JP2015014070A - Ruled line crack inhibitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ruled line crack inhibitor which can impart excellent ruled line crack prevention suitability to a paperboard by external addition.SOLUTION: A ruled line crack inhibitor consists of an amide amine compound or its salt obtained by reacting 1 mol of a polyamine compound of formula (1) with 2-4 mol of a 10-14C fatty acid and has a carbon number (A) of fatty acids per amino group of formula (2) of 5.5-8.5. Formula (1) NH-(CHCH-NH)H, where x is an integer of 3-5. Formula (2) A=carbon number of fatty acid×amidation rate, where amidation rate=(amine value at the reaction start-amine value at the reaction end)/amine value at the reaction start.

Description

  The present invention relates to a ruled line cracking inhibitor that can efficiently impart excellent ruled line cracking prevention properties to paperboard by external addition.

  Paperboard is a general term for thick paper, and it includes so-called corrugated cardboard and white paperboard, and is often used as a packaging material. A problem with these paperboards is ruled line cracking. Ruled line cracking refers to a phenomenon in which a front sheet of cardboard is cracked along a ruled line when the box is assembled or when the assembled box is exposed to dry conditions. This causes not only appearance problems but also problems such as a decrease in box strength.

  In general, the addition of a drug is taken as a technique for solving the problems related to paper, and there are two types of addition methods, internal addition and external addition. The merit of external addition is that the amount of use can be reduced as compared with the addition inside. In addition, there is a problem in that the effect of the drug is difficult to be exhibited when the amount of used paper increases in the internal addition.

As countermeasures against ruled line cracking, Patent Document 1 discloses a method for preventing ruled line cracking by adding a cationic surfactant, and Patent Document 2 discloses a method for preventing ruled line cracking by adding an amphoteric surfactant. ing.
However, in the methods of Patent Documents 1 and 2, the effect of preventing ruled line cracking is inferior unless the addition amount is increased in the external addition. Therefore, there has been a demand for the development of a ruled line cracking preventing agent that can efficiently impart excellent ruled line cracking prevention properties to paperboard by external addition.

JP-A-11-200209 Japanese Patent Laid-Open No. 2001-262496

  The present invention has been made based on the circumstances as described above, and an object thereof is to provide a ruled line cracking preventing agent capable of efficiently imparting excellent ruled line cracking preventing property to paperboard by external addition. It is.

  The present inventors have found that an amidoamine compound or a salt thereof obtained by reacting a specific polyamine compound and a specific fatty acid in a predetermined ratio can achieve the above object.

That is, the ruled line crack preventing agent of the present invention is an amidoamine compound or a salt thereof obtained by reacting 2 to 4 mol of a fatty acid having 10 to 14 carbon atoms to 1 mol of the polyamine compound represented by the formula (1). Hereinafter, the number of carbon atoms (A) of the fatty acid per amino group represented by the formula (2) is 5.5 to 8.5. Is.
_{NH 2 - (CH 2 CH 2} -NH) x H ··· Equation (1)
(In the formula, x is an integer of 3 to 5.)
A = fatty acid carbon number × amidation rate formula (2)
Amidation rate = (amine value at the start of reaction−amine value at the end of reaction) / amine value at the start of reaction

In general, the paperboard can be made flexible by steric hindrance due to the long alkyl chain length of the fatty acid in the amidoamine compound or the large number of reaction moles of the fatty acid with respect to the polyamine compound. Can be reduced, and cracking of the ruled line can be made difficult to occur. On the other hand, in order to make it easy to exert the ruled line cracking effect by external addition, a method of increasing the drug permeability is adopted.
However, in order to increase the permeability in the amidoamine compound, it is necessary to shorten the alkyl chain length of the fatty acid or to reduce the number of moles of reaction of the fatty acid, which is contrary to flexibility.
Therefore, in the present invention, in order to impart a good balance between flexibility and permeability, an amidoamine compound (salt) obtained by reacting a specific polyamine compound and a specific fatty acid at a predetermined ratio is used as a ruled line cracking inhibitor. It is characterized by that.

  The ruled line cracking preventive agent of the present invention comprises an amidoamine compound (salt) capable of imparting flexibility, and penetrates when the number of carbon atoms (A) of fatty acid per unit amino group is defined within a predetermined range. It is also possible to impart good balance. Therefore, the ruled line cracking prevention ability excellent in the paperboard can be efficiently provided by external addition.

