JP6546799B2 - Method of producing surface sizing agent, surface sizing agent and paper - Google Patents

Description

  The present invention relates to a method for producing a surface sizing agent, a surface sizing agent, and a paper, and more particularly, to a method for producing a surface sizing agent, a surface sizing agent produced by the production method, and a surface size produced by the production method It relates to the paper obtained by using the agent.

  In the past, in the papermaking industry, surface sizing agents have been used for the purpose of imparting water resistance to paper, penetration of water, and size effects such as suppression of ink bleeding.

  For example, a surface sizing agent for paper making containing an aqueous polymer emulsion obtained by emulsion-polymerizing unsaturated monomers in the presence of starch, a polymerization initiator and a chain transfer agent is a high shear coating method (gate It has been proposed that the mechanical stability in rolls, size presses, etc. is good, the foaming at the time of coating is small, the handling workability of the product is excellent, and the size effect is excellent (for example, Reference 1.).

JP, 2014-163002, A

  In recent years, a further size effect is required more than the paper surface sizing agent of Patent Document 1.

  An object of the present invention is to use a method for producing a surface sizing agent capable of expressing a more excellent size effect, a surface sizing agent produced by the production method, and a surface sizing agent produced by the production method It is about providing the paper obtained.

The present invention
[1] A method for producing a surface sizing agent obtained by emulsion polymerization of a polymerization component (A) containing styrenes and (meth) acrylic acid esters, wherein the polymerization component (A) is a starch Emulsion polymerization is carried out in a solution containing (B) and a polyaminopolyamide resin (C), and the polyaminopolyamide resin (the total amount of the starches (B) and the polyaminopolyamide resin (C) A method for producing a surface sizing agent, characterized in that the content ratio of C) is 5% by mass to 50% by mass.
[2] The content ratio of the starch (B) and the polyaminopolyamide resin (C) is 30, relative to the total amount of the polymerization component (A), the starch (B) and the polyaminopolyamide resin (C). The method for producing a surface sizing agent according to the above [1], which is characterized by being from mass% to 60% by mass.
[3] The content ratio of the styrenes is 20% by mass to 70% by mass with respect to the total amount of the polymerization component (A), and the content ratio of the (meth) acrylic acid esters is 30% by mass to 80%. The method for producing a surface sizing agent according to the above [1] or [2], characterized in that the content is not more than% by mass.
[4] The polymerization component (A) further contains a hydrophilic group-containing monomer, and the content ratio of the hydrophilic group-containing monomer exceeds 0% by mass with respect to the total amount of the polymerization component (A). And 10% by mass or less, the method for producing a surface sizing agent according to any one of the above [1] to [3],
[5] The method for producing a surface sizing agent according to any one of the above [1] to [4], wherein the molecular terminal of the polyaminopolyamide resin (C) is capped with an end capping agent,
[6] The method for producing a surface sizing agent according to any one of the above [1] to [5], wherein the polyaminopolyamide resin (C) is modified with epichlorohydrin.
[7] A surface sizing agent produced by the method of producing a surface sizing agent according to any one of the above [1] to [6],
[8] A paper obtained by using the surface sizing agent according to the above [7].

  According to the method for producing a surface sizing agent of the present invention, it is possible to obtain a surface sizing agent capable of exhibiting a more excellent size effect.

  Therefore, the surface sizing agent of the present invention exhibits a more excellent size effect.

  And since the paper of this invention is obtained using said surface sizing agent, it is excellent in suppression of an ink bleed.

  The method for producing a surface sizing agent of the present invention emulsion-polymerizes a polymerization component (A) containing styrenes and (meth) acrylic acid esters.

  The polymerization component (A) contains styrenes and (meth) acrylic acid esters.

  Examples of styrenes include styrene, α-methylstyrene, vinyltoluene, ethylvinyltoluene, chloromethylstyrene and the like, with preference given to styrene.

  Styrenes may be used alone or in combination of two or more.

  The content ratio of styrenes is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, more preferably 40% by mass, based on the total amount of the polymerization component (A). % Or more and, for example, 80% by mass or less, preferably 70% by mass or less, more preferably 60% by mass or less, and still more preferably 50% by mass or less.

  If the content rate of styrenes is said content rate, the surface sizing agent obtained by the manufacturing method of the surface sizing agent of this invention can express the further outstanding size effect.

The (meth) acrylic acid esters are acrylic acid esters and / or methacrylic acid esters, and for example, R in CH ₂ CC (CH ₃ ) COOR is 1 to 18, preferably 1 to 4 And those in which R in CH ₂ CHCH—COOR is an alkyl group having 1 to 18 carbon atoms, preferably 4 to 8 carbon atoms.

When R in CH ₂ CHC (CH ₃ ) COOR is an alkyl group having 1 to 18 carbon atoms, examples thereof include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate and isobutyl methacrylate Preferably, methyl methacrylate and isobutyl methacrylate are mentioned.

When R in CH ₂ CHCH—COOR is an alkyl group having 1 to 18 carbon atoms, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like Preferably, butyl acrylate and 2-ethylhexyl acrylate are mentioned.

  The (meth) acrylic esters may be used alone or in combination of two or more.

  The content ratio of (meth) acrylic acid esters is, for example, 20% by mass or more, preferably 30% by mass or more, more preferably 40% by mass or more, further preferably, with respect to the total amount of the polymerization component (A). 45% by mass or more, for example, 90% by mass or less, preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less.

