JPS5928595B2 - Adhesive composition for the production of corrugated bodies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an adhesive for the manufacture of starch-based corrugated bodies.

The invention also relates to a method for joining materials, in particular for joining laminates of fibrous, cellulosic fabrics, and more particularly to the production of paperboard for use in producing corrugated containers. The present invention also relates to structures made by using the novel adhesive composition. One of the customary methods for manufacturing corrugated board is to process a strip of paper into a corrugated shape with a corrugating roller, apply adhesive on one side only to the ridges of the vertical grooves of the corrugated body, and then apply a material called a liner. It consists of gluing another paper strip to the vertical grooves using heat under high pressure.

Single-faced corrugated boards are ready for use.

However, this single-faced board is usually sent to the second stage of the corrugated body manufacturing machine called the double hacker stage to produce double-sided (double-faced) boards called double backboards.
processed into something. The term single facer generally refers to the first stage of the machine. Adhesive is applied to the ridges of the opposite longitudinal groove, and a second paper (liner) is adhered to the opposite side using heat under a relatively small amount of pressure. The fact that using large amounts of pressure for gluing the second longitudinal groove of the paperboard tends to destroy the corrugations makes the gluing problem in the second stage extremely difficult. Starch-based corrugated adhesive compositions are disclosed in U.S. Pat. No. 2,051,025 to J.V. Bauer, granted August 18, 1936; US Patent No. 21
The Stein-Hall technique, as described in US Pat. No. 0,2937, has been widely used since its advent.

Steinhall type adhesives are two-component water-based systems.

One component in this system generally consists of heat-treated or gelatinized starch, which is used as the carrier phase. Other components can form relatively viscous aqueous slurries, such as carboxymethyl cellulose, which has also been used as a carrier phase. The second component or phase consists of non-gelatinized starch material.

This second phase is a latent or latent adhesive phase. That is, the adhesive properties of such compositions are such that the adhesive is applied to the ridges of the longitudinal grooves of the corrugated fabric, the liner is pressed against the adhesive coated grooves, and treated with heat and pressure. Thus, the granular starch material is gelatinized by the heat, and the structure is formed for the first time. Swelling and gelatinization of the potentially adhesive phase occurs as the newly bonded corrugated board passes through a hot plate drying system associated with the corrugation manufacturing machinery.

This system also provides partial drying of the corrugated board and allows the adhesive to harden sufficiently to allow subsequent operations such as trimming, cutting, and sheeting without delamination. The degree of initial stickiness in the corrugated board bond is called the green bond strength.

This property determines the ability of the newly formed corrugated board to resist concurrently acting high shear forces that occur during subsequent processing operations such as trimming, cutting, and sheeting operations. . In this case, it is not necessarily necessary to display the final bond strength. Green bond strength, or simply green strength, is the main critical factor for controlling the operating speed at which corrugated boards are manufactured on the machines used. Experienced machine operators often operate the machine at the highest speed it can operate without sheet delamination during trimming, cutting, and sheeting operations. Since resistance to peeling is a property that is directly based on green strength, the properties of the corrugated adhesive play a direct role in the machine efficiency, which in turn affects the speed of disposal of fixed assets exhibited by the machine. Determine. After the corrugated boards have been trimmed, cut and sheeted, they are stacked and sent to storage where the adhesive is cured to full strength.

After the bond is dry and fully cured, the corrugated plate is peeled from the corrugated sheet by gently but firmly pulling the liner. The major advance in corrugated adhesive technology over the last 30 years has been the work of John Hsu Schiernberger and Raymond Pichi Sitzko in 1966.
U.S. Patent No. 335,530, granted Nov. 28, 2007.
It is described in the specification of No. 7.

This patent describes a single phase corrugated adhesive called carrier-free in which partially swollen starch granules are present as a homogeneous phase suspended in an aqueous alkaline vehicle. Substantial operational economies are gained by not using a carrier. The carrierless corrugated adhesives described and claimed in the Schienberger Schitzko patent are used and cured in a manner similar to Steinhall-type adhesive compositions. Other advances in the field of corrugated body adhesives have primarily concerned moisture-resistant construction, generally through the addition of synthetic resins such as urea formaldehyde, phenol formaldehyde, and resortin formaldehyde.

