JPH08296193A - Production of paper board - Google Patents

Abstract

PURPOSE: To produce a paper board having improved internal tearing strength of the board without deteriorating the operability by adding an amphoteric starch polyion complex to a pulp slurry and making a paper board from the slurry. CONSTITUTION: An amphoteric starch polyion complex is produced by mixing (A) 80-20wt.% of a cationic starch having a substitution degree of 0.02-0.07 and cationized with at least one kind of cationizing agent selected from diethylaminoethyl chloride, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride and 2,3-epoxypropyl trimethyl ammonium chloride and (B) 20-80wt.% of an anionic starch having a substitution degree of 0.01-0.05 and produced by one or more means selected from oxidization, ureaphosphorylation, maleinization and succinization, e.g. a ureaphosphorylated starch having a bonded phosphorus content of 0.1-1.0wt.% and gelatinizing the mixture by adjusting the pH to 3-6. The amphoteric starch polyion complex is added to a pulp slurry in an amount of 1.0-10.0wt.% based on the dry weight of the pulp and a paper board is produced from the slurry.

Description

Detailed Description of the Invention

[0001]

[Industrial applications]

The present invention relates to a method for producing paperboard, and more particularly to a method for producing paperboard such as a core, liner, white paperboard, etc., having increased internal strength.

[0003]

[Prior art]

[0004] Paperboards such as cores, liners or white paperboards are industrial basic materials which are processed into corrugated cardboard or paper containers and used for packaging and transporting various articles.

These materials are required to have paper internal strength such as burst strength, tensile strength and compressive strength depending on their use.

[0006] To meet these demands, as a conventional method for producing a paperboard for increasing the internal strength, a method of using pulp having a high strength as a raw material, a synthetic polymer paper such as polyacrylamide as a paper material at the time of papermaking A method of adding a strength enhancer, a method of spraying an aqueous suspension of starch on a wet paper made into paper, and the like are known, and some have been put to practical use.

[0007]

[Problems to be Solved by the Invention]

However, each of the above-mentioned conventional paperboard manufacturing methods has the following problems to be solved.

That is, of the above-mentioned paperboard manufacturing methods, the method of using high-strength pulp is disadvantageous in terms of economy because expensive paper is used because the waste paper material is mainly contained in the paperboard. In addition to this, there are problems such as going against the recent demand for saving resources.

In addition, the method of adding polyacrylamide or the like to the paper material makes it difficult to recover broke or waste paperboard because the disintegration property when the paperboard is recycled decreases.
The affinity between corrugated cardboard adhesives and polyacrylamide is relatively poor, and it is difficult to obtain bonding speed and adhesive strength, so there is a problem that the liner and core core paper, which are corrugated cardboard base papers, have poor bonding properties. To do.

Further, the starch spray method is good in sticking property and disintegration property, but is easily soiled on the paper machine due to scattering of fog droplets.
There is a problem in terms of operability.

As described above, since the conventional paperboard manufacturing method has advantages and disadvantages, there has been a strong demand in the industry for a paperboard manufacturing method that solves these problems.

Therefore, an object of the present invention is to provide a paperboard which is excellent in disintegration property and laminating property and which has improved internal strength of the paper without impairing the operability of a machine used for manufacturing a paper machine or the like. An object of the present invention is to provide a method for producing paperboard that can be produced economically.

[0014]

[Means for Solving the Problems]

As a result of earnest studies with the above objects, the inventors have found that the above problems can be solved by adding a zwitterionic starch polyion complex to a pulp slurry for papermaking, and to complete the present invention. I arrived.

That is, the means for solving the problems of the present invention are as follows.

First, a method for producing paperboard, which comprises adding a zwitterionic starch polyion complex to a pulp slurry for papermaking.

Secondly, a method for producing paperboard, which comprises adding a zwitterionic starch polyion complex comprising a mixture of a cationic starch and an anionic starch to a pulp slurry to make a paper.

Thirdly, a zwitterionic starch polyion complex comprising a mixture of 80 to 20% by weight of cationic starch and 20 to 80% by weight of anionic starch is added to the pulp slurry for papermaking. And a method for manufacturing paperboard.