  If the content ratio of (meth) acrylic acid esters is the above-mentioned content ratio, the surface sizing agent obtained by the method for producing a surface sizing agent of the present invention can exhibit a more excellent size effect.

  The polymerization component (A) preferably contains styrene as its essential component, and one or more selected from the group consisting of methyl methacrylate, butyl acrylate, isobutyl methacrylate and 2-ethylhexyl acrylate. More preferably, styrene is essential, and two are selected from the group consisting of methyl methacrylate, butyl acrylate, isobutyl methacrylate, and 2-ethylhexyl acrylate. More preferably, combined use of styrene, methyl methacrylate and 2-ethylhexyl acrylate and combined use of styrene, isobutyl methacrylate and 2-ethylhexyl acrylate can be mentioned. Particularly preferred is a combination of styrene, methyl methacrylate and 2-ethylhexyl acrylate.

  When the (meth) acrylic acid ester contains methyl methacrylate, the content of methyl methacrylate is, for example, 5% by mass or more, preferably 10% by mass, with respect to the total amount of the polymerization component (A). % Or more, more preferably 12% by mass or more, for example, 25% by mass or less, preferably 20% by mass or less, more preferably 16% by mass or less.

  When the (meth) acrylic acid ester contains butyl acrylate, the content of butyl acrylate is, for example, 10% by mass or more, preferably 15% by mass, with respect to the total amount of the polymerization component (A). % Or more, more preferably 20% by mass or more, for example, 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less, further preferably 25% by mass or less.

  When the (meth) acrylic acid ester contains isobutyl methacrylate, the content ratio of isobutyl methacrylate is, for example, 5% by mass or more, preferably 10% by mass with respect to the total amount of the polymerization component (A). % Or more, more preferably 15% by mass or more, further preferably 20% by mass or more, for example, 40% by mass or less, preferably 30% by mass or less, more preferably 28% by mass or less.

  When the (meth) acrylic acid ester contains 2-ethylhexyl acrylate, the content ratio of 2-ethylhexyl acrylate is preferably, for example, 15% by mass or more, based on the total amount of the polymerization component (A). Is 20% by mass or more, more preferably 25% by mass or more, still more preferably 30% by mass or more, particularly preferably 33% by mass or more, for example, 40% by mass or less, preferably 38% by mass or less It is.

  The polymerization component (A) can further contain a hydrophilic group-containing monomer.

  Examples of hydrophilic group-containing monomers include carboxyl group-containing monomers, amino group-containing monomers, amide group-containing monomers, and heterocycle-containing monomers.

  As a carboxyl containing monomer, a monocarboxylic acid containing monomer, a dicarboxylic acid containing monomer, and an acid anhydride are mentioned, for example.

  As a monocarboxylic acid containing monomer, acrylic acid, methacrylic acid, crotonic acid etc. are mentioned, for example, Preferably, methacrylic acid is mentioned.

  Examples of the dicarboxylic acid-containing monomer include maleic acid, fumaric acid, itaconic acid, citraconic acid and the like.

  Examples of the acid anhydride include acid anhydrides of monocarboxylic acid-containing monomers and dicarboxylic acid-containing monomers.

  Examples of the amino group-containing monomer include 2- (dimethylamino) ethyl methacrylate and dimethylaminopropyl acrylamide and the like, and preferably 2- (dimethylamino) ethyl methacrylate.

  As an amide group containing monomer, N-vinyl formamide etc. are mentioned, for example.

  As a heterocycle containing monomer, N-vinyl pyrrolidone etc. are mentioned, for example.

  As a hydrophilic group containing monomer, Preferably, a carboxylic acid containing monomer, More preferably, a monocarboxylic acid containing monomer, More preferably, a methacrylic acid is mentioned.

  The hydrophilic group-containing monomer may be used alone or in combination of two or more.

  When the hydrophilic group-containing monomer is contained, the content ratio thereof is, for example, 1% by mass or more, preferably 2% by mass or more, and for example, 20% by mass or less with respect to the total amount of the polymerization component (A). Preferably, it is 10 mass% or less, More preferably, it is 8 mass% or less, More preferably, it is 4 mass% or less.

  If the content ratio of the hydrophilic group-containing monomer is the above content ratio, the surface sizing agent obtained by the method for producing a surface sizing agent of the present invention can exhibit a more excellent size effect.

  And in the manufacturing method of the surface sizing agent of this invention, the above-mentioned superposition | polymerization component (A) is emulsion-polymerized in the solution containing starches (B) and polyamino polyamide resin (C).

  As starches (B), raw material starch and modified starch are mentioned, Preferably, modified starch is mentioned.

  Raw material starches include corn starch, potato starch, tapioca starch and wheat starch.

  Modified starches are derived from the above-mentioned raw material starches, and cationic starch, oxidized starch, phosphoric acid modified starch, carboxymethylated starch, hydroxyethylated starch, carbamylethylated starch, dialdehyded starch, acetic acid modified starch, etc. Preferably, acetic acid modified starch derived from tapioca starch is mentioned.

  The method for obtaining the modified starch is not particularly limited, but in the case of obtaining an acetic acid-modified starch, for example, the raw material starch is dispersed in water, then the pH is adjusted with sodium hydroxide or the like, and then the enzyme is added, Heat and then add acetic acid.

