阅读说明：本技术 一种瓦楞纸板复合用淀粉胶及其制备方法 (Starch glue for compounding corrugated boards and preparation method thereof ) 是由 何正陶 魏一勇 于 2021-09-11 设计创作，主要内容包括：本发明公开了一种淀粉胶领域,尤其是涉及一种瓦楞纸板复合用淀粉胶及其制备方法。瓦楞纸板复合用淀粉胶由质量比为1:1的载体淀粉与主体淀粉混合制得,所述载体淀粉至少包含如下质量份的组分：淀粉：4～8份；氢氧化钠：1～3份；水：50～80份；所述主体淀粉至少包含如下质量份的组分：淀粉：45～55份；硼砂：1～2份；水：120～150份；PAE树脂：3～8份；氨基硅烷偶联剂：0.5～1.5份；杀菌防腐剂：1～4份。本申请制得的淀粉胶在保持较高粘接强度的前提下,显著提高其防水性能。(The invention discloses the field of starch glue, and particularly relates to a starch glue for compounding corrugated boards and a preparation method thereof. The starch glue for compounding the corrugated board is prepared by mixing carrier starch and main starch in a mass ratio of 1:1, wherein the carrier starch at least comprises the following components in parts by mass: starch: 4-8 parts; sodium hydroxide: 1-3 parts; water: 50-80 parts; the main starch at least comprises the following components in parts by mass: starch: 45-55 parts of a solvent; borax: 1-2 parts; water: 120-150 parts; PAE resin: 3-8 parts; amino silane coupling agent: 0.5-1.5 parts; and (3) sterilization preservative: 1-4 parts. The waterproof performance of the starch glue prepared by the method is obviously improved on the premise of keeping higher bonding strength.)

1. The starch glue for compounding the corrugated boards is prepared by mixing carrier starch and main starch in a mass ratio of 1:1, and is characterized in that the carrier starch at least comprises the following components in parts by mass:

starch: 4-8 parts;

sodium hydroxide: 1-3 parts;

water: 50-80 parts;

the main starch at least comprises the following components in parts by mass:

starch: 45-55 parts of a solvent;

borax: 1-2 parts;

water: 120-150 parts;

PAE resin: 3-8 parts;

amino silane coupling agent: 0.5-1.5 parts;

and (3) sterilization preservative: 1-4 parts.

2. The starch glue for compounding corrugated boards as claimed in claim 1, wherein the bactericidal preservative is one or more of isothiazolinone, chitosan and polyhexamethylene guanidine hydrochloride.

3. The starch glue for compounding corrugated boards as claimed in claim 2, wherein the bactericidal preservative is a composition of isothiazolinone and chitosan in a mass ratio of 1 (2-3).

4. The starch glue for compounding corrugated boards as claimed in claim 1, wherein the main starch further comprises 2-3 parts by mass of a thickener.

5. The starch gum for compounding corrugated boards as claimed in claim 1, wherein the thickener is one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate and xanthan gum.

6. The starch glue for compounding corrugated boards as claimed in claim 1, wherein the main starch further comprises 0.5-1 part by mass of calcium bentonite.

7. The starch glue for compounding corrugated boards as claimed in claim 1, wherein the starch is one or more of corn starch, wheat starch and tapioca starch.

8. The method for preparing starch glue for compounding corrugated boards as claimed in any one of claims 1 to 7, which is characterized by comprising the following steps:

preparing carrier starch: heating water to 40-47 ℃, adding starch, stirring for 2-5 min, adding sodium hydroxide, heating to 65-75 ℃, continuing stirring for 30-60 min, and cooling to 40-50 ℃ to obtain carrier starch;

preparing main body starch: fully stirring water, starch, borax, PAE resin, a bactericidal preservative, an aminosilane coupling agent, a thickening agent and calcium bentonite to obtain main starch;

preparing starch glue: adding the carrier starch into the main starch, and uniformly mixing to obtain the starch.

Technical Field

The invention relates to the field of starch glue, in particular to a starch glue for compounding corrugated boards and a preparation method thereof.

Background

Corrugated board is formed by alternately compounding at least one layer of wavy core paper interlayer and corrugated paper (cardboard paper), has high mechanical strength and buffering effect, and is widely applied as a raw material of a packaging carton.