Fourth, the cationic starch is cationized with at least one cationizing agent selected from diethylaminoethyl chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-epoxypropyltrimethylammonium chloride. The anionic starch is oxidized, urea phosphorylated,
The method for producing paperboard according to the third aspect, which is anionized by at least one means selected from maleic acid esterification and succinic acid esterification.

Fifth, the cationic starch has a substitution degree of 0.0
2 to 0.07, and the anionic starch is
The method for producing paperboard according to the third aspect, which is a urea phosphorylated starch having a bound phosphorus content of 0.1 to 1.0% by weight.

Sixth, the cationic starch has a substitution degree of 0.0.
2 to 0.07, and the anionic starch is
The above third having a degree of substitution of 0.01 to 0.05
The method for producing a paperboard according to.

Seventh, an aqueous suspension of zwitterionic starch having a pH adjusted to 3 to 6 is gelatinized by a continuous gelatinizer to form a zwitterionic starch polyion complex, and the zwitterionic starch is prepared. A method for producing paperboard, which comprises adding a polyion complex to a pulp slurry for papermaking.

Eighth, a method for producing paperboard, characterized in that the amphoteric starch polyion complex is added to the pulp slurry in an amount of 1.0 to 10.0% by weight based on the dry-dry weight of the pulp to make paper. .

When forming the zwitterionic starch polyion complex used in the present invention, 80 to 20% by weight of the cationic starch powder and 20 to 80% by weight of the anionic starch powder are mixed in advance. In addition to the suspension of the powder mixture in water, it is possible to use a suspension of the cationic starch of the above distribution and the anionic starch of the above distribution while mixing.

Less than 20% by weight of anionic starch or 80
When it exceeds the weight%, the effect of improving the internal strength peculiar to the present invention cannot be obtained, which is not preferable.

As the cationic starch, raw starch produced from potato, tapioca, corn, wheat and the like is reacted with a cationizing agent which is a tertiary amine or a quaternary ammonium salt in an aqueous suspension, or powdered Those obtained by mixing the cationizing agent as it is and reacting it in a dry manner can be suitably used.

As the cationizing agent, diethylaminoethyl chloride hydrochloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,2
3-Epoxypropyl trimethyl ammonium chloride is mentioned as an example of a suitable thing, and these cationizing agents can be used individually or in combination of 2 or more types.

Examples of the anionic starch include oxidized starch modified with an oxidizing agent such as sodium hypochlorite, hydrogen peroxide, and arachis liquid, urea phosphorylated starch, maleic acid esterified starch, and succinic acid esterified starch. Acid esterified starches such as, and particularly urea phosphate starches can be preferably used, and these anionic starches can be used alone or in combination of two or more kinds.

The degree of modification of the cationic starch preferably has a degree of substitution of 0.02 to 0.07.

When the degree of substitution of the cationic starch is less than 0.02, it is difficult to form a starch polyion complex,
On the other hand, if the degree of substitution exceeds 0.07, the effect corresponding to the degree of modification of starch cannot be obtained, resulting in poor economic efficiency.

As for the degree of modification of the anionic starch, when the anionic starch is urea phosphorylated starch, it is preferable that the amount of bound phosphorus is 0.1 to 1.0% by weight, and that of other anionic starches. In this case, the substitution degree is 0.01 to 0.05
Those having are preferred.

When the degree of substitution of the anionic starch is 0.01 or the bound phosphorus content is less than 0.1% by weight, it becomes difficult to form a starch polyion complex, and conversely, the degree of substitution of 0.
05 or more than 1.0% by weight of bound phosphorus,
It is not preferable because the formed polyion complex has a stronger aggregation property.

An aqueous suspension of a zwitterionic starch in which a cationic starch and an anionic starch are mixed improves the dispersibility of the zwitterionic starch polyion complex after gelatinization. Is adjusted to 3-6, preferably 4-5 with an inorganic acid such as hydrochloric acid, sulfuric acid and nitric acid or an organic acid such as acetic acid.

When the zwitterionic starch is produced, the starch produced by adjusting the pH of the aqueous suspension to 3-6, preferably 4-5 may be used as the aqueous suspension. it can.

