JP4710593B2 - Softener for paper and method for producing soft paper using the same - Google Patents

Description

  The present invention relates to a paper softener and a method for producing a soft paper using the same. More specifically, the present invention relates to a softening agent for paper that can improve flexibility and develop sufficient size without reducing paper strength, and a method for producing flexible paper using the same.

  In recent years, in the paper manufacturing industry, the visualization and colorization of printed matter has progressed, and printing paper with good flexibility is demanded from the viewpoint of improving printability. In addition, more flexible printing paper has been demanded from the viewpoint of easy turning of pages of printed materials such as books. On the other hand, in the paper manufacturing industry, in order to increase productivity, the paper manufacturing process and the printing process are accelerated. Generally, a paper softener is used for the purpose of imparting flexibility to paper. However, paper with improved flexibility due to the use of softeners, on the other hand, is also known to have reduced paper strength such as tensile strength, which may be disadvantageous when speeding up papermaking and printing processes. is there.

  Furthermore, as softeners developed so far, for example, softeners using polyethylene glycol, urea, quaternary ammonium salts and the like are known. However, such a softening agent cannot impart sufficient sizing properties to the paper due to the influence of the hydrophilic group in the molecule, and even when the softening agent and the sizing agent are used in combination, There may also be a problem that sufficient size cannot be obtained.

In order to solve the above-mentioned problem, a method for improving flexibility and developing size properties using a mixture of an ester compound of a polyhydric alcohol and a higher unsaturated fatty acid and a sizing agent (for example, Patent Document 1), amino A method using ammonium salt to improve flexibility while suppressing a decrease in paper strength (for example, Patent Document 2), a method using acrylamide polymer and sizing agent to improve paper strength and size (for example, Patent Document) 3) etc. have been reported. However, none of the papers has sufficient flexibility, size, and paper strength. Therefore, a paper softener capable of obtaining paper (particularly printing paper) excellent in flexibility, size, and paper strength is demanded.
JP 2004-324024 A JP 2001-355197 A Japanese Patent Laid-Open No. 2003-238631

  An object of the present invention is to provide a paper softener capable of imparting excellent flexibility and size to paper without reducing the paper strength of the paper. Another object of the present invention is to provide a method for efficiently producing paper using the paper softener.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have obtained a condensate obtained by reacting two kinds of amidoamine compounds having different amidation ratios and urea in a specific molar ratio at a specific ratio. It was found that a paper softener capable of achieving the above-mentioned purpose can be obtained by combining acrylamide polymers having a weight average molecular weight of 100,000 to 3 million at a specific ratio. Furthermore, a paper manufacturing method using this paper softening agent has been obtained. The present invention has been completed based on such findings.

The paper softener of the present invention is a paper softener comprising a condensate (A) of an amidoamine compound and urea and an acrylamide polymer (B) having a weight average molecular weight of 100,000 to 3,000,000. The mass ratio of the product (A) to the acrylamide polymer (B) is 60:40 to 99: 1, and the condensate (A) is a mole of the amidoamine compound (d) and the amidoamine compound (e). It is obtained by reacting an amidoamine compound having a ratio of 30:70 to 90:10 with 0.1 to 1 molar equivalent of urea with respect to 1 mol of the amino group of the amidoamine compound, and the amidoamine compound (d) However, the following formula (1):
R ¹ NH— (R ² —NH) _m —R ³ (1)
(R ¹ and R ³ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is an alkylene group having 1 to 4 carbon atoms, and m is 2 to 4). A polyamine compound (1) and a carboxylic acid having 10 to 24 carbon atoms containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms, based on 1 mol of the amino group of the polyamine compound (1) And the amide amine compound (e) is obtained by reacting at a ratio such that the carboxyl group of the carboxylic acid is 0.6 to 0.85 molar equivalent.
_{^{R 4 NH- (R 5 -NH)}} n -R 6 (2)
(R ⁴ and R ⁶ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁵ is an alkylene group having 1 to 4 carbon atoms, and n is 2 to 4) A polyamine compound (2) and a carboxylic acid having 10 to 24 carbon atoms, containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms,
The polyamine compound (2) is obtained by reacting at a ratio such that the carboxyl group of the carboxylic acid is 0.2 to 0.45 molar equivalent with respect to 1 mol of the amino group of the polyamine compound (2).