  Hereinafter, each component for producing the amidoamine compound (salt) used as the ruled line cracking preventing agent of the present invention will be described.

[Polyamine compound]
The polyamine compound used in the present invention is a linear polyethylene polyamine represented by the formula (1). In the formula, x is an integer of 3 to 5, and tetraethylenepentamine in which x is 4 is particularly preferable. If x is too small, the number of moles of the reaction of the fatty acid is reduced, and sufficient flexibility may not be obtained.
In addition, the mixture which consists of 2 or more types of polyamine compounds from which x differs in a formula can also be used.

〔fatty acid〕
The fatty acid used in the present invention is a fatty acid having 10 to 14 carbon atoms. Specific examples include capric acid, lauric acid, and myristic acid, which are linear saturated fatty acids having 10 to 14 carbon atoms. Of these, myristic acid having 14 carbon atoms is preferred. One kind selected from these fatty acids may be used alone or in a mixture of two or more kinds. In addition, when using as a mixture, the numerical value computed by the weighted average from the carbon number of each fatty acid is made into the fatty acid carbon number in Formula (2).
If the number of carbon atoms of the fatty acid is less than 10, sufficient flexibility may not be obtained, and if it is greater than 14, sufficient permeability may not be obtained.

[Amidamine compound]
The amidoamine compound used in the present invention is obtained by subjecting 2 mol to 4 mol of the fatty acid to a condensation reaction with respect to 1 mol of the polyamine compound. Hereinafter, the number of moles of fatty acid to be reacted with 1 mole of the polyamine compound is also referred to as “reaction molar ratio”.
If the reaction molar ratio is less than 2, sufficient flexibility may not be obtained, and if it is greater than 4, sufficient permeability may not be obtained.

In the present invention, in order to adjust the balance between the number of amino groups of the polyamine compound and the number of carbon atoms of the fatty acid, the number of carbon atoms (A) of the fatty acid per amino group is defined. Thus, by adjusting the balance between the number of amino groups of the polyamine compound and the number of carbon atoms of the fatty acid within a predetermined range, flexibility and permeability can be imparted to the paperboard in a well-balanced manner, and it is possible to prevent cracking of the paperboard. it can.
Specifically, the carbon number (A) of the fatty acid per amino group represented by the formula (2) is adjusted to a range of 5.5 to 8.5.
A = fatty acid carbon number × amidation rate formula (2)
Amidation rate = (amine value at the start of the reaction−amine value at the end of the reaction) / amine value at the start of the reaction The number of fatty acid carbon atoms in the formula (2) is the number of fatty acids in the case of using one kind of fatty acid. It is the number of carbons and is a numerical value calculated by weighted average from the number of carbons of each fatty acid when a mixture of two or more fatty acids is used. Further, the amine value at the start of the reaction and the amine value at the end of the reaction can be measured by dissolving each sample in, for example, acetic acid and using a potentiometric titrator.

  The amidoamine compound used in the present invention is a mixture of the polyamine compound and the fatty acid without a solvent, and the temperature is increased to, for example, 160 to 230 ° C. while expanding the sales in an inert gas atmosphere such as nitrogen gas. It can manufacture by making it react, removing produced | generated water out of a reaction system.

[Rule line cracking inhibitor]
The ruled line crack preventing agent of the present invention comprises the above amidoamine compound (salt), and comprises one or more compounds selected from the above amidoamine compounds (salts). The ruled line crack preventing agent of the present invention can typically be used as a dispersion by dispersing the above-mentioned amidoamine compound (salt) in a dispersion medium. Note that water is preferable as the dispersion medium.

When the ruled line cracking inhibitor of the present invention is used as a dispersion, it is preferable to neutralize the amidoamine compound with an acid to make a salt in order to facilitate the preparation of the dispersion. Examples of the acid used in this case include various inorganic acids or organic acids. Specifically, hydrochloric acid, sulfuric acid, carbonic acid, nitric acid, phosphoric acid, formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, Examples include gluconic acid, salicylic acid, hydroxyvaleric acid, aspartic acid, glutamic acid, taurine, sulfamic acid, and the like. Preferred are formic acid, acetic acid, glycolic acid, lactic acid and gluconic acid.
When using an acid to prepare a salt of an amidoamine compound, the amine value of the obtained amidoamine compound is measured, and the mass of the acid having an acid value equivalent to the measured amine value is calculated. It is preferable to mix the acid and the amidoamine compound.