Bauer's patent describes a significant advance in technology over time.

By using his adhesive, Bauer was able to reduce operating time on corrugated board manufacturing machines by up to 20% compared to using conventional prior art adhesive compositions. I am reporting what I can do. Compositions according to the prior art include compositions based on sodium silicate and adhesive compositions based on the use of gelatinized or modified starches, such as starches. In Steinhall-type systems based on the teachings of Bauer, the time required to form an adhesive bond between the corrugated intermediate liner and the liner or facer sheet is essentially due to the moisture content in the adhesive. It is independent of the rate at which it is expelled by heat or absorbed by paper.

According to Bauer, the time required to form an adhesive bond is primarily based on the time required to gelatinize the granular starch particles suspended in the gelatinized starch carrier phase. As the granular starch gelatinizes, water is taken up and the viscosity of the adhesive increases rapidly, immediately forming a green bond. Bauer then believed that tapioca, rye, and potato starches were inherently superior to corn, wheat, and rice starches for producing the corrugated adhesive of his concept. Bauer describes four important factors that are believed to determine the suitability of starch for use as a latent adhesive component in his conceptual system. These four factors are: (1) the time required for the granular starch to be completely gelatinized by the heat in the inlet of the corrugated body manufacturing machine;

(2) Temperature for gelatinization of starch.

(3) Viscosity obtained after gelatinization.

(4) Degree of stickiness obtained after gelatinization.

However, subsequent developments in the concept taught that green bond strength is primarily due to evaporation of moisture from the side of the binder; Thayer and ThOmas: Analysis of glue in collagen board; TAPPI 22nd Corrugated Container Conference, May 1971.

The inventors have now discovered that selected types of starch materials exhibit excellent properties when used as adhesive components in corrugated body adhesive compositions.

One of these advantages is that conventional Steinhall-type corrugated adhesive compositions or the more recently introduced carrier-free corrugated adhesive compositions can be used at generally the same level of adhesion. Machine operating speeds typically 50 to 100% faster than would otherwise be possible. In other words, the primary active adhesive component in the corrugated body adhesive composition exhibits at least about 30% greater area and instruc- ture in the instruc- ter one hour heating curve when compared to unmodified corn starch under the same test conditions. Excellent results are obtained with saponifiable starch esters that exhibit at least about 30% greater area in the Rocker one hour cooling curve.

Adhesive compositions according to the invention have at least about 0.015
Preference is given to using the main adhesive component as a saponifiable starch ester with a saponifiable degree of substitution (D.S.) of . As used herein, the term "saponifiable degree of substitution" refers to the total degree of substitution of all saponifiable ester groups on a starch molecule. Particularly preferred starch esters are starch acetate, starch succinate and starch acetate succinate. One of these active adhesive ingredients
Advantageously, the use of one or more types in either Steinhall type compositions or carrier-free type compositions is a significant improvement over the prior art. The most preferred adhesive component is starch acetate succinate having a degree of saponifiable substitution within the range of about 0.025 to 0.045.

These substitution degree levels indicate the range that can be applied to acetic acid co-citric acid starch. Other derivatives of interest according to the invention have their own range of degrees of substitution. in general,
If the degree of substitution is too low, the derivative material will not exhibit too much improvement over unmodified cornstarch when used in corrugated adhesive compositions. If the degree of substitution is too high, the gelatinization temperature cannot be used operationally. Particular substances defined for use according to the invention are starch derivatives as defined above. These starch derivatives can be manufactured in situ prior to use, i.e. on a corrugated body manufacturing machine, or they can be manufactured during operation and processed for such purposes according to processes according to the prior art. Other starch materials used in the corrugated adhesive compositions may also be incorporated into the corrugated adhesive composition. It is also possible to use modified starch which can be produced from the above starch esters.

These modified starches are produced by essentially complete saponification of starch esters and removal of the salts formed. The resulting modified starch is then dried. Although this derivative is essentially completely separated from the starch material, this modified starch still retains the advantageous properties of the ester. Although the reason why the substances specified by the present invention are particularly effective when used in corrugated body adhesives has not yet been fully elucidated, these substances have been gelatinized. It can be theorized that not only does this provide an unusually high viscosity during the process, but in addition, a high degree of green strength is obtained without the need for evaporation of the solvent.