The paper softener of the present invention also includes a condensate (A) of an amidoamine compound and urea, an acrylamide polymer (B) having a weight average molecular weight of 100,000 to 3 million, and a saturated or A paper softener comprising an alkyl ketene dimer (C) comprising an unsaturated carboxylic acid, wherein the mass ratio of the condensate (A) to the acrylamide polymer (B) is from 60:40 to 99: 1. And the mass ratio of the total amount of the condensate (A) and the acrylamide polymer (B) to the alkyl ketene dimer (C) is 50:50 to 99: 1, and the condensate (A ) Is an amide amine compound in which the molar ratio of the amide amine compound (d) and the amide amine compound (e) is 30:70 to 90:10, and 0.1 to 1 mol relative to 1 mol of the amino group of the amide amine compound. Equivalent Obtained by reacting a hydrogen, the amidoamine compound (d) is the following formula (1):
R ¹ NH— (R ² —NH) _m —R ³ (1)
(R ¹ and R ³ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is an alkylene group having 1 to 4 carbon atoms, and m is 2 to 4). A polyamine compound (1) and a carboxylic acid having 10 to 24 carbon atoms containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms, based on 1 mol of the amino group of the polyamine compound (1) And the amide amine compound (e) is obtained by reacting at a ratio such that the carboxyl group of the carboxylic acid is 0.6 to 0.85 molar equivalent.
_{^{R 4 NH- (R 5 -NH)}} n -R 6 (2)
(R ⁴ and R ⁶ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁵ is an alkylene group having 1 to 4 carbon atoms, and n is 2 to 4) A polyamine compound (2) and a carboxylic acid having 10 to 24 carbon atoms and containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms, based on 1 mol of the amino group of the polyamine compound (2) The carboxylic acid is obtained by reacting at a ratio such that the carboxyl group of the carboxylic acid is 0.2 to 0.45 molar equivalent.

  In the paper manufacturing method of the present invention, the total amount of the condensate (A) and the acrylamide polymer (B) is 0.03 to 8 masses per 100 parts by mass of the pulp. The process of adding so that it may become a part is included.

  The paper softener of the present invention can impart excellent flexibility and size to paper without reducing the paper strength of the paper.

  The paper softener of the present invention comprises a condensate (A) of an amidoamine compound and urea (hereinafter sometimes referred to as component A) and an acrylamide polymer (B) having a weight average molecular weight of 100,000 to 3 million (hereinafter referred to as “component A”). , Sometimes referred to as B component). Alternatively, it comprises a condensate (A) of an amidoamine compound and urea, the acrylamide polymer (B), and an alkyl ketene dimer (C) (hereinafter sometimes referred to as C component). Hereinafter, each component, a paper softener, and a paper manufacturing method using the same will be described.

(Condensate (A); Component A)
The condensate (A) of an amidoamine compound and urea can be obtained by reacting two kinds of amidoamine compounds having different amidation rates with urea at a specific ratio. In the present invention, in particular, one of the features is that two types of amidoamine compounds (d) and (e) having different amidation rates are used in a specific molar ratio.

(1) Amidoamine compound As the raw material of the condensate (A), as described above, two types of amidoamine compounds having different amidation rates, that is, an amidoamine compound (d) having a relatively high amidation rate, are used. An amidoamine compound (e) having a lower amidation rate than the amidoamine compound (d) is used. In this specification, an amidation rate means the molar equivalent of the carboxyl group of carboxylic acid with respect to 1 mol of amino groups of the polyamine compound used for manufacture of an amidoamine compound. Therefore, this amidation rate can be adjusted, for example, by the ratio of the polyamine compound and the carboxylic acid. Hereinafter, the amidoamine compounds (d) and (e) will be described first, and then the ratio of the amidoamine compounds (d) and (e) will be described.

(1-1) Amidoamine compound (d)
The polyamine compound (1) used for the production of the amidoamine compound (d) has the following general formula (1):
R ¹ NH— (R ² —NH) _m —R ³ (1)
(R ¹ and R ³ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is an alkylene group having 1 to 4 carbon atoms, and m is 2 to 4). .

In the general formula (1), examples of the alkyl group having 1 to 3 carbon atoms of R ¹ and R ³ include a methyl group, an ethyl group, a propyl group, and an isopropyl group.

In the general formula (1), examples of the alkylene group having 1 to 4 carbon atoms of R ² include a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, and a butylene group.

  The carboxylic acid used for the production of the amidoamine compound (d) is a carboxylic acid having 10 to 24 carbon atoms containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms. Carbon number of the carboxylic acid is preferably 12-18. When the number of carbon atoms is less than 10, the resulting softening agent for paper has insufficient flexibility and size improvement effects. When the number of carbon atoms exceeds 24, the paper softener using such an amidoamine compound has the effect of imparting flexibility and size to the paper, but the resulting amidoamine compound has a high melting point and is difficult to handle. It may become. When the content of the saturated carboxylic acid is less than 35% by mass, the effect of improving the size of the obtained paper softener becomes insufficient.

  Examples of the carboxylic acid having 10 to 24 carbon atoms include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, tetracosanoic acid and the like; palmitoleic acid, oleic acid, linoleic acid, Examples thereof include unsaturated carboxylic acids such as linolenic acid and erucic acid.