The wavy core paper and corrugated paper are compounded by starch glue, the raw materials of the starch glue mainly comprise plant starch and sodium hydroxide, and the starch is used as an adhesive, so that the wavy core paper has the advantages of high yield, low price, convenience in processing and the like. Sodium hydroxide is used as a pasting agent to reduce the pasting temperature and promote the starch to expand and paste to generate viscosity.

Although starch glue has a plurality of advantages, the starch glue has stronger water absorption due to more active groups such as hydroxyl groups and the like in molecules, and the phenomenon of glue failure is easily caused when the viscosity is reduced and the glue is seriously broken under the environment with higher humidity such as a freezer and the like.

Disclosure of Invention

In order to overcome the problems that the waterproof and anti-permeability performance of starch glue is poor, the viscosity is easy to decrease and even glue is easy to open, the application provides the starch glue for compounding the corrugated board and the preparation method thereof.

In a first aspect, the application provides a starch glue for compounding corrugated boards, which is prepared by mixing carrier starch and main starch in a mass ratio of 1:1, wherein the carrier starch at least comprises the following components in parts by mass:

starch: 4-8 parts;

sodium hydroxide: 1-3 parts;

water: 50-80 parts;

the main starch at least comprises the following components in parts by mass:

starch: 45-55 parts of a solvent;

borax: 1-2 parts;

water: 120-150 parts;

PAE resin: 3-8 parts;

amino silane coupling agent: 0.5-1.5 parts;

and (3) sterilization preservative: 1-4 parts.

The method adopts a two-step method to prepare starch glue, mixes partial starch with sodium hydroxide, and gelatinizes the mixture under a heating condition to obtain carrier starch (cooked slurry); meanwhile, the residual starch is mixed with borax and other substances to obtain main starch (raw slurry), and then the main starch is mixed with carrier starch, so that uncooked (gelatinized) starch particles in the main starch are suspended in the gelatinized cooked slurry to obtain starch glue. The gelatinized starch in the carrier starch provides the starch gum with initial viscosity and is capable of loading the ungelatinized host starch. After the starch glue is coated on the corrugated peak of the corrugated paper, high-temperature drying is needed, and at the moment, ungelatinized starch in the starch glue and water expand and gelatinize under the heated condition, so that viscosity is generated, and the core paper and the corrugated paper are firmly bonded.

In the pasting process, the borax can promote the cross-linking combination of starch molecules, increase the viscosity of starch glue and accelerate the bonding speed. According to the application, the PAE resin is added, active groups such as hydroxyl, amino and the like contained in the PAE resin are in cross-linking association with active groups such as hydroxyl and the like in starch molecules, so that the cross-linking density of the sizing material is effectively improved, the permeation of water vapor into the adhesive is inhibited, and the phenomenon that the bonding strength is reduced and even the adhesive is broken due to paste line emulsification is reduced.

However, the increase of the crosslinking density can cause the reduction of the starch adhesive property, which is not beneficial to reducing the glue failure phenomenon.

Preferably, the bactericidal preservative is one or more of isothiazolinone, chitosan and polyhexamethylene guanidine hydrochloride.

By adopting the technical scheme, the sterilization preservative can inhibit the breeding of bacteria and effectively prevent the viscosity from decreasing due to the degradation of gelatinized starch.

Preferably, the bactericidal preservative is a composition of isothiazolinone and chitosan in a mass ratio of 1 (2-3).

By adopting the technical scheme, the isothiazolinone has the antibacterial and bactericidal effects, and can effectively prevent the rubber material from deteriorating and the viscosity from decreasing. The chitosan not only can play a role in inhibiting bacteria, but also can promote the increase of the crosslinking density, further improve the hydrophobicity of the starch glue and reduce the phenomenon of glue failure. This may be because the cross-linked structure formed by cross-linking the PAE resin and starch has low strength, is easily broken by handling or vibration, and is not favorable for maintaining hydrophobicity. By adding chitosan, when the starch glue is dried at high temperature, the chitosan can be grafted on PAE molecules to form a firm mesh structure, so that the permeation of water vapor is reduced, and the glue failure phenomenon is reduced.

