CN111349409B

CN111349409B - Preparation process of corrugated board starch adhesive

Info

Publication number: CN111349409B
Application number: CN202010236637.6A
Authority: CN
Inventors: 索艳格; 王召霞; 孙俊军; 黄煜琪; 张治国
Original assignee: Zhejiang Lover Health Science and Technology Development Co Ltd; Zhejiang Great Shengda Packing Co Ltd
Current assignee: Zhejiang Lover Health Science and Technology Development Co Ltd; Zhejiang Great Shengda Packing Co Ltd
Priority date: 2020-03-30
Filing date: 2020-03-30
Publication date: 2021-08-10
Anticipated expiration: 2040-03-30
Also published as: CN111349409A

Abstract

The invention provides a preparation process of a corrugated board starch adhesive, which comprises the following steps: step one, preparing cooked slurry: adding water and starch in sequence into a hydrapulper, uniformly stirring for 15 minutes, adding sodium hydroxide, alkali lignin and pulp fiber in sequence, and stirring for 1-2 hours to enable the starch, the sodium hydroxide, the alkali lignin and the pulp fiber to fully act until the starch, the alkali lignin and the pulp fiber are completely cured; step two, preparing a main body slurry: adding water into a reaction kettle under a stirring state, adding starch, stirring for 1 hour, sequentially adding low-carbon aldehyde and hydrogen peroxide, and stirring and reacting for 2 hours at the temperature of 30-50 ℃; step three, preparing a starch adhesive: continuously and uniformly stirring the prepared main body pulp, slowly adding the prepared cooked pulp into the main body pulp, and fully stirring and mixing the prepared cooked pulp and the prepared main body pulp; adding a rheological regulator, stirring uniformly, and reacting for 30-60 minutes at 30-50 ℃; then adding urea and sodium bentonite in turn and stirring for 10-30 minutes. The invention adopts the mixed reaction process of the main body slurry and the raw slurry, and the prepared adhesive has good bonding strength.

Description

Preparation process of corrugated board starch adhesive

Technical Field

The invention relates to the technical field of adhesives. More specifically, the invention relates to a preparation process of corrugated board starch glue.

Background

With the development of the packaging industry, the use amount and the research and development of 4 large pillars of paper, plastic, metal and glass, which are used as packaging materials of modern commodities, are greatly increased, wherein the yield of paper products is increased fastest and the proportion of the paper products is the largest. Corrugated paper boards in paper products are widely applied to commodity packaging due to excellent protection and shockproof functions and low price.

Corrugated cardboard is a multi-layer adhesive body, which is composed of at least one layer of wavy core paper interlayer (commonly known as "hole paper", "corrugated core paper", "corrugated paper core", "corrugated raw paper") and one layer of cardboard (also known as "cardboard paper" and "linerboard"), and is mainly used for manufacturing paper boxes, the sandwich of paper boxes and other packaging materials of fragile goods. The corrugated board is not only a recyclable environment-friendly material composed of wood fibers which can be decomposed by natural action, but also can be recycled without affecting the performance of the corrugated board, and the corrugated board (box) is a green environment-friendly packaging product acknowledged all over the world.

With the continuous development of the times and the continuous updating of production technology and equipment, the more sophisticated equipment technology and the more diversified market demands of people, the demand of corrugated boards is increasingly expanded by a considerable geometric multiple. The development prospect looks like a bright scene, and the former way is endless. However, in the present day that market competition is getting stronger, science and technology are continuously updated, and new packaging materials are continuously developed, corrugated boards are required to keep the situation of 'one go' in the packaging materials, and further improvement and development are required in the aspects of research and development of technical equipment, improvement of quality and performance, enrichment of product types and the like.

Starch adhesive is increasingly paid attention to people as one of main auxiliary materials for corrugated board production. The starch adhesive is a natural adhesive prepared by taking starch as a base material. The starch can be processed into soluble starch, dextrin, hydroxyethyl ether starch and other forms by physical and chemical methods, and can be matched with corresponding additives to prepare starch adhesives with different viscosities, solid contents, appearances and mechanical properties according to different application requirements. Starch adhesive belongs to vegetable gum and is widely applied to the industries of textile, papermaking, medicine, food, packaging and the like.