  In the amidoamine compound (d), the carboxyl group of the carboxylic acid is 0.6 to 0.85 with respect to 1 mol of the amino group of the polyamine compound (1). It is obtained by reacting at a molar equivalent, preferably 0.6 to 0.75 molar equivalent. When the amount is less than 0.6 molar equivalent, the effect of improving the flexibility and size of the obtained paper softener is insufficient. When it exceeds 0.85 molar equivalent, the effect of improving the flexibility of the obtained paper softener becomes insufficient. The reaction for obtaining the amidoamine compound (d) is carried out, for example, by charging the polyamine compound (1) and the carboxylic acid in a reactor, heating the mixture with stirring in a nitrogen atmosphere, and removing generated water. While holding for several hours.

(1-2) Amidoamine compound (e)
The polyamine compound (2) used in the production of the amidoamine compound (e) has the following general formula (2):
_{^{R 4 NH- (R 5 -NH)}} n -R 6 (2)
(R ⁴ and R ⁶ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁵ is an alkylene group having 1 to 4 carbon atoms, and n is 2 to 4) .

In the general formula (2), for the alkyl group having 1 to 3 carbon atoms of R ⁴ and R ⁶ , the same alkyl group as R ¹ and R ^{3 in} the formula (1) can be used. For the alkylene group having 1 to 4 carbon atoms in R ⁵ , the same alkylene group as R ^{2 in the} above formula (1) can be used.

  The carboxylic acid used for the production of the amidoamine compound (e) is a carboxylic acid having 10 to 24 carbon atoms containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms. Carbon number of the carboxylic acid is preferably 12-18. When the number of carbon atoms is less than 10, the resulting softening agent for paper has insufficient flexibility and size improvement effects. When the number of carbon atoms exceeds 24, the paper softener using such an amidoamine compound has the effect of imparting flexibility and size to the paper, but the resulting amidoamine compound has a high melting point and is difficult to handle. It may become. When the content of the saturated carboxylic acid is less than 35% by mass, the effect of improving the size of the obtained paper softener becomes insufficient. Examples of such carboxylic acids having 10 to 24 carbon atoms include carboxylic acids used in amidoamine compounds (d).

  In the amidoamine compound (e), the carboxyl group of the carboxylic acid is 0.2 to 0.45 with respect to 1 mol of the amino group of the polyamine compound (2). It is obtained by reacting at a molar equivalent, preferably 0.25 to 0.4 molar equivalent. When the amount is less than 0.2 molar equivalent, the effect of improving the flexibility and size of the obtained paper softener is insufficient. When it exceeds 0.45 molar equivalent, the effect of improving the flexibility of the obtained paper softener becomes insufficient. The reaction for obtaining the amidoamine compound (e) can be performed, for example, in the same manner as the amidoamine compound (d).

  The amidoamine compound has a molar ratio of the amidoamine compound (d) to the amidoamine compound (e) of 30:70 to 90:10, preferably 35:65 to 70:30. When the molar ratio is out of the range of 30:70 to 90:10, the effect of improving the flexibility of the obtained paper softener becomes insufficient.

(2) Urea As the urea that is the raw material of the condensate (A), a commercially available product can be used as appropriate.

(3) Condensation reaction (Preparation of condensate (A))
In the condensate (A), the amidoamine compound and the urea are mixed in an amount of 0.1 to 1 mole equivalent, preferably 0.3 to 0.7 mole equivalent, of urea with respect to 1 mole of the amino group of the amidoamine compound. It is obtained by reacting at such a ratio. When urea is less than 0.1 molar equivalent, the effect of improving the size of the resulting paper softener is insufficient. When the urea exceeds 1 molar equivalent, the effect of improving the flexibility and size according to the amount used is I can't get it. The condensate (A) is prepared by a normal condensation reaction.

  The condensate (A) is preferably made into a salt by reacting an unreacted amine moiety with an inorganic acid or an organic acid in order to facilitate the preparation of a paper softener dispersion. Examples of the inorganic acid include hydrochloric acid, sulfuric acid, carbonic acid, nitric acid, phosphoric acid and the like. Organic acids include formic acid, acetic acid, propionic acid, octylic acid, butyric acid, oxalic acid, malonic acid, itaconic acid, adipic acid, succinic acid, sebacic acid, citric acid, hydroxybenzoic acid, malic acid, hydroxymalonic acid, lactic acid , Gluconic acid, salicylic acid, hydroxyvaleric acid, aspartic acid, glutamic acid, taurine, sulfamic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid and the like. Among these, organic acids are preferable, and formic acid, acetic acid, and propionic acid are particularly preferable. You may perform this reaction by an acid, when preparing a paper softening agent.

(Acrylamide polymer (B); B component)
As the acrylamide polymer (B), an acrylamide polymer having a weight average molecular weight of 100,000 to 3,000,000, preferably 300,000 to 2.7 million, more preferably 1,000,000 to 2,000,000 is used. When the weight average molecular weight is less than 100,000, the size imparting effect of the obtained paper softener becomes insufficient. When the weight average molecular weight exceeds 3 million, the resulting softener for paper has the effect of imparting flexibility and size to the paper, but is difficult to handle.