  The starches (B) may be used alone or in combination of two or more.

  The content ratio of starches (B) is, for example, 15% by mass or more, preferably 20% by mass or more based on the total amount of the polymerization component (A), starches (B), and polyaminopolyamide resin (C). More preferably, it is 25% by mass or more, more preferably 30% by mass or more, and for example, 60% by mass or less, preferably 50% by mass or less, more preferably 45% by mass or less.

  The starches (B) are obtained, for example, as an aqueous solution or aqueous dispersion, and the solid content concentration is, for example, 5% by mass or more, preferably 10% by mass or more, and for example, 40% by mass or less, preferably And 30% by mass or less.

  Moreover, the viscosity (solid content concentration 25%, 25 ° C.) of the aqueous solution or aqueous dispersion of the starches (B) obtained is, for example, 5 mPa · s or more, preferably 10 mPa · s or more, more preferably 50 mPa · s. It is s or more, for example, 300 mPa · s or less, preferably 200 mPa · s or less, more preferably 100 mPa · s or less.

  The viscosity can be measured in accordance with JIS Z 8803.

  The polyamino polyamide resin (C) is not particularly limited, and can be obtained, for example, by the dehydration condensation reaction of a polyalkylene polyamine and a dicarboxylic acid and / or a derivative thereof.

  Examples of polyalkylene polyamines include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diaminodipropylamine (iminobispropylamine) and the like, with preference given to diethylenetriamine.

  These polyalkylene polyamines may be used alone or in combination of two or more.

  In addition, in this method, polyalkylene polyamine and monoalkylene diamine can be used in combination, if necessary.

  Examples of monoalkylene diamines include ethylene diamine and hexamethylene diamine.

  These monoalkylene diamines may be used alone or in combination of two or more.

  In addition, when using polyalkylene polyamine and monoalkylene diamine together, those content rates are suitably set according to the objective and a use.

  Examples of dicarboxylic acids and / or derivatives thereof include dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid, and Anhydrides of these dicarboxylic acids, and further, esterified products of dicarboxylic acids and the like can be mentioned, with preference given to dicarboxylic acids (non-derivatives), more preferably adipic acid.

  These dicarboxylic acids and / or their derivatives may be used alone or in combination of two or more.

  The content ratio of the polyalkylene polyamine and the dicarboxylic acid and / or the derivative thereof is, for example, 20 parts by mass or more, preferably 30 parts by mass or more, with respect to 100 parts by mass of the total amount thereof. For example, it is 80 parts by mass or less, preferably 60 parts by mass or less, more preferably 50 parts by mass or less. The dicarboxylic acid and / or the derivative thereof is, for example, 20 parts by mass or more, preferably 40 parts by mass or more, and for example, 80 parts by mass or less, preferably 60 parts by mass or less.

  If the content ratio of the polyalkylene polyamine and the dicarboxylic acid and / or the derivative thereof is in the above range, the surface sizing agent can be favorably dispersed, and a polyamino polyamide resin having a viscosity excellent in workability is obtained. Can.

  The reaction conditions for the polyalkylene polyamine and the dicarboxylic acid and / or the derivative thereof are, for example, 110 ° C. or more, preferably 140 ° C. or more, and for example, 250 ° C. or less, preferably 200 ° C. It is below. The reaction time is, for example, 0.5 hours or more, preferably 2 hours or more, and for example, 12 hours or less, preferably 6 hours or less. Thereby, a polyamino polyamide resin can be obtained.

  The polyamino polyamide resin is obtained, for example, as an aqueous solution or aqueous dispersion, and the solid content concentration is, for example, 5% by mass or more, preferably 10% by mass or more, and for example, 40% by mass or less, preferably 30 It is less than mass%.

  The viscosity (solid content concentration 28%, 25 ° C.) of the aqueous solution or aqueous dispersion of the polyaminopolyamide resin is, for example, 50 mPa · s or more, preferably 100 mPa · s or more, more preferably 200 mPa · s or more For example, it is 500 mPa · s or less, preferably 400 mPa · s or less, more preferably 350 mPa · s or less.

  The number average molecular weight (calculated value) of the resulting polyaminopolyamide resin is, for example, 200 or more, preferably 500 or more, and for example, 10000 or less, preferably 5000 or less.

  In addition, the number average molecular weight (calculated value) of polyamino polyamide resin can be calculated from the preparation amount of a raw material.

  Alternatively, the primary amino group at the molecular end of the polyaminopolyamide resin may be reacted with an end capping agent to cap the molecular end of the polyaminopolyamide resin.

  Examples of the end capping agent include monovalent aliphatic carboxylic acids, monovalent aromatic carboxylic acids, and monovalent aromatic aliphatic carboxylic acids.

  Examples of monovalent aliphatic carboxylic acids include aliphatic carboxylic acids having a hydrocarbon group having 6 to 22 carbon atoms, and more specifically, lauric acid (the carbon number of the hydrocarbon group: 11 And stearic acid (carbon number of hydrocarbon group: 17), oleic acid (carbon number of hydrocarbon group: 17), behenic acid (carbon number of hydrocarbon group: 21), etc., preferably stearic acid Can be mentioned.