Although the final form of the starch material useful in accordance with the present invention has not yet been determined, the ester can be essentially completely dissolved within a short period of time under the circumstances in the mixing equipment of the corrugated body manufacturing machine. It is known to be saponified.

The present invention will be further elucidated by a more detailed description of several specific embodiments thereof.

Parts and percentages listed are by weight on a commercial basis unless otherwise specified. The commercial basis for starch materials contains about 12% moisture. Proper selection of the primary active adhesive component is of critical importance in the proper practice of this invention.

For the production of saponifiable starch esters for use as the main active adhesive component, the starting starch can be obtained from any crop. For example, corn, wheat,
Those obtained from non-waxy monograin sources such as rice and grain sorghum are preferred. The term starch as used herein has a broad meaning and includes powders, unmodified starches and crumbs. Cornstarch is preferred as the starting starch. The raw starch is esterified to produce the primary active adhesive component having the desired properties in the present invention as described herein.

In typical corrugated body adhesive compositions, borax and caustic are commonly added to enhance adhesion and tack and to adjust the gelatinization temperature.

When using a carrier-type or carrier-free adhesive composition,
In all cases, the Steinhall viscosity of the composition must be within the conventional range to allow adequate amounts of adhesive to be applied to the flutes over the entire speed range of the machine.
Generally, to facilitate operation of corrugated body manufacturing machinery, the adhesive composition should have a Steinhall viscosity in the range of about 20 seconds to about 100 seconds. The optimum Steinhall viscosity of the composition is determined by the particular corrugated body manufacturing equipment. Unless specifically limited, the materials described herein and identified in the claims are those that are added to form the adhesive composition.

Under certain conditions of the adhesive composition, the morphology of certain materials can be modified. For example, starch esters are saponified in typical corrugated adhesive compositions. This allows a considerable reduction in the amount of alkali present. The borax can be present in any of several types or as an equivalent mixture of several types based primarily on the PH value of the composition. As mentioned above, the addition of alkali and borax to adhesive compositions is standard practice in the corrugated goods industry.

However, although compositions which do not contain these substances have also been used as corrugated body adhesives, it is preferred to add them together to the compositions according to the invention. Borax is commonly used to increase the gel structure of adhesive pastes.

However, excessive amounts of borax have an adverse effect on the cured bond strength. Additionally, borax increases the gelling temperature of the composition. have a tendency Generally up to about 5% borax (10 moles) is incorporated into the composition. Especially the customary amount is about 2
or about 3%. This percentage is based on the total starch material in the composition, including both the main active adhesive component and the carrier component. If 5 moles of borax are used instead of 10 moles, it is necessary to replenish the lost water of hydration. In carrier-free systems, boric acid can be used as a reaction terminator. Boric acid is quickly converted to borate and can then be used as a replacement for added borax. As used herein, the term "borax" includes all borates provided for the addition of boric acid. Any standard type of alkali can be used. However, for reasons of economy, sodium hydroxide is most commonly used. The alkali is used to lower the gelling temperature of the adhesive composition to the point where it can be easily manipulated. Generally this will range from about 145'P to below about 150, but in some applications from about 140 to 160'F. However, since alkali tends to reduce the formation of gel structure,
It is important that large amounts of alkali should not be added to any corrugated adhesive composition, whether conventional or in accordance with the invention. Generally up to about 5% alkali (calculated as sodium hydroxide) is used based on the total starch material in the system. In particular, amounts of about 3 to 3.5% are more commonly used. It is critical and critical that starch esters be used in at least sufficient amounts to essentially completely saponify them in the practice of this invention.

The amount of alkali mentioned above is the amount of alkali that exceeds the above minimum amount. The particular starch ester used in the practice of this invention is not critical, so long as it is saponified under the circumstances surrounding the corrugated body adhesive composition. Therefore, inexpensive and simple starch esters such as starch acetate are preferred. Particularly preferred are mixed esters such as starch acetate succinate. Starch esters are available as industrial products or can be prepared by any conventional method such as reacting unmodified starch with acid anhydrides, acid halides, vinyl esters, and the like. . The above reagents can also be used in carrying out the invention in its original embodiment. However, it is necessary that the esterification be carried out at a temperature below the practical gelation temperature of both the unmodified starch and the starch ester. Furthermore, the water content of the adhesive composition is
Adjustments should be made to obtain significantly tacky adhesive properties immediately after gelatinization.