  Examples of the acrylamide polymer include anionic polyacrylamide, cationic polyacrylamide, and amphoteric polyacrylamide. Cationic polyacrylamide and amphoteric polyacrylamide are preferred.

  Examples of the anionic polyacrylamide include a copolymer of acrylamide and an anionic monomer (such as acrylic acid or methacrylic acid), a partial hydrolyzate of polyacrylamide, and the like.

  As cationic polyacrylamide, Mannich modified product of polyacrylamide, Hoffman degradation product, or acrylamide and cationic monomer (dimethylaminoethyl methacrylate, diallyldimethylammonium chloride, diallyldiethylammonium chloride, methacryloyloxyethyltrimethylammonium methyl sulfate, And a copolymer with methacryloyloxyethyltrimethylammonium methyl chloride, methacrylamidopropyltrimethylammonium chloride, etc.).

  Examples of amphoteric polyacrylamides include copolymers of acrylamide with the above-mentioned anionic monomers and cationic monomers, Mannich-modified products and Hofmann-decomposed products of copolymers of acrylamide and the above-mentioned anionic monomers.

(Alkyl ketene dimer (C); component C)
The alkyl ketene dimer (C) is used to impart additional sizing properties (water resistance) to the paper. The alkyl ketene dimer (C) can be obtained, for example, by converting a carboxylic acid into a chloride of carboxylic acid by a phosphorus method or a phosgene method, and then dehydrochlorinating with a tertiary amine as a catalyst.

  Examples of the carboxylic acid used as the raw material for the alkyl ketene dimer (C) include saturated or unsaturated carboxylic acids having 12 to 24 carbon atoms, preferably 14 to 18 carbon atoms. When the number of carbon atoms of the carboxylic acid is less than 12, it may not be possible to expect a further improvement in size, and when it exceeds 24, handling of the resulting paper softener may be difficult.

  Examples of the saturated carboxylic acid include lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, arachidic acid, behenic acid, and tetracosanoic acid. Examples of the unsaturated carboxylic acid include palmitoleic acid, oleic acid, erucic acid and the like. These carboxylic acids may be used alone or in combination of two or more.

(Softener for paper)
The paper softener of the present invention comprises a condensate (A component) of the amidoamine compound and urea and an acrylamide polymer (B component) having a weight average molecular weight of 100,000 to 3 million. Or it consists of A component, B component, and an alkyl ketene dimer (C component).

  In the paper softener of the present invention, the mass ratio of the A component and the B component is 60:40 to 99: 1, preferably 70:30 to 85:15. When the ratio of the acrylamide polymer (B) is less than 1 part by mass, the paper strength is insufficient. When it exceeds 40 parts by mass, the workability of the resulting paper softener is lowered, and the effect of improving the flexibility of the paper softener is insufficient.

  When the paper softener of the present invention comprises an A component, a B component, and a C component, the mass ratio of the total amount of the A component and the B component to the C component is 50:50 to 99: 1. Preferably it is 70: 30-95: 5.

  The paper softener of the present invention is preferably used as a dispersion liquid dispersed in a solvent such as water. The dispersion is prepared using an emulsifier such as a high-pressure homogenizer after mixing with additives such as a dispersant and protective colloid.

(Paper manufacturing method)
The paper manufacturing method of the present invention is characterized in that the paper softener is used in paper manufacture. The total amount of the condensate (A) and the acrylamide polymer (B) is 0.03 to 8 parts by mass, preferably 0.1 to 5 parts by mass, with respect to 100 parts by mass of pulp. Add to part. When the total amount of the condensate (A) and the acrylamide polymer (B) is less than 0.03 parts by mass, sufficient flexibility and size cannot be imparted to the paper. When the total amount of the condensate (A) and the acrylamide polymer (B) exceeds 8 parts by mass, the effect of improving the flexibility and sizing property corresponding to the amount used cannot be obtained, but rather the cost of the paper is increased. Connection is economically disadvantageous.

  Examples of the pulp (raw pulp) include chemical pulp (exposed or unexposed kraft pulp of softwood or hardwood), mechanical pulp (such as ground pulp, thermomechanical pulp, chemithermomechanical pulp), deinked pulp (newspaper, magazine) Used paper). These can be used alone or in combination.

  The paper softener of the present invention can be used in various processes in the production of paper. That is, it can be added to the papermaking system at any stage of the papermaking process (internal addition method), and can also be applied to the surface of the pulp sheet obtained by the papermaking process (external addition method). For example, the internal addition method that is added to the pulp slurry in the mixing chest, machine chest, seed box, etc. in the paper making process, or the size press, gate roll, spray, etc. that are applied to the pulp sheet surface obtained by paper making The addition method is adopted.

  In particular, the internal addition method is preferably employed. For example, a paper can be obtained by adding the paper softener to a mixture containing pulp and water (for example, pulp slurry) and making paper by a usual method.

  In the paper manufacturing method of the present invention, paper machines such as a long net paper machine, a twin wire machine, and a Yankee machine, which are generally used for paper making, can be used.