When the pH of the aqueous suspension is less than 3, it is not preferable because the molecule is cleaved by acid hydrolysis by heat during gelatinization.

On the other hand, if the pH exceeds 6, the amphoteric starch polyion complex will have a strong aggregation property, which is not preferable.

At the time of addition, a zwitterionic starch polyion complex is formed at the same time as gelatinization by a continuous gelatinizer and used.

In the method of the present invention, the zwitterionic starch polyion complex is added to the pulp slurry in a gelatinized form, but the gelatinization of the starch is preferably performed by a continuous gelatinizer.

Suitable gelatinizers for use in the present invention are:
Any gelatinization device of the type that instantly gelatinizes starch by injecting steam holding a pressure of ³ to 10 kg / cm ² into an aqueous suspension of starch, such as generally oxidized starch,
A continuous gelatinizer used for gelatinizing a cationic starch or the like, or a continuous gelatinizer for thermochemical modification in which raw starch is gelatinized and simultaneously reduced in viscosity by an oxidizing agent can be preferably used.

However, in order to uniformly disperse the produced starch polyion complex, a gelatinizing device of a type that exerts a hydrodynamic force at the time of steam blowing must be used.
Therefore, it is not preferable to use a batch type gelatinizer because a uniform zwitterionic starch polyion complex is not formed.

In addition, upon addition, it is necessary to gelatinize sufficiently so that ungelatinized starch does not remain.

In the present invention, the above-mentioned amphoteric starch polyion complex is added to a pulp slurry, and papermaking and drying are carried out by a conventional method.

The amount of the zwitterionic starch polyion complex added is preferably 1.0 to 10.0% by weight based on the dry weight of pulp of the raw material pulp slurry.

In the present invention, the zwitterionic starch polyion complex may be used in combination with commercially available chemicals such as van sulphate, sizing agents and wet strength agents, but there is no limitation on the use thereof. There is no.

Although the present inventors have not sufficiently clarified the effect of improving the internal strength by the paperboard manufacturing method of the present invention, the cationic starch and the anionic starch are ionically bound to each other, and they are apparently macromolecules. It is considered that the resulting amphoteric starch polyion complex is fixed to the fibers and reinforces the hydrogen bond between the fibers to improve the internal strength.

These mechanisms are the same as those of conventional modified starch typified by cationic starch or synthetic polymers such as PAM, but by having both cation and anion ions in a good balance, the ionic balance of the paper stock is improved. It is considered that the largest and most important factor for improving the internal strength is that a larger amount of starch than conventional starch or PAM can be fixed in the paper because the amount of starch added can be increased without breaking.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these.

[0049]

Embodiment 1

Waste paper pulp for general cores, which was obtained by disintegrating corrugated cardboard waste paper, was adjusted to a pulp slurry having a concentration of 2.0% by weight.

Then, after a commercially available liquid sulphate sulphate as a sulphate sulphate was adjusted to a concentration of 3.0% by weight in the pulp slurry, the solid content was 1.5% with respect to the dry weight of the pulp.
% Added.

Further, as shown in Table 1, cationic starch and anionic starch were mixed, and the powder mixture was suspended in water to give an aqueous suspension of zwitterionic starch, which was then adjusted to pH 5. with acetic acid. 0, and using a CEPI-4JET type gelatinizer (manufactured by Nippon Shokuhin Kako Co., Ltd.), the concentration of the aqueous suspension was 8.0% by weight, the gelatinization temperature was 130 ° C, and the finished concentration was 1.
By gelatinizing under the condition of 0% by weight, each of the amphoteric starch polyion complexes 1 to 21 used in this example was obtained.

[0053]

[Table 1]

The cationic starch in Table 1 is corn starch cationized with a cationizing agent in an aqueous suspension.

At this time, as the cationizing agent, diethylaminoethyl chloride hydrochloride was used as the tertiary amine, and 3-chloro-2-hydroxypropyltrimethylammonium chloride was used as the quaternary ammonium salt.