This means that sufficient water must be present to complete gelatinization. It is most desirable that tackiness be developed quickly when heat is supplied in the corrugated body manufacturing apparatus. The amount of starch material used in the adhesive composition according to the invention is similar to that used in conventional compositions.

Generally, the granular starch component of Steinhall type compositions is about 10
Contains up to about 25% starch. The final adhesive mixture generally has about 12 to about 25% of the total starch in the form of a gelatinized carrier. The starch esters according to the invention can also be used as the carrier part of Steinhall type adhesives.

In such cases, the amount of carrier may be reduced somewhat because these starch esters are very viscous. The desired degree of substitution is based on the particular starch material chosen.

However, we have generally found it preferable to use saponifiable degrees of substitution of at least about 0.015. Saponifiable degree of substitution (D.S.
．． ) starch ester with Instron test 1 evaluation,
It has been found that the infrared diffraction results are satisfactory, allowing the machine to operate at speeds that are at least about 20% greater than those achieved using unmodified corn starch as the primary active adhesive composition. . Generally 0
．． Substitution levels greater than 0.015 allow the machine to operate at even faster speeds.

It has been found advantageous to use saponifiable starch esters having a degree of saponifiable substitution ranging from about 0.025 to about 0.045. The use of such materials generally allows corrugated body manufacturing machines to operate at speeds that are up to about 100% greater than those obtained using conventional adhesives. The green strength and the viscosity of the gelatinized corrugated adhesive that produces the green strength cannot be conveniently measured directly quantitatively in the precise context of bonding.

However, the inherent ability of corrugated body adhesives to produce even higher green strengths that improve the processing speed of the corrugated body is due to the primary active adhesive component selected for use in accordance with the present invention. It can be estimated by measuring the area under the Instronka hour curve of a paste made by a special method. The Instron-A time curve of the paste of the main active adhesive component can be measured by the following method.

Standard Instron Method Instron Tenzil Tester (InstrOnT
A compression load cell (CM) is installed on the tensile strength tester (tensile strength measuring instrument) model TT.

A culture tube approximately 22 mm in diameter and approximately 175 mm in height is placed in a constant temperature chamber. The chamber is a metal sleeve approximately 23 mm in diameter and 116 mm high, covered with approximately 4 feet of inch copper tubing, and covered with asbestos strapping. This copper tube is connected to the constant temperature bath by a suitable conductor tube. The starch slurry for testing is fed into the culture tube to a height of 2.75 inches. The culture tube is submerged into a sleeve that has been preheated with circulating water at a temperature of 210'F through a steel tube. 0
．． A thermopile probe having a diameter of 184 inches is inserted into the slurry to a depth of about 1 inch from the top surface.

The probe is inserted into the slurry at a rate of 0.02 inches/minute while the mechanical device and recorder are activated simultaneously. This heating cycle is allowed to continue for 14 minutes and then the hot water circulation is stopped. Then, after 1 minute, ice water is circulated through the copper tube for 15 minutes. The curve obtained in the recorder is called the Kerr time curve.

The first 15 minute fraction is the heating cycle, and the second 15 minute fraction is the cooling cycle. The test slurry used in the Instron method is manufactured as follows.

Add a predetermined amount of unmodified corn starch to 110 m
Treat with water from Step 1 to make a slurry.

Add a predetermined amount of 4% W/V borax (10 mol) solution and a predetermined amount of 20% W/V NaOH solution. Sufficient water is added so that the total amount added is 60 ml. The resulting slurry is heated to 212°C with stirring for 5 minutes and then allowed to stand for 5 minutes. This is then immediately added to the pre-prepared second slurry. The second slurry is made by treating 50V of test 1 starch in 165ml of water.

The first slurry is mixed with this slurry and the mixture is stirred for 15 minutes. It is then immediately tested on an Instron tester. Samples of unmodified corn starch were tested as test starches under these standard conditions.