The industrial starch glue is prepared by using corn as raw material, dispersing corn starch in water, heating or adding small amount of caustic soda to gelatinize the starch, and diluting with water to obtain common corn starch glue. When the starch glue is actually prepared, 0.2 to 2 percent of borax based on the mass of starch is usually added to play a role in mildew prevention, crosslinking and toughening, and the water resistance and the mould resistance can also be improved, and 0.5 to 3 percent of formaldehyde or phenol is added as a preservative in some cases; some of them are added with glycerol, ethylene glycol and the like as plasticizers. To further improve the utility of the starch glue, it may also be modified with polyvinyl alcohol, urea formaldehyde resin, resorcinol-formaldehyde resin (see phenolic resin) or isocyanates.

However, the currently produced starch adhesives usually use borax as a cross-linking agent, and the borax is toxic and has great harm to human bodies. In 2010, the European Union REACH regulation lists three types of boron-containing substances as high-interest Substances (SVHC), which causes that a plurality of products in China cannot enter the European market due to the problems of packaging and the like, and brings little impact to the export market in China.

Disclosure of Invention

As a result of a variety of extensive and intensive studies and experiments, the inventors of the present invention have found that low carbon aldehydes can preliminarily modify starch in a body slurry, achieving the purpose of improving the starch crosslinking effect through an aldol condensation reaction; and the paper pulp fiber is a fiber with high strength, has huge specific surface area and abundant active hydroxyl groups, and after full reaction, the cellulose fiber can be fully dispersed in the adhesive, so that the adhesive force is greatly improved. Based on this finding, the present invention has been completed.

An object of the present invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.

It is also an object of the present invention to provide a better insulation and crack resistance by adding pulp fiber due to its dimensional and thermal stability.

To achieve these objects and other advantages in accordance with the present invention, there is provided a process for preparing a starch adhesive for corrugated cardboards, comprising the steps of:

step one, preparing cooked slurry: sequentially adding 300 parts of water and 30 parts of starch into a hydrapulper, uniformly stirring for 15 minutes, sequentially adding 10-20 parts of sodium hydroxide, 10-20 parts of alkali lignin and 5-10 parts of pulp fiber, and stirring for 1-2 hours to fully react the starch with the sodium hydroxide, the alkali lignin and the pulp fiber until the starch is completely cured;

step two, preparing a main body slurry: adding 400 parts of 300-400 parts of water into a reaction kettle under the stirring state, adding 100 parts of starch, stirring for 1 hour, sequentially adding 2-6 parts of low-carbon aldehyde and 3-8 parts of hydrogen peroxide, and stirring and reacting for 2 hours at the temperature of 30-50 ℃;

step three, preparing a starch adhesive:

continuously and uniformly stirring the main body slurry prepared in the step two, and slowly adding the cooked slurry prepared in the step one into the main body slurry to fully stir and mix the main body slurry and the cooked slurry; then adding 2-4 parts of rheological regulator, stirring uniformly, and reacting for 30-60 minutes at 30-50 ℃; then adding 1-3 parts of urea and 1-3 parts of sodium bentonite in sequence and stirring for 10-30 minutes.

Preferably, wherein the starch is at least one selected from the group consisting of corn starch, tapioca starch and potato starch.

Preferably, wherein the starch is corn starch.

Preferably, the lower aldehyde is at least one selected from glyoxal, glutaraldehyde and adipaldehyde.

Preferably, wherein the lower aldehyde is glyoxal.

Preferably, the rheology regulator is one of sodium tripolyphosphate, ferric chloride, ferric sulfate, alum and aluminum sulfate.

Preferably, wherein the stirring temperature in the preparation process of the main body slurry is 40 ℃.