  Examples of monovalent aromatic carboxylic acids include aromatic carboxylic acids having an aromatic ring having 6 to 20 carbon atoms, and more specifically, benzoic acid (aromatic carbon number: 6), naphthalene Aromatic monocarboxylic acids such as carboxylic acids (the carbon number of the aromatic ring: 10) and anthracene carboxylic acids (the carbon number of the aromatic ring: 14) can be mentioned, with preference given to benzoic acid.

  As a monovalent aromatic aliphatic carboxylic acid, for example, a monovalent aromatic fat having an aromatic ring having 6 to 20 carbon atoms and an aliphatic hydrocarbon group having 1 to 20 carbon atoms bonded to the aromatic ring Group carboxylic acid, more specifically phenylacetic acid (carbon number of aromatic ring: 6, carbon number of aliphatic hydrocarbon group: 1), phenylpropionic acid (carbon number of aromatic ring: 6, aliphatic) Aromatic aliphatic monocarboxylic acids such as carbon number of hydrocarbon group: 2), phenyl decanoic acid (carbon number of aromatic ring: 6, carbon number of aliphatic hydrocarbon group: 10) and the like can be mentioned.

  The end capping agent may be used alone or in combination of two or more, and preferably used in combination.

  When the end capping agent is used alone, preferably, the use of a monovalent aliphatic carboxylic acid alone is mentioned.

  When an end capping agent is used in combination, preferably, a combination of a monovalent aliphatic carboxylic acid and a monovalent aromatic carboxylic acid is mentioned.

  By containing these, it is possible to secure excellent dispersibility and to improve storage stability.

  When the end capping agent contains a monovalent aliphatic carboxylic acid and a monovalent aromatic carboxylic acid, the monovalent aliphatic carboxylic acid is used per 100 parts by mass of the monovalent aromatic carboxylic acid. The content of the group carboxylic acid is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 100 parts by mass or more, still more preferably 200 parts by mass or more, for example, 2000 parts by mass or less Preferably, it is 1000 parts by mass or less, more preferably 600 parts by mass or less.

  If the content ratio of the monovalent aliphatic carboxylic acid is in the above range, better storage stability can be secured.

  The content ratio of the end capping agent is, for example, 1.0 parts by mass or more, preferably 2.0 parts by mass or more, more preferably 5.0 parts by mass with respect to 100 parts by mass of the polyalkylene polyamine. Or more, for example, 60 parts by mass or less, preferably 40 parts by mass or less, and more preferably 30 parts by mass or less.

  The reaction conditions for the polyamino polyamide resin and the end capping agent are the same as the reaction conditions for the polyalkylene polyamine and the dicarboxylic acid and / or the derivative thereof described above. This gives a polyaminopolyamide resin with molecular end capping.

  The polyamino polyamide resin having a molecular end capped is obtained, for example, as an aqueous solution or aqueous dispersion, and the solid content concentration is, for example, 5% by mass or more, preferably 10% by mass or more, for example, 40% by mass Below, Preferably, it is 30 mass% or less.

  Further, the viscosity (solid content concentration 28%, 25 ° C.) of the aqueous solution or aqueous dispersion of the polyaminopolyamide resin whose molecular end is capped is, for example, 50 mPa · s or more, preferably 100 mPa · s or more, more preferably The viscosity is 200 mPa · s or more, for example, 500 mPa · s or less, preferably 400 mPa · s or less, more preferably 350 mPa · s or less.

  When the molecular end of the polyaminopolyamide resin is capped with an end capping agent, the surface sizing agent obtained by the method for producing a surface sizing agent of the present invention can exhibit a more excellent size effect.

  In addition, the end-end capping agent may be compounded and reacted simultaneously with the polyalkylene polyamine, dicarboxylic acid and / or its derivative at the time of synthesis of the polyamino polyamide resin.

  Also, polyaminopolyamide resin (including molecularly end-capped polyaminopolyamide resin, the same applies hereinafter) can be subjected to addition reaction with epichlorohydrin to be modified.

  The content ratio of the polyaminopolyamide resin to the epichlorohydrin is, for example, 50 parts by mass or more, preferably 80 parts by mass or more, with respect to 100 parts by mass of the polyalkylene polyamine. It is 200 parts by mass or less, preferably 140 parts by mass or less.

  The reaction conditions for the polyamino polyamide resin and epichlorohydrin are, for example, a reaction temperature of 30 ° C. or more, preferably 40 ° C. or more, and for example, 80 ° C. or less, preferably 70 ° C. or less. The reaction time is, for example, 0.5 hours or more, preferably 1.0 hours or more, and for example, 10 hours or less, preferably 6 hours or less. This makes it possible to obtain a polyaminopolyamide-epichlorohydrin resin in which the polyaminopolyamide resin is modified with epichlorohydrin.

  In this method, if necessary, the polyaminopolyamide-epichlorohydrin resin can be heated to cause a crosslinking reaction (crosslinking reaction of epichlorohydrin).

  The reaction conditions for the crosslinking reaction are, for example, a reaction temperature of 40 ° C. or more, preferably 50 ° C. or more, and for example, 90 ° C. or less, preferably 80 ° C. or less. The reaction time is, for example, 0.5 hours or more, preferably 1 hour or more, and for example, 10 hours or less, preferably 6 hours or less.

  Further, in the above crosslinking reaction, a crosslinking agent can be blended, if necessary.

  Examples of the crosslinking agent include ethylene glycol diglycidyl ether, 1,6-hexanediol glycidyl ether, bisphenol A diglycidyl ether, toluene diisocyanate, hexamethylene diisocyanate and the like.

