JP4715590B2 - Softener for paper - Google Patents

Description

  The present invention relates to a softening agent for paper. More specifically, the present invention relates to a paper softener that can impart excellent flexibility and moisture retention to paper without reducing paper strength.

  Sanitary papers such as tissue paper and toilet paper are required to be softer and have a moisturizing feeling because they touch the skin directly during use.

  As a paper having a moisturizing feeling and flexibility, Patent Document 1 contains 1.0 to 300% by weight of at least one of a hygroscopic salt, a polyhydric alcohol, and a saccharide with respect to the fiber web. Patent Document 2 describes a tissue paper in which 0.01 to 5% of a water-soluble polyhydroxy compound is applied to the surface based on the dry fiber weight of the tissue paper. However, the paper (tissue paper) obtained using these compounds has insufficient flexibility.

  In Patent Document 3, at least one of an aliphatic alkyl group having 8 to 24 carbon atoms, an alkenyl group, or an acyl group, an amine salt, or an amine, and 3 to 15 carbon atoms is included. A flexible tissue paper containing 0.1 to 10% by weight of a polyhydric alcohol or a polyoxyalkylene adduct of a polyhydric alcohol per dry fiber is described. Patent Document 4 discloses a quaternized esteramine compound and a polyhydroxyl A paper product containing 0.005 to 5% by weight of a mixture with a compound is described, and Patent Document 5 consists of a dilong chain alkyl type quaternary ammonium salt, glycerin, and water or an alcohol having 4 or less carbon atoms. A paper softener composition is described. However, paper strength obtained using these compounds is reduced in paper strength.

Thus, a paper softening agent that satisfies all of the suppression of reduction in paper strength, improvement in flexibility, and improvement in moisture retention has not been obtained.
JP-A-5-156596 Japanese National Patent Publication No. 11-500496 Japanese Patent Laid-Open No. 7-109693 Japanese National Patent Publication No. 8-505663 Japanese Patent Laid-Open No. 4-100995

  The objective of this invention is providing the softener for paper which can provide the softness | flexibility and moisture retention which were excellent in paper, without reducing paper strength.

  As a result of intensive studies to solve the above problems, the present inventors can achieve the above object by combining the divalent to hexavalent polyhydric alcohol (a) and the specific compound (b) at a specific ratio. It has been found that a paper softener can be obtained.

  The paper softener of the present invention is a paper softener comprising a divalent to hexavalent polyhydric alcohol (a) and a compound (b), comprising the polyhydric alcohol (a) and the compound (b). The mass ratio is 95/5 to 99.5 / 0.5, and the compound (b) has the following general formula (1):

(A is a residue of a dicarboxylic acid having 4 to 12 carbon atoms, R ¹ , R ² , R ⁵ , and R ⁶ are each an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ Are each an alkylene group having 2 to 4 carbon atoms).

  The paper softener of the present invention is also a paper softener comprising a divalent to hexavalent polyhydric alcohol (a), a compound (b), and a quaternary ammonium compound (c), the polyhydric alcohol. The mass ratio between (a) and the compound (b) is 95/5 to 99.5 / 0.5, and the mass between the polyhydric alcohol (a) and the quaternary ammonium compound (c). The ratio is 95/5 to 99.5 / 0.5, and the compound (b) has the following general formula (1):

(A is a residue of a dicarboxylic acid having 4 to 12 carbon atoms, R ¹ , R ² , R ⁵ , and R ⁶ are each an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ Are each an alkylene group having 2 to 4 carbon atoms).

  The paper softener of the present invention can impart excellent softness and moisture retention to paper without reducing paper strength. Therefore, by using this softening agent, it is possible to obtain paper that maintains paper strength and has excellent flexibility and moisture retention.

  The paper softener of the present invention comprises a divalent to hexavalent polyhydric alcohol (a) (hereinafter sometimes referred to as “a” component) and a compound (b) (hereinafter sometimes referred to as “b” component). Alternatively, the paper softener of the present invention is based on the above divalent to hexavalent polyhydric alcohol (a), the above compound (b), and a quaternary ammonium compound (c) (hereinafter sometimes referred to as “c component”). Become. Hereinafter, each component, a paper softener, and a paper manufacturing method using the same will be described.

(2- to 6-valent polyhydric alcohol (a): component a)
Examples of the divalent to hexavalent polyhydric alcohol include propylene glycol, dipropylene glycol, butylene glycol, glycerin, diglycerin, sorbitol, xylitol, and polyethylene glycol. These divalent to hexavalent polyhydric alcohols (a) may be used alone or in combination of two or more.