  When the ruled line cracking inhibitor of the present invention is used as a dispersion, the content of the amidoamine compound (salt) contained in the dispersion is appropriately adjusted depending on the type of paperboard and the coating conditions. 20% by mass, preferably 0.1 to 5% by mass.

[Addition to paper]
Although the ruled line cracking preventive agent of the present invention can be used not only externally but also internally, from the point that the amount used can be reduced or the effect can be expressed even for paperboard with a large amount of used paper. It is preferable to use an external addition performed on paper once made.
When the ruled line cracking preventive agent of the present invention is used by external addition, the coating amount on the paperboard surface is preferably in the range of 0.005 to 1 g / m ^{2 in} terms of amidoamine compound (salt), and particularly preferably 0.8. A range of 01 to 0.5 g / m ² is preferred.
The ruled line cracking preventing agent of the present invention may be used alone as a drug on paper, or may be used in combination with other drugs such as a sizing agent.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

(Preparation of ruled line cracking inhibitor)
The polyamine compounds and fatty acids listed in Table 1 were subjected to a condensation reaction at the reaction molar ratios listed in Table 1 (Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 6) to obtain amidoamine compounds. In this reaction, the amidation rate of the obtained amidoamine compound was calculated based on the following formula by measuring the amine value immediately after mixing the polyamine compound and the fatty acid and the amine value after the completion of the reaction.
Amidation rate = (amine value at the start of reaction−amine value at the end of reaction) / amine value at the start of reaction The amine value is obtained by dissolving 0.05 to 0.2 g of a sample in 80 mL of acetic acid and performing potentiometric titration. It measured using apparatus COM-1700 (made by Hiranuma Sangyo Co., Ltd.).

  An amount of acetic acid equivalent to the amine value of this amidoamine compound was added to ion-exchanged water, and this aqueous acetic acid solution was added to the reaction solution to obtain a dispersion containing an amidoamine compound acetate. This dispersion was used as a ruled line cracking inhibitor and subjected to a permeability test and an external additive chemical solution test. The content of the amidoamine compound acetate in the dispersion was 10% by mass for the permeability test and 0.2% by mass for the external additive chemical test.

[Evaluation of ruled line cracking inhibitor]
Using the above-obtained dispersions of ruled line cracking inhibitors (Examples 1 to 5, Comparative Examples 2 to 7), handsheets were made as follows. In Comparative Example 1, it was immersed in ion-exchanged water instead of the dispersion of the ruled line cracking inhibitor.
The obtained handsheet was evaluated for flexibility and ruled line cracking as an external additive chemical test. Moreover, the permeability with respect to the ready-made corrugated cardboard paper was evaluated using the obtained dispersion liquid.

(1) Papermaking of handsheets Handsheets were made according to the following procedure with reference to the method of preparing JIS P8222 handsheets for testing. A pulp slurry containing 1% by mass of NSBKP (conifer bleached pulp) was prepared. 130 g of this pulp slurry was taken in a beaker, paper-made with a TAPPI standard sheet machine (manufactured by Yasuda Seiki Seisakusho), pressed with a hydraulic press machine (manufactured by Yasuda Seiki Seisakusho) for 5 minutes, and then drum A hand dryer sheet having a basis weight of 60 g / m ² was made by drying at 105 ° C. for 2.5 minutes using a type dryer (manufactured by Yasuda Seiki Seisakusho).

The handmade sheet made of paper was immersed in the above dispersion to externally add the chemical solution, and dried again with a drum dryer. Under the present circumstances, the external addition coating amount was 0.10 g / m < ² > in conversion of the amide amine compound acetate. The handsheet was conditioned for 17 hours in a constant temperature and humidity chamber (temperature 23 ° C., humidity 50%). Three handsheets were made for each dispersion.

A handsheet having a basis weight of 300 g / m ² was similarly made. 630 g of the initial pulp slurry was taken, and a handsheet was made in the same process as above. At this time, drying with a drum dryer was performed for 2.5 minutes × 3 times, and after external addition, drying was performed twice.

(2) Evaluation of flexibility The bending stiffness of the handsheet having a humidity basis weight of 60 g / m ² was measured with a pure bending tester (manufactured by Kato Tech Co., Ltd .: KES-FB2). Each example was measured 6 times, and the average value of bending stiffness was obtained and summarized in Table 2.