  These crosslinking agents may be used alone or in combination of two or more.

  The content ratio of the crosslinking agent is appropriately set depending on the purpose and application.

  By cross-linking in this manner, the size effect can be expressed more efficiently.

  In addition, in this method, the quaternary cation density is improved, whereby the surface sizing agent is fixed to the pulp fiber without depending on the papermaking pH, and it is contained in the polyaminopolyamide-epichlorohydrin resin if necessary. The tertiary amino group to be treated can also be quaternized.

  In the quaternization treatment, for example, together with the above-mentioned epichlorohydrin, a quaternizing agent such as 3-chloro-2-hydroxypropyltrimethylammonium chloride, glycidyltrimethylammonium chloride and the like is added, and the reaction is performed under the above conditions.

  In addition, in this method, the pH of the reaction solution can be adjusted to about 2 to 6 by adding an acid as necessary. The acid is not particularly limited, and examples thereof include inorganic acids such as sulfuric acid and hydrochloric acid, and organic acids such as formic acid and acetic acid.

  In such a method, the polyaminopolyamide-epichlorohydrin resin is obtained, for example, as an aqueous solution or aqueous dispersion, and its solid content concentration is, for example, 5% by mass or more, preferably 10% by mass or more, For example, it is 40% by mass or less, preferably 30% by mass or less.

  The viscosity (solid content concentration 28%, 25 ° C.) of the aqueous solution or aqueous dispersion of the polyaminopolyamide-epichlorohydrin resin to be obtained is, for example, 20 mPa · s or more, preferably 80 mPa · s or more. And 400 mPa · s or less, preferably 300 mPa · s or less.

  If the viscosity is in the above range, excellent dispersibility can be obtained, and gelation can be suppressed.

  When the polyaminopolyamide resin is modified with epichlorohydrin, the surface sizing agent obtained by the method for producing a surface sizing agent of the present invention can exhibit a more excellent size effect.

  In addition, when making the polyamino polyamide resin in which the molecular terminal is capped be added to epichlorohydrin and subjecting it to denature, the content ratio of the polyamino polyamide resin in which the molecular terminal is capped and epichlorohydrin is polyalkylene. The amount of epichlorohydrin is, for example, 50 parts by mass or more, preferably 80 parts by mass or more, and for example, 200 parts by mass or less, preferably 140 parts by mass or less with respect to 100 parts by mass of the polyamine.

  When the molecularly end-capped polyaminopolyamide resin is modified with epichlorohydrin, the surface sizing agent obtained by the method for producing a surface sizing agent of the present invention exhibits a more excellent size effect Can.

  The content ratio of the polyaminopolyamide resin (C) is 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass, based on the total amount of the starches (B) and the polyaminopolyamide resin (C). % Or more, particularly preferably 20% by mass or more, 50% by mass or less, preferably 45% by mass or less, more preferably 40% by mass or less, particularly preferably 30% by mass or less It is.

  If the content rate of polyamino polyamide resin (C) is the above-mentioned content rate, the surface sizing agent obtained by the manufacturing method of the surface sizing agent of the present invention can express a more excellent size effect.

  On the other hand, when the content of the polyaminopolyamide resin (C) exceeds the above upper limit, the particles of the surface sizing agent obtained by the method of producing a surface sizing agent of the present invention aggregate and exhibit an excellent sizing effect. I can not do it. Moreover, when the content rate of polyamino polyamide resin (C) is less than the said lower limit, the particle diameter will become large and it can not express the outstanding size effect.

  In addition, the content ratio of the polyaminopolyamide resin (C) is, for example, 1% by mass or more, preferably 5% of the total amount of the polymerization component (A), the starches (B) and the polyaminopolyamide resin (C). % By mass or more, more preferably 10% by mass or more, and for example, 25% by mass or less, preferably 20% by mass or less, more preferably 15% by mass or less, particularly preferably 12% by mass or less is there.

  In addition, the content ratio of the starches (B) and the polyaminopolyamide resin (C) is, for example, 20% by mass or more based on the total amount of the starches (B), the polyaminopolyamide resin (C) and the polymerization component (A) Preferably, it is 30% by mass or more, more preferably 35% by mass or more, further preferably 40% by mass or more, for example, 70% by mass or less, preferably 60% by mass or less, more preferably 55% by mass The content is more preferably 50% by mass or less.

  If the content ratio of the starches (B) and the polyaminopolyamide resin (C) is the above content ratio, the surface sizing agent obtained by the method for producing a surface sizing agent of the present invention exhibits a more excellent size effect can do.

  In addition, the content ratio of the polymerization component (A) is, for example, 30% by mass or more, preferably 40 mass%, based on the total amount of the polymerization component (A), the starches (B), and the polyaminopolyamide resin (C). % Or more, more preferably 45% by mass or more, particularly preferably 50% by mass or more, for example, 80% by mass or less, preferably 70% by mass or less, more preferably 60% by mass or less.

  Then, for emulsion polymerization, a solution (aqueous solution) containing starches (B) and polyaminopolyamide resin (C) is prepared.

  When the starches (B) and the polyaminopolyamide resin (C) are each prepared as a solution (aqueous solution), they are blended.