(Compound (b): component b)
Compound (b) has the following general formula (1):

(A is a residue of a dicarboxylic acid having 4 to 12 carbon atoms, R ¹ , R ² , R ⁵ , and R ⁶ are each an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ Are each an alkylene group having 2 to 4 carbon atoms.

  In the general formula (1), A is a residue of a dicarboxylic acid having 4 to 12 carbon atoms. Examples of such a dicarboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, Azelaic acid, sebacic acid, dodecanedioic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, and terephthalic acid. Of these, dicarboxylic acids having 6 to 10 carbon atoms are preferred. When the number of carbon atoms exceeds 12, the paper softener using such a compound imparts flexibility to the paper, but the resulting compound has a high melting point and may be difficult to handle.

In the general formula (1), R ¹ , R ² , R ⁵ , and R ⁶ having an alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and an isobutyl group. Etc. Among these, a methyl group and an ethyl group are preferable. When the number of carbon atoms exceeds 4, the softener for paper using such a compound imparts flexibility to the paper, but the resulting compound has a high melting point and may be difficult to handle.

In the general formula (1), examples of the alkylene group having 2 to 4 carbon atoms of R ³ and R ⁴ include an ethylene group, a propylene group, and a butylene group. Among these, a propylene group is preferable.

  The compound (b) is obtained by reacting a dialkylaminoalkyleneamine with the dicarboxylic acid. This reaction is performed by a normal condensation reaction. The compound (b) can be used as it is, but the handleability is improved by neutralization with an acid. As the acid used in this case, formic acid, acetic acid, glycolic acid, lactic acid, gluconic acid and the like are preferable in consideration of the case where the acid remains on the paper after papermaking. These acids are used in an equivalent amount based on the amine value of the compound (b).

(Quaternary ammonium compound (c): component c)
The quaternary ammonium compound is used for further imparting flexibility to the paper. Examples of the quaternary ammonium compound include alkyl-type quaternary ammonium compounds, ester-type quaternary ammonium compounds, amide-type quaternary ammonium compounds, imidazolinium-type quaternary ammonium compounds, and the like.

  The alkyl type quaternary ammonium compound has the following general formula (2):

(R ⁷ is an alkyl group or alkenyl group having 8 to 22 carbon atoms, R ⁸ and R ⁹ are each an alkyl group having 8 to 22 carbon atoms, an alkenyl group having 8 to 22 carbon atoms, or 1 carbon atom. to 3 alkyl group, a hydroxyalkyl group having 1 to 3 carbon atoms, a benzyl group, _{or, - (CH 2 CH 2 O} ) m H a (m is 1 to ^{10), R 10} is a carbon number 1 to 3 An alkyl group of 1 to 3, a hydroxyalkyl group having 1 to 3 carbon atoms, a benzyl group, or — (CH ₂ CH ₂ O) _n H (n is 1 to 10), and X ⁻ is an anion). Is done.

In the general formula (2), R ⁷ and R ⁸ are each preferably an alkyl group or alkenyl group having 12 to 22 carbon atoms, and R ⁹ is a methyl group or — (CH ₂ CH ₂ O) _m H (m Are preferably 1 to 10), and R ¹⁰ is preferably a methyl group or an ethyl group.

  The ester type quaternary ammonium compound has the following general formula (3):

(R ¹¹ CO is an acyl group having 10 to 24 carbon atoms, R ¹² and R ¹³ are each R ¹¹ COOR ¹⁵ , an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group having 1 to 3 carbon atoms, Or — (CH ₂ CH ₂ O) _p H (p is 1 to 10), and R ¹⁴ is an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group having 1 to 3 carbon atoms, a benzyl group, or — (CH ₂ CH ₂ O) _q H (q is 1 to 10), R ¹⁵ is an alkylene group having 2 to 4 carbon atoms, and X ⁻ is an anion).

In the general formula (3), R ¹¹ CO is preferably an acyl group having 12 to 22 carbon atoms, R ¹² and R ¹³ are preferably R ¹¹ COOR ¹⁵ or a hydroxyalkyl group having 2 or 3 carbon atoms, and R ¹⁴ Is preferably a methyl group or an ethyl group, and R ¹⁵ is preferably an alkylene group having 2 or 3 carbon atoms.