On the other hand, UPS used as anionic starch
-1 and UPS-2 are both cornstarch phosphorylated with urea, and the bound phosphorus content of UPS-1 is 0.45.
% By weight, and the bound phosphorus content of UPS-2 is 0.65% by weight.

Anion-1 and anion-2 are
Both are maleic esterified starches based on corn starch, anion-1 having a degree of substitution of 0.02 and anion-2 having a degree of substitution of 0.04.

Then, each amphoteric starch polyion complex 1 was added to the pulp slurry to which the vanadium sulfate was added.
2.0 to 2.0% by weight based on the dry weight of pulp,
The final furnishes 1A to 21A were obtained by finally adjusting the concentration with water to a pulp concentration of 1.0% by weight.

Similarly, each amphoteric starch polyion complex 1 was added to a pulp slurry to which vansulfate was added.
~ 21 added to the pulp dry weight of 4.0% by weight,
The furnishes 1B to 21B were obtained by finally adjusting the concentration with water to a pulp concentration of 1.0% by weight.

Similarly, each amphoteric starch polyion complex 1 was added to a pulp slurry to which vansulfate was added.
~ 21 is added to the pulp dry weight by 6.0% by weight,
By finally adjusting the concentration with water to a pulp concentration of 1.0% by weight, furnishes 1C to 21C were obtained.

Furthermore, to the pulp slurry to which the vanadium sulfate was added, the zwitterionic starch polyion complexes 3 and 1 were added.
8.0 and 10% by weight based on the dry weight of pulp, respectively, and finally the concentration was adjusted with water to a pulp concentration of 1.0% by weight to obtain furnishes 3D and 11D. .

Similarly, amphoteric starch polyion complexes 3 and 11 were added to a pulp slurry to which van sulphate was added, respectively, by 10.0% by weight based on the dry weight of pulp, and finally the pulp concentration was adjusted with water. The furnishes 3E and 11E were obtained by adjusting the concentration to 1.0% by weight.

The furnishes 1A to 21A, the furnishes 1B to 21B, the furnishes 1C to 21C, and the furnishes 3D obtained above.
And 11D, and the furnishes 3E and 11E, using a square sheet machine (manufactured by Kumagai Riki Kogyo Co., Ltd.), the target basis weight is 160 g /
Paper was made under the conditions of m ² and a papermaking temperature of 30 ° C.

An automatic sheet press (Kumagaya Riki Kogyo)
1st press 3.5kg / cm ² for 2 minutes, 2nd press 3.5kg / cm ² for 1 minute to dehydrate, and further tumble dryer (Kumagaya Riki Kogyo Co., Ltd.) Product), and dried at 103 ° C for 2 minutes, then at 20 ° C, 65% RH
By adjusting the humidity all day and night under the conditions of
A, paperboard 1B-21B, paperboard 1C-21C, paperboard 3D and 11D, paperboard 3E and 11E were manufactured, respectively.

[0065]

Example 2

Waste paper pulp for a reinforced core obtained by disintegrating corrugated cardboard waste paper was adjusted to a pulp slurry having a concentration of 2.0% by weight.

To the pulp slurry, 1.5% by weight of liquid van sulphate commercially available as vanadium sulphate was added, after which the concentration was adjusted to 4.5% by weight.

Further, as shown in Table 2, a cationic starch and an anionic starch were mixed, and the powder mixture was suspended in water to obtain an aqueous suspension of zwitterionic starch.
After adjusting to 5.0, as in Example 1, CEPI-
Using a 4JET type gelatinizer (manufactured by Nippon Shokuhin Kako Co., Ltd.), the aqueous suspension concentration was 8.0% by weight, the gelatinization temperature was 130 ° C,
The amphoteric starch polyion complexes 22 to 30 used in this example were obtained by gelatinizing under a finished concentration of 1.0% by weight.

[0069]

[Table 2]

The cationic starch in Table 2 is zwitterionic starch polyion complex 22 to 24, which is corn starch cationized with a cationizing agent in an aqueous suspension, and zwitterionic starch polyion complex 25. For -30, tapioca starch is cationized with a cationizing agent in an aqueous suspension.