  Moreover, when starches (B) and polyamino polyamide resin (C) are not prepared as a solution (aqueous solution), they are diluted with a solvent (water) and are compounded or compounded, and a solvent (water) Dilute with).

  And in order to carry out emulsion polymerization, the polymerization component (A) is blended in the above-mentioned solution (aqueous solution). The polymerization component (A) may be blended when preparing a solution (aqueous solution) containing the starches (B) and the polyaminopolyamide resin (C).

  In emulsion polymerization, a polymerization initiator is added to a solution (aqueous solution).

  Examples of the polymerization initiator include peroxide-based polymerization initiators, heavy metal salts, and azo-based initiators.

  As a peroxide type polymerization initiator, hydrogen peroxide, an inorganic peroxide, an organic peroxide is mentioned, for example.

  As an inorganic peroxide, ammonium persulfate, potassium persulfate etc. are mentioned, for example.

  Examples of the organic peroxide include benzoyl peroxide, dicumyl peroxide, lauryl peroxide and the like, and preferably benzoyl peroxide.

  Examples of heavy metal salts include sulfates such as cerium, manganese, iron and copper, and the like, with preference given to iron sulfate.

  Examples of the azo initiator include azobismethylbutyronitrile, dimethylazobisisobutyrate, azobisdimethylvaleronitrile, azobisisobutyronitrile and the like.

  The polymerization initiator may be used alone or in combination of two or more. Preferably, hydrogen peroxide is added at the start of the reaction, and an organic peroxide is added during the reaction.

  The addition ratio of the polymerization initiator is, for example, 0.1 parts by mass or more, preferably 1 part by mass or more, more preferably 5 parts by mass or more, with respect to 100 parts by mass of the polymerization component (A). For example, it is 20 parts by mass or less, preferably 10 parts by mass or less.

  Furthermore, in emulsion polymerization, a chain transfer agent may be added to the solution (aqueous solution).

  The chain transfer agent is used to control the weight average molecular weight of the polymerization component (A).

  Chain transfer agents include oil soluble chain transfer agents, water soluble chain transfer agents.

  Examples of oil-soluble chain transfer agents include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, mercapto propionic acid dodecyl ester, cumene, carbon tetrachloride, α-methylstyrene dimer, terpinolene etc It can be mentioned.

  Examples of water-soluble chain transfer agents include mercaptoethanol, thioglycolic acid and salts thereof.

  The chain transfer agent may be used alone or in combination of two or more.

  The chain transfer agent is appropriately selected according to the composition of the polymerization component (A), and the addition ratio thereof is appropriately determined such that the polymerization component (A) having a desired weight average molecular weight can be obtained.

  Specifically, the emulsion polymerization is carried out in a reaction vessel equipped with a suitable heating device and a stirrer, polymerization component (A), starches (B), polyaminopolyamide resin (C), polymerization initiator, water, if necessary. Then, a chain transfer agent and an additive are added, and the mixture is heated to a predetermined temperature and reacted under stirring.

  The reaction conditions in the emulsion polymerization are, for example, a reaction temperature of 60 ° C. or more, preferably 70 ° C. or more, and for example, 130 ° C. or less, preferably 120 ° C. or less. The reaction time is, for example, 0.5 hours or more, preferably 2 hours or more, and for example, 12 hours or less, preferably 6 hours or less. Thereby, the surface sizing agent is obtained as an emulsion.

  The average particle size of the obtained emulsion is, for example, 30 nm or more, preferably 40 nm or more, more preferably 50 nm or more, and for example, 500 nm or less, preferably 250 nm or less, more preferably 200 nm or less, more preferably 100 nm or less, particularly preferably 90 nm or less, most preferably 60 nm or less.

  The average particle size can be measured by a particle size distribution analyzer or the like.

  If the average particle diameter is in the above range, an excellent size effect can be realized.

  Further, the viscosity (25 ° C.) of the surface sizing agent to be obtained is, for example, 5 mPa · s or more, preferably 10 mPa · s or more, more preferably 15 mPa · s or more, for example, 25 mPa · s or less, preferably Is 20 mPa · s or less, more preferably 18 mPa · s or less.

  If the viscosity is in the above range, excellent dispersibility can be obtained, and gelation can be suppressed.

  In addition, the surface sizing agent obtained is, if necessary, diluted with water, and the solid content concentration is, for example, 20% by mass or more, preferably 25% by mass or more, and for example, 40% by mass or less, preferably The pH is adjusted to, for example, 1.5 or more, preferably 2.0 or more, and for example, 4.0 or less, preferably 3.5 or less.

  During or after polymerization, a water-soluble aluminum compound may be further added as needed.

  As the water-soluble aluminum compound, various known compounds can be used, and aluminum sulfate, aluminum chloride, basic aluminum sulfate, polyaluminum chloride, basic aluminum chloride, aluminum sulfate silicate, etc. may be mentioned, preferably, polyaluminum chloride It can be mentioned.

  The addition ratio of the water-soluble aluminum compound is, for example, 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more with respect to 100 parts by mass of the polymerization component (A). , 25 parts by mass or less, preferably 20 parts by mass or less.

  At the time of polymerization or thereafter, various additives may be further added as required.

  Additives include, for example, assistants such as antifoaming agents, preservatives, chelating agents, lubricants, anti-slip agents, rust inhibitors, anti-UV agents, anti-fading agents, fluorescent brighteners, viscosity stabilizers, alkaline substances, etc. And other surface sizing agents, surface paper strengthening agents and the like.