Force-time heating and cooling curves were prepared as described above,
The area in each of these fractions was then measured separately. The above method is carried out on the starch material to be tested.

The area under the heating curve of the test starch is compared to that of unmodified cornstarch. The same thing is done for the area in the cooling curve. It must be emphasized that the areas in each fraction of the curve are treated independently of each other. The absolute area thus measured is an arbitrary value determined primarily by this test method. The critical feature of the test is not these absolute values, but the ratio of the area of the test starch to the area of unmodified cornstarch, conducted under the same test conditions.
This means that the predetermined amounts of carrier starch, borax and sodium hydroxide are the same. In addition, the above area ratio is actually expressed as a relative value by cutting out both curves obtained by measuring with an Instron Tenzil tester with scissors and comparing the weight of the cut paper. I can do it.

Although the Instron test cannot accurately obtain both the viscosity and gel structure on the bond line, it is a special, main adhesive property to realize a high degree of green strength in the surrounding situation of corrugated body bonding. It can provide a comparative measure of component performance.

In order to obtain the desired 20% improvement in machine operating speed, the ester material must have at least a It has been found that approximately 30% larger area must be exhibited.

In other words, saponifiable starch esters showing a 30% improvement in Instron values (larger area) based on both heating and cooling curves can be obtained using unmodified cornstarch when using the same equipment. A machine operating speed that is at least about 20% faster than the machine operating speed will be obtained. It is important that the starch ester has an overall saponifiable degree of substitution (DS) of at least about 0.015.

D. which can be saponified. S. The upper limit of is determined by economical and sensory considerations. The material also needs to have a gelling temperature high enough so that it does not gelatinize prior to use, for example during the manufacture of derivatives or adhesive compositions. . D. which can be saponified. S. The exact upper limit for is dependent on the particular substituent used, but is generally about 0.1 for esters of monocarboxylic acids and about 0.06 for monoesters of dicarboxylic acids.

It is known that under the conditions surrounding the adhesive composition, esters are saponified within a relatively short period of time. This means that the ester is essentially completely saponified before it is applied to the groove ridges. The exact structure of the saponified starch material is not known. It is probably complexed with either caustic alkali or borax commonly present in the system. It is believed that part of the improvement in machine operating speed is due to the lower level of alkali in the composition.

Some of the alkali is consumed as the ester is saponified. Some of the advantageous properties of starch esters are still retained in the saponified form.

In fact, the ester is essentially completely saponified before it is applied to the crests of the vertical grooves. It has been found that modified starch materials are produced by saponifying starch esters. Saponification is carried out in the presence of an alkali,
Furthermore, borax can also be included in the saponification medium. The modified material is then dried. This step, ie esterification followed by saponification, results in a material that is different from the original unmodified starch material. This modified substance is
It can be used in corrugated adhesive compositions in the same manner as starch esters are used. Improved green bond strength is obtained compared to unmodified cornstarch.
The exact mechanism of denaturation is not known, but probably physical disintegration of the granules or formation of small amounts of complexes between alkali and starch occur. The use of reduced amounts of alkali in corrugated body adhesive compositions does not contribute to improved machine operating speeds.

Even if the unmodified corn starch and the starch ester according to the invention are processed at exactly the same alkaline level,
Machine speeds are still significantly faster when using starch esters. Starch esters are used when producing adhesive compositions.
Formed in situ on a corrugated body processing machine.

Therefore, it is sufficient to simply add an ester-forming agent to the composition. The conditions are such that very rapid esterification takes place followed by irreversible saponification. Esterifying agents are conventional materials such as those mentioned above. The esterifying agent is added in such an amount that, if no saponification has already taken place, a product is produced with a saponifiable degree of substitution suitable for use according to the invention. Generally, reactants such as acetic anhydride have reaction efficiencies of about 50 to about 70% under conditions such as those obtained with corrugated adhesive compositions. The order of adding the above substances to the adhesive composition does not need to be exact in order to achieve the desired results.