Preferably, the main starch further comprises 2-3 parts by mass of a thickening agent.

By adopting the technical scheme, the thickening agent is added, so that the viscosity of the starch glue can be effectively improved, and the glue opening phenomenon is reduced. The reason for this may be that the starch in the main starch is suspended in the starch glue in a granular form, but it is easily precipitated during the standing process, and the distribution is not uniform, so that the coated starch (not cured) is not uniformly distributed on the paste line, and the paste line where the starch granules are missing is easily poorly adhered and forms a gap when cured at high temperature, increasing the probability of moisture penetration. It is not favorable for improving the bonding strength and the waterproof performance. After thickening, the suspension stability of the starch granules can be improved, and the precipitation of the starch granules is reduced, so that the uniformity of viscosity of all parts of the paste line is promoted, and the bonding fastness is improved. Secondly, after the glue is applied, water in the starch glue is easy to permeate towards the paper direction, so that starch granules are difficult to be fully gelatinized, and the generation and growth of viscosity are not facilitated. More importantly, after thickening, the penetration loss of water to paper sheets can be inhibited, and the gelatinization is promoted to be fully performed, so that the core paper and the corrugated paper form firm adhesion.

Preferably, the thickening agent is one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate and xanthan gum.

By adopting the technical scheme, the carboxymethyl cellulose, the sodium carboxymethyl cellulose, the hydroxyethyl cellulose, the sodium alginate and the xanthan gum have good thickening effect, the suspension stability of starch particles is kept, the precipitation is reduced, and the loss of water is reduced. Finally, effectively improve corrugated container board complex firmness, reduce and split the gluey phenomenon.

Preferably, the main starch further comprises 0.5-1 part by mass of calcium bentonite.

By adopting the technical scheme, the sodium-based bentonite, the calcium-based bentonite and the lithium-based bentonite have better dispersibility and water absorbability, and can play roles of preventing precipitation and stably suspending starch particles when added into starch glue stock, thereby being beneficial to uniform and sufficient gelatinization of the starch particles on a paste line. Finally, the uniform distribution of starch granules is promoted, and the bonding fastness of the core paper and the corrugated paper is improved.

In the application, calcium bentonite is preferably adopted, and the inventor finds that when sodium alginate in the thickening agent is used together with the calcium bentonite, the starch glue can obtain more outstanding anti-settling performance, and the formation of starch viscosity is effectively promoted. The reason for this may be that sodium alginate can crosslink with calcium ions in calcium bentonite and form a network gel, significantly improving the suspension stability of starch particles, reducing sedimentation, and reducing loss of water.

Preferably, the starch is one or more of corn starch, wheat starch and cassava starch.

By adopting the technical scheme, the starch has better gelatinization stability and lower gelatinization temperature, and a better bonding effect is obtained after gelatinization.

In a second aspect, the application provides a preparation method of a starch glue for compounding corrugated boards, which comprises the following steps: preparing carrier starch: heating water to 40-47 ℃, adding starch, stirring for 2-5 min, adding sodium hydroxide, heating to 65-75 ℃, continuing stirring for 30-60 min, and cooling to 40-50 ℃ to obtain carrier starch;

preparing main body starch: fully stirring water, starch, borax, PAE resin, a bactericidal preservative, an aminosilane coupling agent, a thickening agent and calcium bentonite to obtain main starch;

preparing starch glue: adding the carrier starch into the main starch, and uniformly mixing to obtain the starch.

By adopting a two-step method, a small amount of starch is fully gelatinized under the heating condition and the action of sodium hydroxide to obtain carrier starch; and mixing most of the residual starch with other raw materials to prepare ungelatinized main starch, and suspending the main starch in the carrier starch after mixing the main starch with the carrier starch to obtain the starch glue. After the coating, the ungelatinized starch is fully expanded and gelatinized under high-temperature heating, so that firm bonding is formed, and the phenomenon of glue failure of the corrugated board is reduced.

In summary, the present application has the following beneficial effects:

1. through setting up PAE resin and aminosilane coupling agent in this application, can improve its waterproof performance when guaranteeing starch glue adhesion properties, reduce the possibility that starch glue is opened under the higher environment of humidity.