  The additives may be used alone or in combination of two or more.

  The surface sizing agent of the present invention is obtained by the method described above. The surface sizing agent obtained in this way exhibits a better size effect.

  The paper of the invention is obtained using the surface sizing agents described above.

  It does not restrict | limit especially as a manufacturing method of paper, A well-known method is employable.

  More specifically, for example, a paper treated with a surface sizing agent is obtained by applying and drying the above-mentioned surface sizing agent on a paper obtained by papermaking from a pulp slurry (untreated paper). it can. Also, for example, paper can be obtained by adding the above-described surface sizing agent to a pulp slurry and making a paper.

  And since the paper of this invention obtained by doing in this way is obtained using said surface sizing agent, it is excellent in suppression of an ink bleed.

  Hereinafter, the present invention will be described more specifically by showing Examples and Comparative Examples. The present invention is not limited to the examples and comparative examples. In addition, specific numerical values such as mixing ratios (content ratios), physical property values, parameters, etc. used in the following description are the mixing ratios corresponding to those described in the above-mentioned “embodiments for carrying out the invention” Substitutes the upper limit (numerical value defined as "below", "less than") or lower limit (numerical value defined as "above", "excess"), etc. of the corresponding description such as content ratio), physical property value, and parameters be able to. In addition, "part" and "%" are mass references | standards unless there is particular mention.

  In addition, the symbol of the component used for a following example and a comparative example is shown below.

St: Styrene MMA: methyl methacrylate nBA: butyl acrylate iBMA: isobutyl methacrylate 2 EHA: 2-ethylhexyl acrylate MAA: methacrylic acid DM: 2- (dimethylamino) ethyl methacrylate Alum: polyaluminum chloride 1. Preparation of sizing agent 1) Preparation of acetic acid-modified starch 140 parts of tapioca starch and 418 parts of water were dispersed in a four-necked flask equipped with a stirrer, thermometer, reflux condenser, water divider and nitrogen gas inlet pipe After that, the pH was adjusted to around 6 with 1% sodium hydroxide. Thereafter, 0.035 parts of an enzyme (klytase SD8: manufactured by Amano Enzyme Inc.) was added, and the temperature was raised to 90 ° C. and maintained for 1 hour. After 1 hour, 3.9 parts of acetic acid was added and cooled to obtain an acetic acid-modified starch solution having a solid content of 24.9% and a viscosity of 210 mPa · s (25 ° C.).
2) Preparation of Polyamide Polyamino Resin Preparation Example 1
88 parts of diethyleneamine, 112 parts of adipic acid, 9 parts of stearic acid and 2 parts of benzoic acid are placed in a four-necked flask equipped with a stirrer, thermometer, reflux condenser, water divider and nitrogen gas inlet pipe. After making the inside into a nitrogen atmosphere, the temperature is gradually raised, dehydration condensation reaction is performed at 150 to 160 ° C. for 3 hours, and dilution with warm water is performed to obtain a 36% aqueous solution of polyaminopolyamide resin. Next, 94 parts of epichlorohydrin were added dropwise over 30 minutes at 40 ° C. while stirring, and left for 30 minutes. Thereafter, warm water is added to dilute the aqueous solution of polyaminopolyamide resin to 31%, and then crosslinking reaction is carried out at 60 ° C. for 3 hours, and when the viscosity becomes 100 mPa · s (60 ° C.) or more, pH 3 or less with 10% sulfuric acid The solution was adjusted to obtain a polyamino polyamide-epichlorohydrin resin aqueous solution having a solid content concentration of 28.6% and a viscosity of 100 mPa · s (25 ° C.).

Production Example 2
Polyaminopolyamide having a solid concentration of 28.3% and a viscosity of 170 mPa · s (25 ° C.) in the same manner as in Production Example 1 except that 9 parts of stearic acid and 2 parts of benzoic acid were changed to 14 parts of stearic acid. An epichlorohydrin resin aqueous solution was obtained.

Production Example 3
Solid content concentration 28.8 in the same manner as in Production Example 1 except that 88 parts of diethyleneamine, 112 parts of adipic acid, 9 parts of stearic acid and 2 parts of benzoic acid are changed to 88 parts of diethylamine and 119 parts of adipic acid. % And a viscosity of 210 mPa · s (25 ° C.) were obtained as an aqueous solution of polyaminopolyamide-epichlorohydrin resin.

Production Example 4
An aqueous solution of polyaminopolyamide resin having a solid concentration of 28.0% and a viscosity of 320 mPa · s (25 ° C.) was obtained by the same method as in Production Example 3 except that epichlorohydrin was not blended.
3) Synthesis of Surface Sizing Agent The acetic acid-modified starch solution prepared as described above was diluted to 20% with water, and the polyaminopolyamide-epichlorohydrin resin aqueous solution prepared as described above, and prepared as described above The polyaminopolyamide resin aqueous solution was diluted to 21% with water.