Of course, it is necessary that the esterifying agent does not remain in the surrounding material for a period of time such that at least a portion of it decomposes. In order that the invention may be more fully understood, certain embodiments according to the invention are set forth and illustrated below. These are merely illustrative and descriptive of the invention, and the invention is not limited thereto.
Example 1 Manufacture of Comparative Corrugated Board To demonstrate that the corrugated adhesive according to the invention is an improvement over conventional unmodified starch Steinhall adhesive compositions, At higher speeds, prior art starch adhesives reach such limits that it is impossible to bond the corrugated boards sufficiently to prevent delamination during subsequent operations. and then to determine up to what machine operating speeds it is possible to produce corrugated boards using adhesives produced according to the invention without reaching the point of failure. is necessary.

The corrugated boards produced in this example test were all double hacker ports consisting of a 26 pound corrugated sheet located between two 42 pound kraft liners.

A commercially available double hacker corrugated body pode manufacturing equipment was used. All hot plate temperatures in this test were adjusted to 300'F. Initially, the adhesive supply gap of the adhesive supply device is set to 0.01.
I set it to 4 inches. A conventional corrugated adhesive of the Steinhall type and a corrugated adhesive composition according to the invention used as a control were prepared as shown in the table below. Conventional Double Hacker Composition Primary Mixer Added 10.0 gallons of water, added 20.0 pounds of unmodified cornstarch, 150'F
Heat to , add 3.3 pounds of NaOH dissolved in 2.0 gallons of water, stir for 15 minutes, add 10.0 gallons of cooling water, mix for 10 minutes and hold at 110'F'.

Added 30 gallons of 2nd mixer water and heated to 90'F, added 3.4 pounds of 10 mole borax, added 100 pounds of unmodified cornstarch, added 1st to 2nd over 30 minutes and 110' Adjust viscosity to 60 seconds with 4.5 gallons of water.

Double Hacker Composition According to the Invention First Mixer Added 10.0 Gallons of Water, Added 19.0 Ibs of Unmodified Cornstarch, 150'P
3.0 gallons of NaOH dissolved in 2.0 gallons of water.
Add 9 pounds, stir for 15 minutes, add 10.0 gallons of cooling water and maintain at 110'1:'.

Secondary mixer Added 30.0 gallons of water and heated to 90'F, added 1.5 pounds of 10 mole borax, starch acetate succinate (0.027 D.S. acetate, 0.02 D.S. succinate).
01D. S. ) Added 100 pounds, took 30 minutes to complete the first
Add the following to the second batch and hold at 110'F.

Stir for 5 minutes and add 1.5 lbs of 10 mole borax, 4 lbs of water.
．． Add 5 gallons and adjust viscosity to 60 seconds.

The adhesion of these compositions was determined as follows: Double Back Adhesion Both adhesive compositions were evaluated continuously on the same corrugating machine.

Using the control adhesive described above, the highest speed that a corrugated board could achieve in the cutting knife process on a corrugating machine before delamination began was 450 fpm.

Speeds of 600 feet per minute could be reached by using co-acetate starch as the raw starch portion of Steinhall's Double Hacker adhesive composition.

At this point, the adhesive gap on the double hacker feeder was increased from 0.014 inch to 0.016 inch and the corrugated body machine was operated at a speed of 700 feet per minute, as opposed to It is an additional 55% improvement compared to the 2000 double hacker green and has excellent double hacker green strength.
The single-facer one-corrugated body manufacturing machine is capable of bonding when the single-facer corrugated paper is supplied to the double hacker. It is not possible to maintain above this rate due to the inability of the machine to supply sufficient heat for the agent to gelatinize quickly enough. However, a double hacker process using a single facer bridge full width board manufactured at low machine speeds can achieve short-term operating speeds in excess of 800 feet per minute. These high speed limits occur when unbonded single facer sheets reach a double hacker bonding device. It is therefore clear that starch acetate succinate adhesives can produce good double hacker corrugated boards at corrugation speeds significantly in excess of 700 feet per minute. EXAMPLE 2 Corrugated Board Production Further corrugated body manufacturing tests were conducted using the same corrugated body making machine as in the method described in Example 1 and under essentially the same operating conditions.

Using this equipment, 0.013 inch and 0.014 inch
Boards were manufactured using 42 pounds of liner and 26 pounds of corrugated media with an inch adhesive gap. The starch derivative used as the main adhesive component has the following properties: it is acetate D. S. O. Oll; Succinate D. S. -0.015 starch acetate succinate.