2. According to the application, the composition of isothiazolinone and chitosan is used as the bactericidal preservative, so that on one hand, the breeding of bacteria in starch glue is effectively inhibited, and the probability of glue material deterioration and viscosity reduction caused by putrefaction is reduced; on the other hand, the crosslinking density and strength are effectively improved, the waterproof and anti-permeability performance is enhanced, and the occurrence of the phenomenon of glue failure is favorably reduced.

3. By arranging the thickening agent and the calcium bentonite, the sedimentation of starch particles is effectively improved and reduced, and the distribution uniformity of the starch particles in starch glue is ensured; meanwhile, the penetration loss of water to the paper direction is reduced, the full gelatinization of starch is guaranteed, and finally, the adhesive strength of the corrugated board after compounding is improved, and the glue failure phenomenon is reduced.

Detailed Description

Examples

Example 1, a starch glue for compounding corrugated cardboard, the selection of each raw material component and the corresponding amount are shown in table 1, and the starch glue is prepared according to the following method:

preparing carrier starch: mixing 30% of water with sodium hydroxide, dissolving to obtain a sodium hydroxide solution, heating the rest water to 46 ℃, adding starch, stirring for 5min, adding the sodium hydroxide solution, heating to 73 ℃, continuing to stir for 40min, and cooling to 45 ℃ to obtain carrier starch;

preparing main body starch: stirring water, starch, borax, PAE resin, a sterilizing preservative, an aminosilane coupling agent, a thickening agent and calcium bentonite for 20min at normal temperature to obtain main starch;

preparing starch glue: adding the carrier starch into the main starch, mixing and stirring for 30min to obtain the starch glue.

Example 2, a starch glue for compounding corrugated cardboard, the selection of each raw material component and the corresponding amount thereof are shown in table 1, and the starch glue is prepared according to the following method:

preparing carrier starch: mixing 30% of water with sodium hydroxide, dissolving to obtain a sodium hydroxide solution, heating the rest water to 42 ℃, adding starch, stirring for 5min, adding the sodium hydroxide solution, heating to 68 ℃, continuing to stir for 60min, and cooling to 50 ℃ to obtain carrier starch;

preparing main body starch: stirring water, starch, borax, PAE resin, a sterilizing preservative, an aminosilane coupling agent, a thickening agent and calcium bentonite for 30min at normal temperature to obtain main starch;

preparing starch glue: adding the carrier starch into the main starch, and mixing and stirring for 20min to obtain the starch glue.

Examples 3 to 8, a starch glue for compounding corrugated boards, which is different from example 1 in that the selection of each raw material component and the corresponding amount thereof are shown in table 1.

Table 1, raw materials and amounts (kg) of starch glue for compounding corrugated boards in examples 1 to 8

In table 1, the starch is corn starch; the PAE resin is ft-688 obtained from a peaked environment-friendly material; the amino silane coupling agent adopts gamma-aminopropyl triethoxysilane; chitosan was obtained from southbound Yinda under the cat number 9012-76-4; the thickener is sodium alginate.

It should be noted that the above raw materials have no special requirements for manufacturers. Wherein the amino silane coupling agent adopts gamma-aminopropyl trimethoxy silane, N-2-aminoethyl-3-aminopropyl triethoxy silane, N-2-aminoethyl-3-aminopropyl trimethoxy silane and the like to obtain better bonding effect.

Example 9 is a starch glue for compounding corrugated cardboard, which is different from example 2 in that the same amount of sodium carboxymethylcellulose is used as the thickener.

Example 10 is a starch gum for compounding corrugated cardboard, which is different from example 2 in that equal amounts of carboxymethyl cellulose and xanthan gum are used as thickeners, and the mass ratio of carboxymethyl cellulose to xanthan gum is 1: 1.

Example 11 is a starch glue for compounding corrugated cardboard, which is different from example 2 in that an equal amount of sodium bentonite is used instead of calcium bentonite.

Example 12, a starch glue for compounding corrugated cardboards, which is different from example 2 in that corn starch is replaced with tapioca starch in the same amount.