  The amide type quaternary ammonium compound has the following general formula (4):

(R ¹⁶ CO and COR ¹⁷ are each an acyl group having 10 to 24 carbon atoms, R ¹⁸ and R ¹⁹ are each an alkylene group having 1 to 3 carbon atoms, and R ²⁰ and R ²¹ are 1 carbon atoms. An alkyl group of ˜3, a hydroxyalkyl group of 1 to 3 carbon atoms, a benzyl group, or — (CH ₂ CH ₂ O) _r H (r is 1 to 10), and X ⁻ is an anion) It is represented by

In the general formula (4), R ¹⁶ CO and COR ¹⁷ are each preferably an acyl group derived from a carboxylic acid having 12 to 22 carbon atoms, R ¹⁸ and R ¹⁹ are preferably an ethylene group, and R ²⁰ is preferably a methyl group. R ²¹ is preferably a methyl group or — (CH ₂ CH ₂ O) _r H (r is 1 to 10).

  The imidazolinium type quaternary ammonium compound has the following general formula (5):

(R ²² is an alkyl group or alkenyl group having 8 to ²² carbon atoms, R ²³ is an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group having 1 to 3 carbon atoms, a benzyl group, or — (CH a _{2 CH 2 O) s H (} s is 1 to 10), ^{COR 24} is an acyl group having a carbon number of 10 to 24, and X ^- is represented by an anion).

In the general formula (5), R ²² is preferably an alkyl group or alkenyl group having 11 to 21 carbon atoms, and R ²³ is a methyl group or — (CH ₂ CH ₂ O) _s H (s is 1 to 10). COR ²⁴ is preferably an acyl group derived from a carboxylic acid having 12 to 22 carbon atoms.

  Among these quaternary ammonium compounds, the following general formula (6):

An ester-type quaternary ammonium compound represented by (R ²⁵ CO and R ²⁶ CO are each an acyl group having 12 to 22 carbon atoms, and X ⁻ is an anion) is more preferable.

In the general formula (6), R ²⁵ CO and R ²⁶ CO are each an acyl group derived from a carboxylic acid having 12 to 22 carbon atoms. Examples of such a carboxylic acid include lauric acid, Linderic acid, myristic Examples include acids, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, linoleic acid, linolenic acid, elaidic acid, arachidic acid, eicosenoic acid, behenic acid, erucic acid and the like. These carboxylic acids may be used alone or in combination of two or more.

In the above general formulas (2) to (6), X ⁻ is an anion, and examples thereof include fluorine ion, chlorine ion, bromine ion, iodine ion, methyl sulfate ion, and ethyl sulfate ion. Among these, chlorine ion, methyl sulfate ion, and ethyl sulfate ion are preferable. Any of these quaternary ammonium compounds can be produced by a usual method.

(Softener for paper)
The softener for paper of the present invention comprises the above divalent to hexavalent polyhydric alcohol (a) (component a) and the compound (b) (component b). Or it consists of said a component, said b component, and said quaternary ammonium compound (c) (c component).

  In the paper softener of the present invention, the mass ratio of the component a and the component b is 95/5 to 99.5 / 0.5, preferably 96/4 to 99/1. When the mass ratio of the component a and the component b is less than 95/5, the resulting paper softener imparts flexibility and moisturizing feeling to the paper, but the viscosity of the softener becomes high and handling becomes difficult. There is a case. When the mass ratio of the a component and the b component exceeds 99.5 / 0.5, the obtained paper softener decreases the paper strength, and further, the effect of improving flexibility becomes insufficient.

  When the paper softener of the present invention comprises the a component, the b component, and the c component, the mass ratio of the a component to the b component is 95/5 to 99.5 / 0.5, and Mass ratio with c component is 95/5-99.5 / 0.5. The softening agent for paper in which the mass ratio of the component a and the component c is in such a range further increases the flexibility improvement effect.

  The paper softener of the present invention is applied to sanitary paper base paper by, for example, a transfer printing method, a coater, a spraying method or the like, preferably a transfer printing method. When manufacturing sanitary paper that is processed in two layers, a paper softener may be applied to the sanitary paper base, and then two sheets may be processed. A softener may be applied.

  When paper is produced using the paper softener of the present invention, the paper softener may be used as it is, or the viscosity may be adjusted with a solvent.

  The present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

(Synthesis Example 1: Synthesis of Compound (b))
(Synthesis Example 1.1)
Into a 500 mL four-necked flask equipped with a stirrer, a condenser, a thermometer, and a nitrogen inlet tube, 234 g (1.8 mol) of amine (diethylaminopropylamine) and 131.5 g of adipic acid (Table 1) 0.9 mol) was charged. Next, the temperature was raised to 120 to 130 ° C. with stirring in a nitrogen atmosphere, and the reaction was performed for 15 hours while removing the generated water out of the system to obtain Compound b-1 having an amine value of 299.