Adhesive compositions prepared as described below could be operated at very high machine operating speeds with sufficient success. The composition is shown below: Machine operating speeds of 700 feet per minute were efficiently achieved in a primary 0.013 inch gap adhesive application.

80 by reducing the adhesive gap to 0.009 inch.
Sustained corrugation machine operating speeds in excess of 0 fpm were obtained. At this point the practical limit of the machine was reached and the 42 pound liner was replaced by the 62 pound liner. Using a heavier liner, the corrugated board was produced very efficiently at a speed of 650 fpm with the hot plate of the corrugated machine set at 350'F.

With conventional starch adhesives, when these liners are processed on the same machine, the temperature of the hot plate is 300-50
It showed a limit of 350-400 fpm at 0 fpm and below 350 fpm. When using the composition according to the invention, the efficiency of producing corrugated bodies is remarkable. Example 3 Additional manufacturing example in the process described in Example 2; primary adhesion using the same machine according to the process finally described in Steinhall Composition Example 2 using a 62 pound liner with the following properties: Additional tests were conducted using the ingredients:
The starch derivative defined as (a) was prepared in an adhesive composition as described in Example 2 and corrugated with a hot plate set at 300°C with an adhesive feed gap of 0.007 inch. used on board.

Initially, a machine operating speed of 600 fpm was obtained. 7 by opening the adhesive feed gap to 0.010 inch.
It was possible to reach speeds of up to 50 fpm. By increasing the hot plate temperature to below 350, an operating speed of 775 fpm was obtained and a satisfactory board was produced. By incorporating the starch derivative defined in (b) into the adhesive composition described in Example 2, a corrugated body making machine was prepared using a hot plate set at 350'F with a 0.007 inch adhesive gap. It was possible to produce a satisfactory corrugated board at a speed of 800 fpm by operating the .

Example 4 Starch acetate succinate (Acetate D.S.-0.0266; Succinate D.
．． S. -0.018) A small scale test was carried out using an adhesive composition (-1) containing 18-20%.

This corresponds in its composition to an 11-bag mixture of conventional single crusher standards (i.e., a composition containing 11 bags of adhesive component in approximately 650 gallons of total adhesive). be. For the second test, 2 out of 11 bags (i.e., approximately 18%) were unmodified cornstarch and the main adhesive component, and the remainder was the main adhesive component, based on a single crusher standard. An adhesive composition (-2) prepared from a mixture of the components in the following proportions was used.

The Steinhall viscosity of each of these compositions was measured after they were ready for use.

Methods for preparing these are described in U.S. This method is described in Japanese Patent No. 3,355,307 and is carried out as follows. Starch material 2507 is slurried in 890 ml of water at 105'F and 275 ml of 4% sodium hydroxide is added to the starch slurry over 4.5 minutes at room temperature. The reaction is then stopped with 4.77 boric acid at 600 cps. The paste obtained consists in each case of an essentially homogeneous suspension of partially swollen granules. Steinhall viscosity measurements are made immediately and then again after 24 hours of storage at 100'F with gentle agitation.

The viscosity was similar to a typical conventional composition. Viscosity of carrier-free adhesive composition Steinhall Typical conventional viscosity
(seconds) -1-2 Immediately after composition preparation 202020 After overnight storage 202020 Example 5 An adhesive composition was prepared having the following composition: average of both these grades of boards using the primary mixer adhesive. The speed is 200 fpm. It was hot.

The operating speed of the machine is not limited by adhesive failure in both of these cases, but may be limited by overloaded drives at even higher speeds. Example 7 25 ml of 2.75% (W/V) borax solution in a slurry of unmodified cornstarch 24.6 V in 330 ml of water
．． 45 ml of 0.09% (w/v) NaOH and a mixture of 0.018 mol of succinic anhydride and 0.048 mol of acetic anhydride were added.

Laboratory measurements of the resulting slurry showed that it had excellent adhesive properties. Example 8 In the method described in Example 7, adipic anhydride was substituted for succinic anhydride.

The product was also shown to be an excellent corrugated adhesive. Example 9 The following composition was used to manufacture a series of various products on a commercial basis.