Comparative example

Comparative example 1, a starch glue for compounding corrugated cardboards, which is different from example 1 in that the same amount of starch was used in the main starch instead of the PAE resin.

Comparative example 2, a starch glue for compounding corrugated cardboards, which is different from example 1 in that the same amount of starch is used in the main starch instead of the aminosilane coupling agent.

Comparative example 3, a starch glue for compounding corrugated cardboards, is different from example 1 in that the same amount of starch is used in the main starch instead of the PAE resin and the aminosilane coupling agent.

Performance test

Test 1: starch glue tack test

The test method comprises the following steps: (1) the starch glue prepared in the above examples and comparative examples is taken for compounding the corrugated board according to the following process: the corrugated board is obtained by adopting raw paper with the gram weight of 160 g/square meter and performing pressing corrugation, gluing, drying, cooling, shaping and slitting by using a single-sided corrugating machine. Wherein the drying is carried out by three-stage steam heating at 170 + -3 deg.C, 190 + -3 deg.C, 170 + -3 deg.C, and 175 + -3 deg.C.

(2) The corrugated cardboard obtained as described above was subjected to an adhesive strength (N/m) test in accordance with the standards and regulations in GB/T6548-.

Test 2: starch glue water resistance test

The test method comprises the following steps: taking the corrugated boards of the same batch prepared in the step (1), placing the corrugated boards in a freezer with the temperature of 5 +/-2 ℃ and the relative humidity of 75 +/-5% for standing for 7d, taking out the corrugated boards, and measuring the bonding strength of the corrugated boards according to the method in the test 1. Each set of examples or comparative examples was measured 5 times, and the average value was taken, and the test results are shown in Table 2.

TABLE 2, test 1 and test 2 test results (N/m)

And (3) analyzing test results:

(1) by combining examples 1 to 12 and comparative examples 1 to 3 and table 2, it can be seen that the water resistance of the starch adhesive can be remarkably improved on the premise of ensuring the bonding strength of the starch adhesive by adopting the PAE resin and the aminosilane coupling agent together. The PAE resin molecules contain more active groups such as hydroxyl, amino and the like, and the active groups can be in cross-linking association with the active groups such as hydroxyl and the like in the starch molecules, so that the cross-linking density of the glue layer is improved, the permeation of water vapor into the adhesive is effectively inhibited, and the phenomena of bonding strength reduction and even glue failure caused by paste line emulsification are reduced. And amino group at one end of a molecular chain of the amino silane coupling agent can be bonded with an active group in the starch glue, and siloxane group at the other end is bonded with an active group of paper sheet fiber after being hydrolyzed, so that the bonding strength of the starch glue and the paper sheet is remarkably improved, and the reduction of the bonding strength caused by the increase of the crosslinking density is compensated.

(2) By combining the embodiment 2 and the embodiments 5 to 6 and combining the table 2, it can be seen that the bactericidal preservative prepared by compounding the isothiazolinone and the chitosan is beneficial to improving the waterproof performance of the starch glue. The reason for this is probably that isothiazolinone has outstanding bactericidal and bacteriostatic properties, can inhibit the breeding of bacteria, and effectively prevent starch from deteriorating and decomposing to reduce viscosity; the chitosan has an antibacterial effect and can react with an epoxy chloropropane chain in the PAE resin, so that the chitosan is grafted on a molecular chain of the PAE resin to form a certain network structure, the crosslinking density and strength are increased, and the hydrophobicity of a glue layer is favorably improved.

(3) By combining the embodiment 2 and the embodiments 7 to 11 and combining the table 2, it can be seen that the bactericidal preservative prepared by compounding the thickening agent and the bentonite is beneficial to improving the bonding strength and the waterproof performance of the starch adhesive, the bentonite adopts calcium bentonite, and the effect obtained by adopting sodium alginate as the thickening agent is more excellent. The thickening agent and the bentonite have thickening effects, so that precipitation of immature starch particles in main starch is reduced, uniform distribution of the immature starch particles is promoted, permeation and loss of water to paper sheets are reduced, full gelatinization of the starch is promoted, firm and compact bonding is formed, gap structures and poor bonding in bonding lines are reduced, and water resistance and impermeability are improved.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.