The invention at least comprises the following beneficial effects:

1. the raw materials are safe and nontoxic, meet the environmental protection requirement, and the process is simple and controllable;

2. the preparation process of mixing and reacting the cooked pulp and the main body pulp is adopted, the stirring time is determined by monitoring the viscosity, the initial adhesion force of the starch in a low-temperature state is ensured, and the corrugated board starch adhesive has good adhesive strength;

3. the low-carbon aldehyde improves the starch crosslinking effect, and the alkali lignin added in the preparation of the cooked slurry stabilizes the viscosity and the binding power of the starch adhesive; meanwhile, due to the introduction of a proper amount of paper pulp fibers, the cellulose fibers are dispersed in the adhesive after fully reacting, so that the bonding force is greatly improved, and the bonding strength and the surface strength are obviously improved due to the capillary action of a fiber structure;

4. the addition of ferric chloride, ferric sulfate, alum, aluminum sulfate and sodium tripolyphosphate as a rheological regulator can realize further complexation reaction on starch molecules, improve the crosslinking effect and realize stable complexation between lignin molecules and starch molecules.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Detailed Description

The present invention is described in further detail below to enable those skilled in the art to practice the invention with reference to the description.

It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.

Example 1:

step one, preparing cooked slurry: adding 300 parts of water into a hydrapulper, adding 30 parts of starch, uniformly stirring for 15 minutes, then adding 10 parts of sodium hydroxide, adding 10 parts of alkali lignin and then 5 parts of paper pulp fiber, stirring for 1 hour in the hydrapulper, and fully acting the starch, the sodium hydroxide, the alkali lignin and the paper pulp fiber to be fully cured to form cooked pulp;

step two, preparing a main body slurry: in another reaction kettle, adding 300 parts of water and 100 parts of corn starch under stirring, stirring for 1 hour, then adding 2 parts of glyoxal and 3 parts of hydrogen peroxide, continuously stirring and reacting for 2 hours at 30 ℃, and stirring for later use;

step three, preparing a starch adhesive:

continuously and uniformly stirring the main body slurry prepared in the step two, and slowly adding the cooked slurry prepared in the step one into the main body slurry to fully stir and mix the main body slurry and the cooked slurry;

then adding 2 parts of sodium tripolyphosphate, stirring uniformly, controlling the reaction temperature to be 30 ℃, and stirring for reaction for 60 minutes;

adding 1 part of urea, adding 1 part of sodium bentonite, stirring for 10 minutes, and putting the obtained starch adhesive into a storage tank for production and use.

The gelatinization temperature of the obtained adhesive is 55 ℃, the viscosity is 26s, the initial adhesion time is 1.6 minutes, and the adhesion strength is 855N/m; the water resistance of the adhesive is more than 24 hours, the steam pressure used by a corrugated board production line is 5 kilograms, and the normal high-speed production can be realized at the temperature of 140 ℃.

Example 2:

step one, preparing cooked slurry: adding 300 parts of water into a hydrapulper, adding 30 parts of starch, uniformly stirring for 15 minutes, then adding 20 parts of sodium hydroxide, adding 20 parts of alkali lignin and 10 parts of paper pulp fibers, and stirring for 2 hours in the hydrapulper to fully react and completely cure the starch, the sodium hydroxide, the alkali lignin and the paper pulp fibers to form cooked pulp;

step two, preparing a main body slurry: in another reaction kettle, adding 400 parts of water and 100 parts of cassava starch under stirring, stirring for 1 hour, then adding 6 parts of glutaraldehyde and 8 parts of hydrogen peroxide, continuously stirring for reaction for 2 hours at 50 ℃, and stirring for later use;

step three, preparing a starch adhesive:

then adding 4 parts of ferric chloride, uniformly stirring, controlling the reaction temperature to be 50 ℃, and stirring for reaction for 30 minutes;

adding 3 parts of urea, adding 3 parts of sodium bentonite, stirring for 30 minutes, and putting the obtained starch adhesive into a storage tank for production and use.

The gelatinization temperature of the obtained adhesive is 49 ℃, the viscosity is 18s, the initial adhesion time is 1.0 minute, and the adhesion strength is 930N/m; the water resistance of the adhesive is more than 36 hours, the steam pressure used by a corrugated board production line is 4 kilograms, and the normal high-speed production can be realized at the temperature of 130 ℃.