  Examples of the paper manufactured by the paper manufacturing method of the present invention include newsprint paper, printing paper, recording paper, packaging paper, paperboard, liner, corrugated paper such as a core, wallpaper, base paper, backing paper, and the like. Examples include sanitary paper such as paper products, toilet paper, and tissue paper. In particular, printing paper is suitable.

  The present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Hereinafter, the amidoamine compound (d) is referred to as an amidoamine compound d, and the amidoamine compound (e) is referred to as an amidoamine compound e.

(Synthesis Example 1.1: Synthesis of Amidoamine Compound d)
A 500 mL four-necked flask equipped with a stirrer, a condenser, a thermometer, and a nitrogen inlet tube was charged with 50.4 g (0.27 mol) of the polyamine compound shown in Table 1 and 287.5 g (1 mol) of stearic acid. The mixture was heated to 180 to 190 ° C. with stirring in a nitrogen atmosphere, and reacted for 3 hours while removing generated water out of the system to obtain an amidoamine compound d-1 having a total amine value of 59.0.

(Synthesis Examples 1.2 to 1.5)
Amidoamine compounds d-2 to d-5 were obtained in the same manner as in Synthesis Example 1.1, except that the polyamine compounds and carboxylic acids shown in Table 1 were used in the proportions shown in Table 1.

(Synthesis Example 1.6: Synthesis of Amidoamine Compound e)
The total amine value is 321.2 in the same manner as in Synthesis Example 1.1 except that 100.9 g (0.98 mol) of the polyamine compound shown in Table 1 and 256.2 g (1 mol) of palmitic acid were used. Amidoamine compound e-1 was obtained.

(Synthesis Examples 1.7 to 1.10)
Amidoamine compounds e-2 to e-5 were obtained in the same manner as in Synthesis Example 1.1, except that the polyamine compounds and carboxylic acids shown in Table 1 were used in the proportions shown in Table 1.

(Comparative Synthesis Examples 1.1 to 1.2)
Amidoamine compounds f-1 to f-2 were obtained in the same manner as in Synthesis Example 1.1, except that the polyamine compounds and carboxylic acids shown in Table 1 were used in the proportions shown in Table 1.

(Comparative Synthesis Examples 1.3 to 1.4)
Amidoamine compounds f-3 to f-4 were obtained in the same manner as in Synthesis Example 1.6 except that the polyamine compounds and carboxylic acids shown in Table 1 were used in the proportions shown in Table 1.

(Synthesis Example 2.1: Synthesis of condensate)
In a 500 mL four-necked flask equipped with a stirrer, a condenser tube, a thermometer, and a nitrogen inlet tube, 237.3 g (0.2 mol) of the amidoamine compound d-1 obtained in the above synthesis example, and the amidoamine compound e -1 was charged to 69.1 g (0.2 mol), and the temperature was raised to 110 to 120 ° C. with stirring in a nitrogen atmosphere. The amine value of this mixed amidoamine compound was 190.0. Next, 21.0 g (0.35 mol) of urea was further charged, and the mixture was stirred at 160 ° C. to 170 ° C. in a nitrogen atmosphere, and reacted for 1 hour while removing ammonia out of the system. The total amine value was 76.0. The condensate A-1 was obtained. The results are shown in Table 2.

(Synthesis Examples 2.2 to 2.5)
Condensates A-2 to A-5 were obtained in the same manner as in Synthesis Example 2.1 except that amidoamine compounds d and e shown in Table 2 and urea were used. The results are shown in Table 2.

(Comparative Synthesis Examples 2.1 to 2.7)
Condensates A-6 to A-12 were obtained in the same manner as in Synthesis Example 2.1 except that the amidoamine compounds and urea listed in Table 2 were used. The results are shown in Table 2.

  Various condensates as shown in Table 2 were obtained. Among these, the condensates of Comparative Synthesis Examples 2.1 to 2.7 do not satisfy the conditions of the condensate used in the present invention. That is, the condensates of Comparative Synthesis Examples 2.1 to 2.4 do not contain any of the amidoamine compounds d and e. In the condensates of Comparative Synthesis Examples 2.5 and 2.6, the ratio (molar ratio) of amidoamine compounds d and e is not appropriate. In the condensate of Comparative Synthesis Example 2.7, the ratio of urea to the amino group of the amidoamine compound is small.

(Example 1: Preparation of paper softener dispersion and evaluation thereof)
1. Preparation of Dispersion of Softener for Paper In a 1 L beaker, 439.2 g of ion exchange water, 56.0 g of condensate A-1 (component A) obtained in Synthesis Example 2.1, and 4.78 g of acetic acid (condensate) 200.0 g of a 7% by mass aqueous solution of the acrylamide polymer (component B) shown in Table 3 was added, and the temperature was raised to 80 ° C. Subsequently, it processed for 5 minutes at 5000 rpm using a homomixer (made by Tokushu Kika Kogyo Co., Ltd.), and also 2 at 40 MPa using a pressure emulsifier (made by Manton Gorin, APV GAULIN, INC.). The paper softening agent dispersion liquid was prepared by carrying out the reprocessing (referred to as dispersion liquid G-1). Dispersion G-1 contains 10% by mass of the condensate (component A) and the acrylamide polymer (component B) in total.