Specifically, the cationic starch for the zwitterionic starch polyion complex 22-24 is:
Cation-1, the cationic starch for the zwitterionic starch polyion complex 25-27 is Cation-2, and the cationic starch for the zwitterionic starch polyion complex 28-30 is Cation-
It is 3.

At this time, as the cationizing agent, diethylaminoethyl chloride hydrochloride was used as the tertiary amine, and 3-chloro-2-hydroxypropyltrimethylammonium chloride was used as the quaternary ammonium salt.

On the other hand, UPS used as anionic starch
-1, and UPS-2, as described in Example 1,
Both are cornstarch phosphorylated with urea.
The bound phosphorus content of S-1 was 0.45% by weight, and UPS-
The bound phosphorus content of 2 is 0.65% by weight.

Then, 2.0 wt% of each zwitterionic starch polyion complex was added to the pulp slurry to which the vanadium sulfate was added, and the final pulp concentration was 1.0 with water. The furnish 22A to 30A was obtained by adjusting the concentration so that the weight of the furnish was 22% to 30A.

Similarly, 4.0 wt% of each zwitterionic starch polyion complex was added to the pulp slurry to which van sulphate had been added, based on the dry weight of pulp, and finally a pulp concentration of 1. By adjusting the concentration to be 0% by weight, the furnishes 22B to 30B were obtained.

Similarly, 6.0 wt% of each zwitterionic starch polyion complex was added to the pulp slurry to which van sulphate was added, based on the dry weight of pulp, and finally the pulp concentration was adjusted to 1. By adjusting the concentration to 0% by weight, the furnishes 22C to 30C were obtained.

The furnishes 22A to 30A, the furnishes 22B to 30B, and the furnishes 22C to 30C obtained as described above are the same as in Example 1, and are rectangular sheet machines (Kumagaya Riki Kogyo Co., Ltd.).
Manufactured), target basis weight 210 g / m ² , papermaking temperature 30
Paper was made under the condition of ° C.

Then, an automatic sheet press (Kumagaya Riki Kogyo)
1st press 3.5kg / cm ² for 2 minutes, 2nd press 3.5kg / cm ² for 1 minute to dehydrate, and further tumble dryer (Kumagaya Riki Kogyo Co., Ltd.) Product), and dried at 103 ° C for 2 minutes, then at 20 ° C, 65% RH
By adjusting the humidity all day and night under the conditions of
0A, paperboards 22B to 30B, and paperboards 22C to 30C were manufactured.

[0079]

[Comparative example]

Using the pulp slurry containing the sulphate of vanadium before the addition of the zwitterionic starch polyion complex used in Example 1 above as a stock material, the same procedure as in Example 1 above was used to carry out a control paper. 1 (blank) was manufactured.

Further, the pulp slurry used in Example 2 above, to which the vanadium sulfate was added before the addition of the zwitterionic starch polyion complex was used as a stock material.
Control paper 2 (blank) was manufactured by the same process as in Example 2 above.

Further, as a PAM type paper strength enhancer, DS32 is used.
1 (trade name, manufactured by Japan PMC Co., Ltd.) was added to the pulp slurry containing van sulphate used in Example 2 in an amount of 0.4% by weight, and a control paper 31 was obtained by the same process as in Example 2. Manufactured.

Similarly, 0.8% by weight of DS321 was added to the pulp slurry containing van sulphate used in Example 2 and the control paper 32 was produced by the same process as in Example 2.

Similarly, 1.2% by weight of DS321 was added to the pulp slurry to which the vanadium sulfate soil used in Example 2 was added, and the control paper 33 was manufactured by the same process as in Example 2.

In addition to the above, for comparison, cation-1, cation-2, and UPS-2 used in Example 2 were individually added to the pulp slurry to which bansulfate used in Example 2 was added. 2.0 wt% was added, and the control paper 41, the control paper 51, and the control paper 61 were manufactured by the same steps as in Example 2.

Similarly, 4.0% by weight of each starch was individually added to the pulp slurry containing van sulphate used in Example 2 and the same procedure as in Example 2 was repeated to prepare Control Paper 4
2. Control paper 52 and control paper 62 were manufactured.