Example 3:

step one, preparing cooked slurry: adding 300 parts of water into a hydrapulper, adding 30 parts of starch, uniformly stirring for 15 minutes, then adding 15 parts of sodium hydroxide, adding 15 parts of alkali lignin and 7 parts of paper pulp fibers, and stirring for 2 hours in the hydrapulper to fully react and completely cure the starch, the sodium hydroxide, the alkali lignin and the paper pulp fibers to form cooked pulp;

step two, preparing a main body slurry: in another reaction kettle, adding 350 parts of water and 100 parts of potato starch under stirring, stirring for 1 hour, then adding 4 parts of adipaldehyde and 5 parts of hydrogen peroxide, continuously stirring and reacting for 2 hours at 40 ℃, and stirring for later use;

step three, preparing a starch adhesive:

adding 3 parts of ferric sulfate, uniformly stirring, controlling the reaction temperature to be 40 ℃, and stirring for reaction time of 45 minutes;

adding 2 parts of urea, adding 2 parts of sodium bentonite, stirring for 20 minutes, and putting the obtained starch adhesive into a storage tank for production and use.

The gelatinization temperature of the obtained adhesive is 48 ℃, the viscosity is 19s, the initial adhesion time is 1.1 min, and the adhesion strength is 980N/m; the water resistance of the adhesive is more than 48 hours, the steam pressure used by a corrugated board production line is 4 kilograms, and the normal high-speed production can be realized at the temperature of 130 ℃.

Example 4:

step one, preparing cooked slurry: adding 300 parts of water into a hydrapulper, adding 30 parts of starch, uniformly stirring for 15 minutes, then adding 12 parts of sodium hydroxide, adding 10 parts of alkali lignin and 6 parts of paper pulp fiber, stirring for 2 hours in the hydrapulper, and fully acting and completely curing the starch, the sodium hydroxide, the alkali lignin and the paper pulp fiber to form a cured pulp;

step two, preparing a main body slurry: in another reaction kettle, adding 300 parts of water and 100 parts of corn starch under stirring, stirring for 1 hour, then adding 3 parts of glyoxal and 5 parts of hydrogen peroxide, continuously stirring and reacting for 2 hours at 40 ℃, and stirring for later use;

step three, preparing a starch adhesive:

adding 3 parts of alum, stirring uniformly, controlling the reaction temperature to be 40 ℃, and stirring for 45 minutes;

adding 1 part of urea, adding 1 part of sodium bentonite, stirring for 20 minutes, and putting the obtained starch adhesive into a storage tank for production and use.

The gelatinization temperature of the obtained adhesive is 51 ℃, the viscosity is 22s, the initial adhesion time is 1.2 minutes, and the adhesion strength is 890N/m; the water resistance of the adhesive is more than 48 hours, the steam pressure used by a corrugated board production line is 5 kilograms, and the normal high-speed production can be realized at the temperature of 140 ℃.

Example 5:

step three, preparing a starch adhesive:

then adding 2 parts of aluminum sulfate, uniformly stirring, controlling the reaction temperature to be 40 ℃, and stirring for 45 minutes;

The gelatinization temperature of the obtained adhesive is 47 ℃, the viscosity is 18s, the initial adhesion time is 0.9 min, the adhesion strength is 960N/m, the water resistance of the adhesive is more than 48 h, the steam pressure used by a corrugated board production line is 4 kg, and the high-speed production can be normally carried out at the temperature of 130 ℃.

The corrugated board starch adhesive prepared by the embodiments of the invention has the water resistance of more than 24 hours, the gelatinization temperature of less than 55 ℃, the steam pressure used by a corrugated board production line of only 4-5 kg and the temperature of 130-140 ℃, and can realize normal high-speed production, the corrugated board starch adhesive is used for corrugated board production, and the bonding strength of the prepared corrugated board exceeds 850N/m.