2. Evaluation of Softener for Paper Using the dispersion G-1 obtained above, a handsheet was produced as follows, and the flexibility (bending stiffness and capacity), size, and size of the obtained handsheet Paper strength was evaluated.

2-1. Manufacture of handsheets LBKP (hardwood bleached pulp) having a freeness of 400 mL was disaggregated using a disaggregator (manufactured by Kumagai Riken Co., Ltd.) to prepare a pulp slurry containing 1% by mass of pulp. 100 g of this pulp slurry (1 g of pulp amount) is put in a 200 mL capacity beaker, and 0.05 g of the above paper softener dispersion G-1 (total amount of condensate and acrylamide polymer with respect to 100 parts by mass of pulp) Is 0.5 parts by mass) and 1.0 g of a paste obtained by diluting cationized starch (Ace K-100, manufactured by Oji Cornstarch Co., Ltd.) with water to 1% by mass (100 parts by mass of pulp). 1.0 mass part) was added, and it stirred at 250 rpm for 1 minute with the turbine blade of diameter 4.5cm. Then, after making paper with a TAPPI standard sheet machine (Yasuda Seiki Co., Ltd.) and using a hydraulic press machine (Yasuda Seiki Co., Ltd.) for 5 minutes at 0.35 Mpa, a drum dryer (Yasuda Seiki Co., Ltd.) ) Was dried at 105 ° C. for 2 minutes to produce a handsheet having a basis weight of about 50 g / m ² . The handsheet was further stored for 17 hours in a constant temperature and humidity chamber at a temperature of 23 ° C. and a humidity of 50% to adjust the humidity.

2-2. Evaluation The flexibility (bending stiffness and capacity), size, and paper strength of the handsheets obtained were evaluated by the following methods. The results are shown in Table 5.

(1) Flexibility evaluation 1 (bending stiffness)
Using a pure bending tester (KES-FB2, manufactured by Kato Tech Co., Ltd.), the bending stiffness in the vertical direction and the horizontal direction of the handsheet was measured to obtain an average value. The average value obtained was evaluated according to the following criteria.

(Evaluation criteria)
Flexural rigidity is less than 4.41 × 10 ⁻⁵ N · m ² / m: Good flexibility (◯)
Flexural rigidity is 4.41 × 10 ⁻⁵ N · m ² / m or more: Insufficient flexibility (×)

(2) Flexibility evaluation 2 (capacity)
The basis weight of the handsheet was measured according to JIS P8124. Further, the thickness was measured using a JIS paper pressure measuring device MEI-10 (manufactured by Citizen Watch Co., Ltd.). The sheet capacity was obtained from the following equation using the obtained basis weight and thickness measurement values, and evaluated according to the following criteria.
Sheet capacity (cm ³ / g) = thickness (μm) / basis weight (g / m ² )

(Evaluation criteria)
Sheet capacity is 1.60 cm ³ / g or more: Good flexibility (◯)
Sheet capacity is less than 1.60 cm ³ / g: insufficient flexibility (×)

(3) Evaluation of sizing properties In accordance with JIS P8122, the degree of sizing of the handsheets was measured, and the sizing properties were evaluated as follows. If it is ◎ or ○, there is no practical problem.

(Evaluation criteria)
Sizing degree is 30 seconds or more: Size is very good (◎)
Sizing degree is 20 seconds or more and less than 30 seconds: Good sizing (○)
Size is less than 20 seconds: Insufficient size (×)

(4) Evaluation of paper strength The handsheet was cut into 15 × 120 mm, and the tensile strength was measured using a tensile tester (manufactured by Imada Manufacturing Co., Ltd.). Using the obtained tensile strength and basis weight values, the tear length was calculated from the following formula (referred to as the test tear length). When the breaking length was 4.28 km or more, the paper strength was good (◯), and when it was less than 4.28 km, the paper strength was insufficient (×).

(Examples 2 to 4)
In the same manner as in Example 1 except that the condensate (component A), acrylamide polymer (component B), alkyl ketene dimer (component C), and acid described in Table 3 were used, dispersion G- 2 to G-4 were obtained. A handsheet was produced and evaluated in the same manner as in Example 1 except that the dispersions G-2 to G-4 were used so as to have the addition amounts shown in Table 3. The results are also shown in Table 5.

