adhesive are available in powder form.
It is mixed with water, which is available free of cost
or at minimal cost, in the factory by its users. Hence
you pay only for the solid content.
In case of synthetic adhesive, the adhesive is
delivered in liquid form. You have to pay for both,
the solid and liquid content.
Cost of Transportation
The freight paid is also relatively higher, because no freight is paid for water (liquid content) in
case of starch based adhesive.
Other Differences Between Starch Based Adhesive And Synthetic Adhesive
Starch based adhesive has little or no odor. While synthetic adhesive has a strong odor.
Starch based adhesive is made from food items and hence is also bio-degradable in nature. While
synthetic adhesive is not bio-degradable.
Starch based adhesive has gained a lot of popularity due to the economic cost and the strength
that it offers. Presently, it is the widely used adhesive in the Corrugated Carton Manufacturing
Industry. While Synthetic adhesive constitutes a meagre share in the Industry.
Other Differences Between Starch Based Adhesive And Synthetic Adhesive
Starch based adhesive has little or no odor. While synthetic adhesive has a strong odor.
Starch based adhesive is made from food items and hence is also bio-degradable in nature. While
synthetic adhesive is not bio-degradable.
Starch based adhesive has gained a lot of popularity due to the economic cost and the strength
that it offers. Presently, it is the widely used adhesive in the Corrugated Carton Manufacturing
Industry. While Synthetic adhesive constitutes a meagre share in the Industry.
Types of Starch Based Adhesive used in Corrugation Industry
Starch based Adhesive are generally classified based on the process for which it is used as
Corrugation Adhesive
Pasting / Laminating Adhesive
Corrugation Adhesive
Corrugation Adhesive refers to the adhesive used on Single Facer/ Corrugator /Corrugation
Machine.
For Semi-Automatic Operations:
Corrugation Adhesive is used for preparing 2 ply liners. This adhesive is applied on the flute tips
and it is adhered to the Kraft liner.
For Automatic Operations:
Adhesive is used for preparing the Corrugation
Board in fully automatic Corrugation Machines.
The adhesive is applied on the exposed flute tips at
the single facer and double backer station to form a
board.
Adhesive cannot be applied directly with water. This adhesive needs heating in the presence of
water to gain its bonding or adhesion property. Adhesive is mixed with water (in the ratio provided
by your adhesive supplier) and is poured in the gum tray.
It gains it adhesion property when it is applied , in the
presence of heat on the Corrugation and Pressure Rolls.
Pasting Adhesive
refers to the adhesive used on Laminating or Pasting
Machine.
This adhesive is used to stick the top paper to the flutes
the top paper and liners to form 3/ 5/ or 7 ply boards.
This adhesive is used only in Semi-Automatic / Manual
Operations.
Pasting Adhesive, is mixed with water and is used at
room temperature. This adhesive, unlike corrugation adhesive, does not require heat for gaining
its adhesion property.
It is a gelatinized adhesive used
for adhering the top paper
at room temperature.
What’s new ?
C☆RheM Adhesive Rheology Modifier
Optimize starch consumption with C☆RheM™ adhesive rheology modifier
C☆RheM™ modifier has been designed to help the corrugating industry reduce starch
consumption and drying energy use, while improving corrugated board quality and printability. It
provides adhesive flow and film split characteristics to promote superior machine run ability and
board performance.
Reduce energy and increase efficiency
Modifying adhesive rheology with C☆RheM™ modifier supports adhesive add-on. Therefore the
water add-on during the process of manufacturing corrugated board is reduced. Less adhesive to
dry allows for increases in speed. The board becomes flatter, stronger and corrugator waste is
reduced.
Improve your board quality
C☆RheM™ modifier supports the trend for lighter weight papers and helps deliver:
Improved flatness, no wash-boarding
better printability
increased box compression strength
RHEMCORR™ Flow Enhancer
Bringing efficiency to your adhesive
RHEMCORR™ is a rheology modifier
(flow enhancer)
used to create a new starch-based
corrugating adhesive,
allowing adhesive consumption to be reduced
while maintaining bond quality.
1. Lower energy use
2. Less adhesive slinging reducing clean-up and run ability problems
3. Higher quality board due to less warp and wash boarding
4. Less combined-board waste due to less warp and delamination
5. Increased productivity due to less down time and flatter board
6. RHEMCORR™ modified adhesive promotes superior bonding while at the same time
reducing adhesive application.