(Synthesis Examples 1.2 and 1.3)
Compounds b-2 and b-3 were obtained in the same procedure as in Synthesis Example 1.1 except that the amines (1.8 mol) and dicarboxylic acids (0.9 mol) listed in Table 1 were used. .

(Comparative Synthesis Example 1)
Compound b′-1 was obtained in the same procedure as in Synthesis Example 1.1 except that the amine (1.8 mol) and dicarboxylic acid (0.9 mol) shown in Table 1 were used.

(Synthesis Example 2: Synthesis of quaternary ammonium compound)
In a four-necked flask equipped with a stirrer, a condenser, a thermometer, and a nitrogen inlet tube, a mixed fatty acid (9.8% by weight palmitic acid, 39.8% by weight stearic acid, 45.6% by weight olein) was added. 280 g (1 mol) of acid, 3.2 wt% linoleic acid, and 1.6 wt% of other fatty acids) and 74.5 g (0.5 mol) of triethanolamine were charged. Subsequently, the temperature was raised to 180 ° C. in a nitrogen atmosphere, and the reaction was performed for 15 hours while removing the generated water out of the system to obtain an ester compound having a hydroxyl value of 87.2 and an amine value of 81.5. Next, 134.7 g (0.2 mol) of the obtained ester compound and 159.8 g of ethanol were charged into a reaction vessel equipped with a stirrer and a thermometer, and the temperature was raised to 60 ° C. to raise the gas phase portion in the reaction vessel. Was replaced with nitrogen. Next, the temperature was raised to 70 ° C. with stirring, 25.1 g (0.2 mol) of dimethylsulfuric acid was added, and the mixture was reacted for 2 hours. An ester type quaternary ammonium compound represented by the above general formula (6) was obtained.

  Furthermore, as a quaternary ammonium compound (an alkyl type quaternary ammonium compound represented by the above general formula (2)), a commercially available cation AB (stearyltrimethylammonium chloride: manufactured by NOF Corporation) and a cation 2OLR (Dioleyldimethylammonium chloride: manufactured by NOF Corporation) was used. These quaternary ammonium compounds were designated as c-2 and c-3, respectively.

(Example 1: Preparation and evaluation of aqueous solution of paper softener)
1. Preparation of aqueous solution of paper softener In a 500 mL four-necked flask equipped with a stirrer, a condenser tube, and a thermometer, 266 g of glycerol (70% by mass) and 38 g of propylene glycol (10% by mass) listed in Table 3 , 64.1 g (17.2% by mass) of ion-exchanged water, and 4.3 g (0.8% by mass) of 70% glycolic acid were charged. Next, after stirring at 50 ° C. for 15 minutes, 7.6 g (2% by mass) of compound b-1 was added, and further stirred at 50 ° C. for 15 minutes to obtain an aqueous solution I of a paper softener.

2. 2. Evaluation of softener for paper 2-1. Preparation of soft paper (tissue paper) Using the obtained aqueous solution I of softener for paper, soft paper (tissue paper) was prepared as follows.

  An aqueous solution I of a paper softener was uniformly applied to a glass plate having a smooth surface. Next, one piece of commercially available tissue paper (one set of two commercially available sheets is one piece) is placed on a glass plate, and a metal rod is rolled over the tissue paper to apply force. The agent was transferred to tissue paper. From the difference in the mass of the tissue paper before and after the transfer of the softening agent, the a component and the b component were applied in a total of 20% by mass. In this manner, five tissue papers coated with a softening agent were prepared and stored for 48 hours in a constant temperature and humidity chamber at a temperature of 23 ° C. and a humidity of 50%.

2-2. Evaluation (1) Softness, (2) Moisturizing feeling, and (3) Paper strength (tensile strength) of tissue paper coated with a softener were evaluated by the following methods.

(1) Flexibility Five tissue papers coated with a softening agent were stacked and touched by an evaluator (10 women) with one hand. And the touch (flexibility) when touched was evaluated according to the following evaluation criteria. The average score of 10 evaluators was used as an evaluation value, and a case where the evaluation value was 3.0 or more was evaluated as ◯ (tissue paper excellent in flexibility). The results are shown in Table 3.

(Evaluation criteria)
5 points: When feeling very soft.
4 points: When feeling soft.
3 points: When feeling slightly soft.
2 points: When felt to be equivalent to untreated softener (commercially available tissue paper).
1 point: When there is no softness and it is hard.