(Example 5)
In a 1 L beaker, 482.0 g of ion-exchanged water, 50.6 g of condensate A-3 (component A) obtained in Synthesis Example 2.3, and a mass ratio of stearic acid and palmitic acid of 65:35 10.5 g of alkyl ketene dimer (component C) using fatty acid as a raw fatty acid, 26.3 g of 10 mass% cationized starch (HI-CAT260, manufactured by Roquette Italy SPA) previously treated with sodium persulfate, Add 3.02 g of acetic acid (corresponding to 1.05 molar equivalent to the amine value of the condensate) and 127.6 g of a 7% by mass aqueous solution of the acrylamide polymer (component B) shown in Table 3 Warm up. Subsequently, it processed for 5 minutes at 5000 rpm using a homomixer (made by Tokushu Kika Kogyo Co., Ltd.), and also 2 at 40 MPa using a pressure emulsifier (made by Manton Gorin, APV GAULIN, INC.). The paper softening agent dispersion liquid was prepared by carrying out the reprocessing (referred to as dispersion liquid G-5). This dispersion G-5 contains a total of 8.5% by mass of the condensate and the acrylamide polymer, and 1.5% by mass of the alkyl ketene dimer. A handsheet was produced and evaluated in the same manner as in Example 1 using Dispersion G-5. The results are shown in Table 5.

(Examples 6 to 8)
In the same manner as in Example 5 except that the condensate (component A), acrylamide polymer (component B), alkyl ketene dimer (component C), and acid described in Table 3 were used, dispersion G- 6-G-8 were obtained. A handsheet was produced and evaluated in the same manner as in Example 1 using each dispersion. The results are also shown in Table 5.

(Comparative Example 1)
In a 1 L beaker, 455.0 g of ion-exchanged water, 70.0 g of an alkyl ketene dimer using a mixed fatty acid having a mass ratio of stearic acid and palmitic acid of 65:35 as a raw fatty acid, and 10 previously treated with sodium persulfate A mass% cationized starch (HI-CAT260, manufactured by Roquette Italy SPA) aqueous solution (175.0 g) was added, and the temperature was raised to 80 ° C. Subsequently, it processed for 5 minutes at 5000 rpm using a homomixer (made by Tokushu Kika Kogyo Co., Ltd.), and also 2 at 40 MPa using a pressure emulsifier (made by Manton Gorin, APV GAULIN, INC.). The paper softening agent dispersion was prepared by a round process (referred to as dispersion G-9). This dispersion G-9 contains about 10% by mass of alkyl ketene dimer. A handsheet was produced and evaluated in the same manner as Example 1 using Dispersion G-9. The results are shown in Table 5.

(Comparative Examples 2 to 5)
Dispersions G-10 to G-13 were prepared in the same manner as in Example 1, except that the condensate described in Table 4, the acrylamide polymer, and the acid were used. A handsheet was produced and evaluated in the same manner as in Example 1 except that the dispersions G-10 to G-13 were used so as to have the addition amounts shown in Table 4. The results are also shown in Table 5.

(Comparative Examples 6-11)
Dispersions G-14 to G-19 were prepared in the same manner as in Example 5, except that the condensate, the acrylamide polymer, the alkyl ketene dimer, and the acid described in Table 4 were used. A handsheet was produced and evaluated in the same manner as in Example 1 except that the dispersions G-14 to G-19 were used so as to have the addition amounts shown in Table 4. The results are shown in Table 5.

  From the results shown in Table 5, when the paper softener dispersions G-1 to G-8 of Examples are used, paper (handsheet) having excellent flexibility, size, and paper strength can be obtained. Recognize.

  On the other hand, the paper obtained using the paper softener dispersions G-9 to G-19 of Comparative Examples was insufficient in any of flexibility, size property and paper strength. . That is, since the dispersion G-9 of Comparative Example 1 does not contain a condensate and an acrylamide polymer, the flexibility of the paper was insufficient. Since the dispersion G-10 of Comparative Example 2 uses the amidoamine compound f-1 having a small carbon number of the carboxylic acid instead of the amidoamine compound d in the condensate A-6, the flexibility of the resulting paper and The size was insufficient. Dispersion G-11 of Comparative Example 3 is obtained because in the condensate A-7, an amidoamine compound f-2 in which the molar ratio of the carboxylic acid to the polyamine compound is not appropriate is used instead of the amidoamine compound d. The flexibility of the paper was insufficient. In the dispersion G-12 of Comparative Example 4, since the ratio (molar ratio) of the amidoamine compound d and the amidoamine compound e in the condensate A-10 was not appropriate, the flexibility of the obtained paper was insufficient. In the dispersion G-13 of Comparative Example 5, in the condensate A-12, since the ratio of urea to the amino group of the amidoamine compound was small, the resulting paper had insufficient size properties. Since the dispersion G-14 of Comparative Example 6 uses an amidoamine compound f-3 not containing a saturated carboxylic acid instead of the amidoamine compound e in the condensate A-8, the resulting paper has poor size properties. It was enough. The dispersion G-15 of Comparative Example 7 is obtained because the condensate A-9 uses an amidoamine compound f-4 in which the molar ratio of the carboxylic acid to the polyamine compound is not appropriate instead of the amidoamine compound e. The paper was not flexible and sizable. In the dispersion G-16 of Comparative Example 8, since the ratio (molar ratio) of the amidoamine compound d and the amidoamine compound e in the condensate A-11 was not appropriate, the flexibility of the obtained paper was insufficient. Since the dispersion G-17 of Comparative Example 9 did not use an acrylamide polymer, the paper strength was insufficient. Since the dispersion G-18 of Comparative Example 10 uses an acrylamide polymer having a high weight average molecular weight, the resulting paper has insufficient flexibility. In the dispersion G-19 of Comparative Example 11, since the mass ratio of the condensate to the acrylamide polymer was not appropriate, the flexibility of the obtained paper was insufficient.