Buri 1 υ Instronka time curve for the following starch substance? To this is added the primary mixer over a period of 30 minutes.

When using ester, NaOH is 20 lbs.
And the borax was increased to 18 pounds.

The compositions were tested in a series using a 60 pound liner with adhesive gaps set at 0.02 for single facer and 0.01 bi for double hacker. . ← was prepared according to standard methods.

Example 11 Standard Instron force-time area was measured for the following starch material.

Example 12 The material obtained in the manner described in Example 1 was saponified in the presence of NaOH and borax.

It is then washed with water to remove caustic soda, borax and salts. Instrocker times were measured using standard methods. This showed a heating cycle improvement of 58% and a cooling cycle improvement of 82%. Example 13 The process described in Example 12 was repeated using the material obtained in the process described in Example 5.

This showed a heating cycle improvement of 58% and a cooling cycle improvement of 102%. When an acid neutralization step is introduced into this,
No significant improvement over unmodified cornstarch was demonstrated.

Starch acetate succinate and other specific primary adhesive ingredients as defined herein give superior results when compared to unmodified corn starch and other conventional materials, but these It can be used to make corrugated body adhesive compositions in essentially the same proportions by general methods similar to those of the US Pat.

Generally, the main adhesive component of the present invention can be used in both Steinhall-type and carrier-free adhesive compositions, replacing a part or preferably all of the conventional main adhesive component. Certain changes in the amounts of the components and the addition of other ingredients can be made using these primary adhesive ingredients in the composition in the same manner as is done in conventional adhesive compositions. I can do it. Such changes are well known to those in the industry. Details of Steinhall adhesive systems are described in US Pat. Nos. 2,051,025 and 2,102,937, which are incorporated herein by reference.

Details of carrierless adhesive systems are described in US Pat. No. 3,355,307, which is incorporated herein by reference. If the novel compositions according to the invention are used in carrier-free compositions, reaction terminators such as acid anhydrides and acid chlorides are used. These are broadly defined as acids or acid-forming substances. By careful selection of the terminating agent, these can be used as terminating agents and esterifying agents. Of course, the final bond strength needs to be sufficiently high to be compatible with all conventional uses of the product when contrasted with the green bond strength of pin bonds. Tests have shown that the final bond strength using the adhesive composition according to the invention is essentially equivalent to the bond strength of conventional adhesives.

The adhesive composition according to the invention can of course be used for other applications besides producing corrugated paperboard.

It can be used, for example, in the production of tube rolls, laminates and multilayer paper bags. Additionally, conventional additives can be incorporated into the composition to impart water resistance to the cured composite. Although specific aspects of the present invention have been described above, in general, in accordance with the gist of the present invention, what is known or commonly used by those skilled in the field to which the present invention pertains, and which can be applied to the above gist. The invention is capable of variations, and modifications, uses or adaptations of the invention are possible within the scope of the invention, including changes that are within the scope of the invention.

Claims (1)

Claims: 1 Comprising at least two phases consisting of a carrier phase and a latent adhesive phase dispersed in said carrier phase, said latent adhesive phase comprising: (a) a non-waxy grain raw material; The resultant starch saponifiable starch ester has an area under an Instron force-time heating curve of at least about 30% greater and an Instron force- compared to unmodified cornstarch under the same test conditions. non-gelatinized having at least about 30% greater area under the time cooling curve;
granular saponifiable starch ester; and (b) suitable for use as a corrugated body adhesive, characterized in that it contains a sufficient amount of alkali to essentially completely saponify said saponifiable starch ester; An adhesive composition that can be used on a corrugated body making machine. 2 The starch ester that can be saponified is at least 0.015
The composition according to claim 1, having a saponifiable degree of substitution (D.S.) of . 3. The composition of claim 1, wherein the saponifiable starch ester acid is selected from the group consisting of starch acetate, starch succinate, starch acetate succinate, and mixtures thereof. 4. The composition of claim 1, wherein the saponifiable starch ester is corn starch acetate succinate having a degree of saponifiable substitution ranging from about 0.025 to about 0.045. 5 Based on the total amount of starch material on a commercial basis,
Added alkali up to about 5% and borax (up to about 5%)
10 mol).