Example 1
In a 1-liter four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen inlet tube, 591 parts of a 20% acetic acid-modified starch solution and 21% polyamide polyaminoepichlorohydrin resin solution 141 of Production Example 1 After adding 16.2 parts of 2% ferric sulfate (manufactured by Wako Pure Chemical Industries, Ltd.) and thoroughly stirring oxygen in a nitrogen stream while removing oxygen from the reaction vessel, the temperature was raised to 85.degree. While keeping the temperature constant, separately take 147 parts (88 parts of styrene, 15 parts of isobutyl methacrylate, 44 parts of 2-ethylhexyl acrylate) and 70.9 parts of a 10% aqueous solution of hydrogen peroxide separately for 3 hours Thirty minutes after the addition, 0.8 parts of organic peroxide (benzoyl peroxide) was added, followed by aging for one hour. Thereafter, it was cooled to room temperature and diluted with water to obtain a surface sizing agent having a solid content of 30.0%, pH 2.8, viscosity 15 mPa · s, and particle diameter 55 nm.

Examples 2 to 19 and Comparative Examples 1 to 3
The surface sizing agents of Examples 2 to 19 and Comparative Examples 1 to 3 were prepared in the same manner as in Example 1 except that the composition of each component was changed according to the description in Table 1. The physical property values of Examples 1 to 19 and Comparative Examples 1 to 3 are shown in Table 2.

In Example 13, 153 parts of 30% polyaluminum chloride was added to 847 parts of the surface sizing agent having a solid content concentration of 30% obtained in Example 12.
2. Evaluation With respect to the surface sizing agents obtained in the above-mentioned Examples and Comparative Examples, the size properties (Stickt's size and 2-minute Cobb water absorption) were evaluated by the following methods. The results are shown in Table 2.
1) Measurement of Squecht Size Measurement Dilute oxidized starch ("MS-3800" manufactured by Japan Food Processing Co., Ltd.) with distilled water to a concentration of 10% by mass, gelatinize at 95 ° C, hardness 500 ppm (as CaCO ₃ ) The mixture was diluted to 5% by mass of oxidized starch with synthetic hard water. The surface sizing agent was added to the oxidized starch solution to adjust the coating liquid to a solid content of 0.2% by mass.

The coating solution obtained above is kept warm at 50 ° C. on a neutral wood-free paper (basis weight 70 g / m ² , Squeech size 0 sec, pH 7.6) to which no internal sizing agent is added, and the size is It coated by a press and obtained coated paper. Then, after conditioning the obtained coated paper in a constant temperature and humidity environment (22 ° C., relative humidity 50%) for 12 hours, the size property was evaluated by measuring the degree of sizing (seconds).

The degree of size of the dead person (seconds) was measured according to JIS P 8122.
2) Cobb water absorption measurement Commercial corn starch is diluted with distilled water to a concentration of 10% by mass, 0.5% by mass of ammonium persulfate is added to starch solid content, and then gelatinized at 95 ° C. It was diluted to 8% by mass of starch with synthetic hard water having a hardness of 500 ppm (as CaCO ₃ ). The surface sizing agent was added to the corn starch prepared above so as to have a solid content of 0.1% by mass to adjust the coating liquid.

Heat the coating solution obtained above at 60 ° C. on a liner base paper (basis weight 170 g / m ² , 2 min Cobb water absorption 210 g / m ² , paper surface pH 7.2) to which no internal sizing agent is added, The coated paper was obtained by coating with a size press. Then, after conditioning the obtained coated paper in a constant temperature and humidity environment (22 ° C., relative humidity 50%) for 12 hours, the size property was evaluated by measuring the Cobb water absorption (g / m ² ). .

Cobb water absorption (g / m ² ) was measured according to JIS P 8140.

  The method of producing a surface sizing agent of the present invention is utilized in the papermaking industry.

  Further, as the paper to which the surface sizing agent of the present invention can be applied, various kinds of paper such as paperboard, newsprint paper, writing paper, wallpaper, PPC paper, ink jet paper, printing paper, paperboard such as liner and core etc. may be mentioned. .

Claims (6)

A method for producing a surface sizing agent obtained by emulsion polymerization of a polymerization component (A) containing styrenes and (meth) acrylic acid esters,
The above polymerization component (A) is emulsion-polymerized in a solution containing starches (B) and a polyaminopolyamide resin (C),
With respect to the total amount of the starches (B) and the polyaminopolyamide resin (C),
The method for producing a surface sizing agent, wherein the content of the polyaminopolyamide resin (C) is 5% by mass to 50% by mass. With respect to the total amount of the polymerization component (A), the starches (B) and the polyaminopolyamide resin (C),
The method for producing a surface sizing agent according to claim 1, wherein a content ratio of the starches (B) and the polyaminopolyamide resin (C) is 30% by mass or more and 60% by mass or less. With respect to the total amount of the polymerization component (A),
The content ratio of the styrenes is 20% by mass or more and 70% by mass or less,
The method for producing a surface sizing agent according to claim 1, wherein a content ratio of the (meth) acrylic acid ester is 30% by mass or more and 80% by mass or less. The polymerization component (A) further contains a hydrophilic group-containing monomer,
With respect to the total amount of the polymerization component (A),
The method for producing a surface sizing agent according to any one of claims 1 to 3, wherein the content ratio of the hydrophilic group-containing monomer is more than 0% by mass and 10% by mass or less.   The method for producing a surface sizing agent according to any one of claims 1 to 4, wherein the molecular end of the polyamino polyamide resin (C) is capped by an end capping agent.   The method for producing a surface sizing agent according to any one of claims 1 to 5, wherein the polyaminopolyamide resin (C) is modified with epichlorohydrin.