The production process of the corrugated board glue is simple and controllable, the raw materials are safe and nontoxic, the use of toxic and harmful borax is avoided in the process, and the most advanced environment-friendly requirement is met; and the preparation process of mixing and reacting the main body pulp and the cooked pulp is adopted, and the stirring time is determined by monitoring the viscosity, so that the initial adhesion of the starch in a low-temperature state is ensured, and the corrugated board glue has good adhesion strength.

The low-carbon aldehyde such as glyoxal, glutaraldehyde, hexanedial and the like can carry out primary modification on the starch in the main body slurry, and the aim of improving the starch crosslinking effect is fulfilled through aldol condensation reaction; in the preparation of the cooked slurry, alkali lignin is added, the substance becomes lignin glue after being cured under the process condition of the invention, the lignin glue and starch molecules are fully mixed and contacted, and the viscosity and the binding power of the starch glue are stabilized through the interaction of a large number of polar groups; simultaneously, due to the introduction of a proper amount of paper pulp fibers, cellulose is high-strength fibers and has huge specific surface area and abundant active hydroxyl groups, and after full reaction, the cellulose fibers can be fully dispersed in the adhesive, so that the adhesive force is greatly improved, the fibers can increase the adhesion of starch glue and various mineral substances on the surfaces of paper and paper, and the adhesive force between mixed materials is improved; due to the capillary action of the fiber structure, moisture in the system is rapidly transmitted to the surface and the interface of the slurry, so that the moisture in the slurry is uniformly distributed, the skinning phenomenon is obviously reduced, the bonding strength and the surface strength are obviously improved, the tension is reduced in the drying process by the mechanism, the anti-cracking effect is obviously achieved, and the dimensional stability and the thermal stability of the wood fiber also have good heat-insulating anti-cracking effect.

According to the invention, one of ferric chloride, ferric sulfate, alum, aluminum sulfate and sodium tripolyphosphate is added as a rheological regulator, so that further complexation reaction on starch molecules can be realized, the crosslinking effect is improved, and stable complexation between lignin molecules and starch molecules is realized, mainly because the substances have strong complexation capability and can be stably maintained in the adhesive system.

The addition of the urea further realizes the quaternary complex of the starch, the lignin, the metal atoms and the urea, realizes the stable and controllable viscosity of the starch adhesive, improves the storage and application stability of the adhesive, and can also improve the water resistance of the product.

While embodiments of the invention have been disclosed above, it is not intended to be limited to the uses set forth in the specification and examples. It can be applied to all kinds of fields suitable for the present invention. Additional modifications will readily occur to those skilled in the art. The invention is therefore not to be limited to the specific details described herein, without departing from the general concept as defined by the appended claims and their equivalents.

Claims

1. A preparation process of a corrugated board starch adhesive is characterized by comprising the following steps:

step three, preparing a starch adhesive:

continuously and uniformly stirring the main body slurry prepared in the step two, and slowly adding the cooked slurry prepared in the step one into the main body slurry to fully stir and mix the main body slurry and the cooked slurry; then adding 2-4 parts of rheological regulator, stirring uniformly, and reacting for 30-60 minutes at 30-50 ℃; the rheological regulator is one of sodium tripolyphosphate, ferric chloride, ferric sulfate, alum and aluminum sulfate; then adding 1-3 parts of urea and 1-3 parts of sodium bentonite in sequence and stirring for 10-30 minutes.

2. The process for preparing a corrugated board starch adhesive as claimed in claim i, wherein the starch is at least one selected from the group consisting of corn starch, tapioca starch and potato starch.

3. A process for preparing a corrugated board starch adhesive as claimed in claim 2, wherein the starch is corn starch.

4. The process I for preparing a starch adhesive for corrugated boards according to claim l, wherein the low carbon aldehyde is at least one selected from glyoxal, glutaraldehyde and adipaldehyde.

5. The process for preparing a corrugated board starch adhesive according to claim l, wherein the low carbon aldehyde is glyoxal.

6. A process for preparing a corrugated board starch adhesive as claimed in claim I, wherein the stirring temperature in the process for preparing the body paste is 40 ℃.