  ADVANTAGE OF THE INVENTION According to this invention, the softening agent for paper which can provide the softness | flexibility and size property which were excellent in paper, without reducing the paper strength of paper is provided. When this paper softener is used, paper having excellent flexibility and size, particularly printing paper, can be obtained with sufficient paper strength. The obtained paper is widely used as paper in various fields such as bookbinding paper, newsprint paper, printing / information paper, cardboard base paper, and paperboard.

Claims (3)

A softener for paper comprising a condensate (A) of an amidoamine compound and urea and an acrylamide polymer (B) having a weight average molecular weight of 100,000 to 3 million,
The mass ratio of the condensate (A) and the acrylamide polymer (B) is 60:40 to 99: 1,
The condensate (A) is 0 with respect to an amidoamine compound having a molar ratio of the amidoamine compound (d) and the amidoamine compound (e) of 30:70 to 90:10 and 1 mol of the amino group of the amidoamine compound. Obtained by reacting with 1 to 1 molar equivalent of urea,
The amidoamine compound (d) has the following formula (1):
R ¹ NH— (R ² —NH) _m —R ³ (1)
(R ¹ and R ³ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is an alkylene group having 1 to 4 carbon atoms, and m is 2 to 4). A polyamine compound (1);
A carboxylic acid having 10 to 24 carbon atoms, containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms,
The polyamine compound (1) is obtained by reacting at a ratio such that the carboxyl group of the carboxylic acid is 0.6 to 0.85 molar equivalent to 1 mol of the amino group of the polyamine compound (1), and the amidoamine compound (e) However, the following formula (2):
_{^{R 4 NH- (R 5 -NH)}} n -R 6 (2)
(R ⁴ and R ⁶ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁵ is an alkylene group having 1 to 4 carbon atoms, and n is 2 to 4) A polyamine compound (2);
A carboxylic acid having 10 to 24 carbon atoms, containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms,
It is obtained by reacting at a ratio such that the carboxyl group of the carboxylic acid is 0.2 to 0.45 molar equivalent to 1 mol of the amino group of the polyamine compound (2).
Softener for paper. Alkyl ketene dimer (A) comprising a condensate (A) of an amidoamine compound and urea, an acrylamide polymer (B) having a weight average molecular weight of 100,000 to 3 million, and a saturated or unsaturated carboxylic acid having 12 to 24 carbon atoms C) a softening agent for paper,
The mass ratio of the condensate (A) to the acrylamide polymer (B) is 60:40 to 99: 1, and the total amount of the condensate (A) and the acrylamide polymer (B) And the mass ratio of the alkyl ketene dimer (C) is 50:50 to 99: 1,
The condensate (A) is 0 with respect to an amidoamine compound having a molar ratio of the amidoamine compound (d) and the amidoamine compound (e) of 30:70 to 90:10 and 1 mol of the amino group of the amidoamine compound. Obtained by reacting with 1 to 1 molar equivalent of urea,
The amidoamine compound (d) has the following formula (1):
R ¹ NH— (R ² —NH) _m —R ³ (1)
(R ¹ and R ³ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is an alkylene group having 1 to 4 carbon atoms, and m is 2 to 4). A polyamine compound (1);
A carboxylic acid having 10 to 24 carbon atoms, containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms,
The polyamine compound (1) is obtained by reacting at a ratio such that the carboxyl group of the carboxylic acid is 0.6 to 0.85 molar equivalent to 1 mol of the amino group of the polyamine compound (1), and the amidoamine compound (e) However, the following formula (2):
_{^{R 4 NH- (R 5 -NH)}} n -R 6 (2)
(R ⁴ and R ⁶ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ⁵ is an alkylene group having 1 to 4 carbon atoms, and n is 2 to 4) A polyamine compound (2);
A carboxylic acid having 10 to 24 carbon atoms, containing 35% by mass or more of a saturated carboxylic acid having 10 to 24 carbon atoms,
It is obtained by reacting at a ratio such that the carboxyl group of the carboxylic acid is 0.2 to 0.45 molar equivalent to 1 mol of the amino group of the polyamine compound (2).
Softener for paper.   The total amount of the condensate (A) and the acrylamide polymer (B) is 0.03 to 8 parts by mass with respect to 100 parts by mass of the pulp. The paper manufacturing method including the process added so that it may become.