7. Due to strong hydrophilic properties imparted by the rheology modifier, the
RHEMCORR™ adhesive more tightly binds water and this enables more of the starch at
the flute tip to gelatinize, thereby maintaining bond strength as adhesive amount is reduced.
8. The RHEMCORR™ rheology modified adhesive maintains its consistency especially in
the dynamic corrugating environment. This consistency results in reduced adhesive
spreading down the flute flank where it does not contribute to bond performance.
9. RHEMCORR™ is available in a convenient liquid form. Just program it in for a fully
automated addition to your starch formulation. You can rely on a stable, consistent
dispersion into your adhesive.
Cross-Linked and Carrier Starches
Cross-linked starches for corrugating
For greater wet-bond strength in corrugating, Cargill has developed a starch designed to reach a
higher peak viscosity at its gelatinization temperature.
As glues made with these cross-linked starches yield higher viscosity increases on heating green
bond condition is attained more quickly.
Adhesives prepared with cross-linked starches have , an improved rheological profile for excellent
application on corrugating rolls, superior wet-bond strength (tack) and minimal glue consumption.
Carrier starches
The use of specialty carrier starch improves glue penetration of the paper surface. This is
particularly important when a closed paper surface is used.
The use of specialty starches produces adhesives with greater viscosity stability and shorter
textures, compared with regular starch. Stronger bonds and improved production speeds is
achieved.
Liquid borax
Cargill’s liquid borax has a clear advantage over solid borax-penta / deca-hydrate in its penetration
behavior, result in lower glue consumption & it is easier and safer to handle.
Two different types of liquid borax have been developed, with & without biocide.
It is recommend using (with biocide), because this provides good viscosity stability over time,
and there is minimal risk of bacterial or fungicidal growth.
Water resistant bonding additives
There are different types of products, all provide water resistance (if applied correctly to the
corrugator).
With environmental issues firmly , these products do not contain "free formaldehyde".
There are two types with a film-forming agent, for machine speed reasons.
There is a one-bag mix, containing a solid water resistant additive supplied separately.
It is known that water resistant products influence the viscosity and gel-point of a corrugating
adhesive.
Adaptations to the carrier starch and the caustic level of the glue are therefore always needed.
Cargill’s newest development in this area is a product that can be dosed at the machine, and has
no influence on viscosity and gel-point.
Besides a significant cost saving, that brings
the added advantage of "fresh" application
of water resistance, as it is known that glue
loses functionality if kept too long.
Corrugated Box Sealing Tapes
Manufacturers and packaging line workers
know that the temperature at which a case
sealing operation occurs
has an impact on the success – or failure –
of a carton seal.
This application temperature – the temperature at which packaging tape is applied – is important
to consider,
as extreme hot and cold temperatures can
negatively affect the integrity of many tapes.
In the food and beverage industries, case sealing is
often done in cold environments due to the need to
keep carton contents refrigerated.
When the application temperature is near or
below freezing,
many packaging tapes fail to properly adhere to
corrugated surfaces.
This occurs because packaging tape requires wipe down force in order for the adhesive to penetrate
into the substrate of the carton, and adhesives that are not formulated to perform in cold
temperatures tend to become brittle and lose their stickiness in low temperatures.
In cases where tape is applied in a comfortable temperature but stored or transported in a much
colder temperature – this is referred to as the service temperature – the tape can flag or become
loose over time, subjecting the contents to pilferage or damage.
This is true with water based Acrylic Adhesive coated Packaging Tape.
The reason is the , glass transition temp ( Tg ) of Acrylic is -20 deg C
In such application
Natural Rubber Latex Based Adhesive coated Pkg Tape performs very well , as the ( Tg ) of
Natural Rubber is , -70 Deg C
While it is not as common of a complaint in packaging operations, extreme heat can cause some
packaging tapes to fail
due to shrinking of the backing and pulling away from the substrate of the carton.
This is especially true when tape is stored in a very hot environment for an extended period of time
before being shipped to its destination.
Many times , case sealing in extreme cold or hot temperatures can’t be avoided,
but choosing a packaging tape that is engineered for reliable performance in those harsh
environments
will reduce the need for reworks caused by tape failure, saving time and money.
Another Latest Development is
Use of Water Repellent coating on the top side of the External and Internal side of the Corrugated
box.
This coating provides additional protection , against exposure to Water or Moisture , resulting into
a stronger Box .
These coatings are Biodegradable in nature , hence don’t interfere in the recycling process later
on.