Furthermore, the flexibility was evaluated according to the following criteria, and the evaluation was also summarized in Table 2. As the evaluation criteria, a sample in which a decrease in bending stiffness was found to be less than 90% with respect to the value of bending stiffness in Comparative Example 1 immersed in only ion-exchanged water, that is, a sample with improved flexibility was regarded as acceptable.
(Evaluation criteria)
Flexural rigidity is less than 7.5 × 10 ⁻⁵ N · m ² / m: Good flexibility (◯)
Flexural rigidity is 7.5 × 10 ⁻⁵ N · m ² / m or more: Insufficient flexibility (×)

(3) Evaluation of permeability With reference to JIS R3257, a 10% by mass dispersion is dropped onto a pre-made corrugated cardboard (liner / core / liner three-layer structure) to which sizing is applied, and then the wafer is washed. -The contact angle immediately after dripping was measured with the process evaluation apparatus (Kyowa Interface Science Co., Ltd. product: CA-S150 type | mold). In each case, the measurement was performed three times, and the average value of the contact angles was determined and listed in Table 2.

Furthermore, the permeability was evaluated according to the following criteria, and the evaluation was also summarized in Table 2.
(Evaluation criteria)
The average value of the contact angle is less than 80 °: good permeability (◯)
The average value of the contact angle is less than 80 °: the permeability is insufficient (×)

(4) Evaluation of ruled line cracking Evaluation of ruled line cracking was performed according to the following procedure. The handsheet having a basis weight of 300 g / m ² that had been conditioned was dried at 105 ° C. for 3 hours in a dryer. The dried sheet was folded in half, and an unheated drum dryer was set to a closed type and allowed to pass for 1.5 minutes. The passed half-moon handsheet was opened horizontally, bent again in the same direction, the crack length of this folded part was measured, and the ruled line crack length ratio was obtained from the following formula 3. Each example was measured twice, and the average value of the ruled line crack length ratio was determined.
Using a sheet immersed in ion-exchanged water instead of the dispersion as a blank, the improvement rate with respect to the ruled line crack length ratio (41%) of this sheet was determined according to the following formula 4 and listed in Table 2.
Ruled line crack length ratio (%) = [length of ruled line crack (mm) / total length of sheet (mm)] × 100 Formula (3)
Ruled line crack improvement rate (%) = [1-ruled line crack length ratio (%) / blank ruled line crack length ratio (41%)] × 100 Formula (4)

Furthermore, the ruled line crack improvement rate was evaluated according to the following criteria, and the evaluations are also summarized in Table 2.
(Evaluation criteria)
Ruled line crack improvement rate is 50 or more: The ruled line crack improvement effect is good (○)
Ruled line crack improvement rate is less than 50: Ruled line crack improvement effect is insufficient (×)

In Examples 1 to 5 using the ruled line crack preventing agent of the present invention, the bending stiffness was less than 7.5 × 10 ⁻⁵ N · m ² / m and the contact angle was less than 80 °. The crease line cracking improvement rate was 50% or more, and an excellent crease line cracking prevention effect was recognized.

  On the other hand, in Comparative Examples 2 to 6, in which the number of carbon atoms (A) of the fatty acid per amino group is higher than 8.5, since the flexibility is high but the permeability is low, the effect of preventing ruled line cracking is insufficient. . Further, in Comparative Example 7 in which the number of carbon atoms (A) of fatty acid per amino group is lower than 5.5, the permeability was sufficient, but since the flexibility was low, the effect of preventing ruled line cracking was insufficient. there were.

Claims (1)

It consists of an amidoamine compound or a salt thereof obtained by reacting 2 to 4 mol of a fatty acid having 10 to 14 carbon atoms with 1 mol of a polyamine compound represented by formula (1), and is represented by formula (2) A ruled line cracking inhibitor, wherein the number of carbon atoms (A) of the fatty acid per group is 5.5 to 8.5.
_{NH 2 - (CH 2 CH 2} -NH) x H ··· Equation (1)
(In the formula, x is an integer of 3 to 5.)
A = fatty acid carbon number × amidation rate formula (2)
Amidation rate = (amine value at the start of reaction−amine value at the end of reaction) / amine value at the start of reaction