Similarly, 6.0% by weight of each starch was individually added to the pulp slurry containing bansulfate used in Example 2 and the same procedure as in Example 2 was repeated to prepare Control Paper 4
3, the control paper 53, and the control paper 63 were manufactured, respectively.

That is, the control papers 41 to 4 were prepared by using cation-1.
3 with cation-2, control papers 51-53, UPS-
The control papers 61 to 63 were manufactured in accordance with 2.

[0089]

[Test example]

Paperboards 1A to 21A (addition amount: 2.0% by weight), paperboards 1B to 21B (addition amount: 4.0% by weight), and paperboard 1C to 21C (addition amount: 6) obtained in Example 1 above. ．
0% by weight), paperboard 3D and 11D (addition amount of 8.0% by weight), paperboard 3E and 11E (addition amount of 10.0% by weight), and the control paper 1 obtained in the above comparative example. Then, the freeness and basis weight were measured, and the specific compression and the specific burst were tested.

Paperboards 22A-30A obtained in Example 2 above
(Additional amount of 2.0% by weight), paperboard 22B-30B
(Additional amount of 4.0% by weight), paperboard 22C to 30C
(With an addition amount of 6.0% by weight), and the control paper 2, the control papers 31 to 33, the control papers 41 to 43, the control papers 51 to 53, and the control papers 61 to 63 obtained in the above comparative examples, Water degree,
In addition to measuring the basis weight, specific compression, breaking length, and elongation were tested.

Here, each item was measured or tested by the following method.

The basis weight was measured by a method according to JIS P8124. The specific compression was tested by the method according to JIS P8126. Specific rupture is JIS P 8
Tested according to the method of 112. The breaking length is JIS
It tested by the method according to P8113. The growth is
It was tested by a method according to JIS P 8132.

The above results are shown in Tables 3 to 6.

[0095]

[Table 3]

[0096]

[Table 4]

[0097]

[Table 5]

[0098]

[Table 6]

[0099]

【The invention's effect】

In the paperboard manufacturing method of the present invention, the amphoteric starch polyion complex is added to manufacture the paperboard. Therefore, the manufactured paperboard is excellent in disintegrating property and laminating property.
Moreover, it is possible to economically manufacture a paperboard having an improved internal strength of the paper without impairing the operability of a machine used for manufacturing a paper machine or the like.

Claims (8)

[Claims] 1. A method for producing paperboard, which comprises adding a zwitterionic starch polyion complex to a pulp slurry to make a paper. 2. A method for producing paperboard, which comprises adding a zwitterionic starch polyion complex comprising a mixture of a cationic starch and an anionic starch to a pulp slurry for papermaking. 3. Paper making by adding a zwitterionic starch polyion complex consisting of a mixture of 80 to 20% by weight of cationic starch and 20 to 80% by weight of anionic starch to a pulp slurry. , Paperboard manufacturing method. 4. A cationic starch cationized with at least one cationizing agent selected from diethylaminoethyl chloride, 3-chloro-2-hydroxypropyltrimethylammonium chloride and 2,3-epoxypropyltrimethylammonium chloride. And the anionic starch is anionized by at least one means selected from oxidation, urea phosphorylation, maleic acid esterification and succinic acid esterification. Method. 5. The degree of substitution of the cationic starch is 0.02 to 0.02.
The method for producing paperboard according to claim 3, wherein the anionic starch has a content of 0.07 and the anionic starch is a urea phosphorylated starch having a bound phosphorus content of 0.1 to 1.0% by weight. 6. The degree of substitution of the cationic starch is 0.02 to 0.02.
The paperboard manufacturing method according to claim 3, wherein the anionic starch has a substitution degree of 0.01 to 0.05. 7. A zwitterionic starch polyion complex is formed by gelatinizing an aqueous suspension of zwitterionic starch having a pH adjusted to 3 to 6 with a continuous gelatinizer to form a zwitterionic starch polyion complex. Is added to pulp slurry to make paper, a method for producing paperboard. 8. A zwitterionic starch polyion complex is added to a pulp slurry in an amount of 1.
A method for producing paperboard, which comprises adding 0 to 10.0% by weight to make a paper.