(2) Moisturizing feeling Five tissue papers coated with a softening agent were stacked and touched by an evaluator (10 women) with one hand. And the touch (moisturizing feeling) when touched was evaluated according to the following evaluation criteria. The average value of 10 evaluators was used as an evaluation value, and a case where the evaluation value was 3.0 or more was evaluated as ◯ (tissue paper excellent in moisturizing feeling). The results are shown in Table 3.

(Evaluation criteria)
5 points: When you feel very moist.
4 points: When you feel moist.
3 points: If you feel a little moist.
2 points: When felt to be equivalent to untreated softener (commercially available tissue paper).
1 point: When there is no moist feeling.

(3) Paper strength (tensile strength)
The tissue paper coated with the softening agent was cut into 120 × 15 mm, and the tensile strength when the paper was separated was measured using a tensile / compression tester SV-201-0-SH (manufactured by Imada Manufacturing Co., Ltd.). The measurement results were evaluated according to the following evaluation criteria. The results are shown in Table 3.

(Evaluation criteria)
Tensile strength is 1.35 N or more: paper strength is maintained (◯).
Tensile strength is less than 1.35 N: paper strength is reduced (x).

(Examples 2 to 5)
Except that the polyhydric alcohol (a), compound (b), acid, and quaternary ammonium compound (c) listed in Table 3 were used in the proportions described in Table 3, the same procedure as in Example 1 was used. Paper softener aqueous solutions II to V were obtained, respectively. Next, using these aqueous solutions II to V, a tissue paper coated with a softening agent was prepared in the same procedure as in Example 1, and the evaluations (1) to (3) were performed. The results are shown in Table 3.

(Comparative Example 1)
Evaluation of said (1)-(3) was performed using commercially available tissue paper. The results are shown in Table 4.

(Comparative Examples 2 to 4)
The same procedure as in Example 1 except that the polyhydric alcohol (a), the compound b′-1, the acid, and the quaternary ammonium compound (c) described in Table 4 were used in the ratios described in Table 4. Respectively obtained aqueous solutions VI to VIII of the paper softener. Next, using these aqueous solutions VI to VIII, tissue paper coated with a softening agent was prepared in the same procedure as in Example 1, and the evaluations (1) to (3) were performed. The results are shown in Table 4.

  As shown in Table 3, when using the paper softener aqueous solutions I to V of Examples, it can be seen that any tissue paper has excellent flexibility and moisturizing feeling while maintaining paper strength. .

  On the other hand, as shown in Table 4, the tissue paper using the softeners of Comparative Examples 2 to 4 was insufficient in any of flexibility, moisture retention, and paper strength. That is, in Comparative Example 2, since only the polyhydric alcohol (a) was applied, a tissue paper excellent in flexibility could not be obtained, and the paper strength was greatly reduced. In Comparative Example 3, since the amidoamine compound obtained from diethylenetriamine and sebacic acid was used instead of the compound (b) in the preparation of the paper softener, a tissue paper excellent in flexibility could not be obtained. In Comparative Example 4, since the paper softener containing only the polyhydric alcohol (a) and the quaternary ammonium compound (c) and not containing the b component was used, the obtained tissue paper had greatly reduced paper strength. .

  ADVANTAGE OF THE INVENTION According to this invention, the softening agent for papers which can provide the softness | flexibility and moisture retention which were excellent in paper, without reducing paper strength is provided. When this paper softener is used, paper having excellent flexibility and moisture retention can be obtained while maintaining paper strength. The obtained paper is widely used as sanitary paper such as tissue paper and toilet paper.

Claims (2)

A paper softener comprising a divalent to hexavalent polyhydric alcohol (a) and a compound (b),
The mass ratio of the polyhydric alcohol (a) to the compound (b) is 95/5 to 99.5 / 0.5;
The compound (b) is represented by the following general formula (1):

(A is a residue of a dicarboxylic acid having 4 to 12 carbon atoms, R ¹ , R ² , R ⁵ , and R ⁶ are each an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ Are each an alkylene group having 2 to 4 carbon atoms). A paper softener comprising a divalent to hexavalent polyhydric alcohol (a), a compound (b), and a quaternary ammonium compound (c),
The mass ratio of the polyhydric alcohol (a) to the compound (b) is 95/5 to 99.5 / 0.5, and the polyhydric alcohol (a) and the quaternary ammonium compound (c ) And the mass ratio of 95/5 to 99.5 / 0.5,
The compound (b) is represented by the following general formula (1):

(A is a residue of a dicarboxylic acid having 4 to 12 carbon atoms, R ¹ , R ² , R ⁵ , and R ⁶ are each an alkyl group having 1 to 4 carbon atoms, and R ³ and R ⁴ Are each an alkylene group having 2 to 4 carbon atoms).