JP4536454B2 - Pharmaceutical particles for papermaking - Google Patents

Description

  The present invention relates to papermaking drug particles and a method for producing the same.

  Conventionally, in the manufacturing process of paper products, various papermaking chemicals are added for the purpose of imparting functions such as glossiness and water resistance, improving quality such as size and rigidity, and improving productivity. Some of these papermaking chemicals have high or low solubility in water.

  In the case of a drug with high water solubility, it can be added as an aqueous solution before the paper making process, applied to the surface after paper making, or penetrated to express the desired function. In the case of oil-based papermaking chemicals having low solubility, uniform blending and application are difficult unless they are once dissolved in a solvent, and problems such as solvent recovery in the drying process also occur.

The use of oily papermaking chemicals with low water solubility in the papermaking process involves technical difficulties and process disadvantages, while oily papermaking chemicals have low water solubility. Therefore, it has been used as a paper quality improver. (Patent Documents 1 and 2)
In the case of using an oily papermaking chemical in a papermaking process, a method of adjusting the oil droplet diameter by emulsification and adding it as an aqueous emulsion is known. For example, in the case of an oil-based paper-making chemical that is solid at room temperature, in order to adjust the oil droplet diameter, the emulsion is first heated to the melting point or higher to obtain an emulsion. However, in the actual papermaking scene, a large amount of water is used and it is usually operated at room temperature, so it is cooled in one of the processes, and the state of the drug changes from liquid to solid and becomes unstable. Cheap. For this reason, it becomes an aggregate of 300 μm or more in the process of cooling, which may cause sedimentation and floating in the drug solution, causing production problems and quality problems such as oil spots. There is. Therefore, in such a case, it is necessary to cool while suppressing agglomeration by a method such as rapid cooling, which further increases the equipment load.
Japanese Patent No. 2971447 WO98 / 03730

  In the papermaking process, when adding an oily papermaking chemical that has low solubility in water and is difficult to handle as an aqueous solution, an addition method that requires a solvent requires its recovery equipment, and a method that requires emulsification at the time of addition. Each papermaking equipment requires an emulsifying equipment, and when it is stored as an aqueous emulsion, there is a problem that a huge storage space is required due to the low content of the active agent.

  The present invention relates to a papermaking drug particle that can be used simply by adding / stirring to cold water when adding an oily papermaking drug that has low solubility in water and is difficult to handle as an aqueous solution in the papermaking process, and a method for producing the same It is an issue to provide.

  As a means for solving the problems, the present invention provides a papermaking drug particle in which an oily papermaking drug is dispersed as oil droplets in a water-soluble solid matrix.

  As another means for solving the problem, the present invention includes a step of dissolving a water-soluble solid matrix forming agent in water having a temperature equal to or higher than the melting point of the oil-based papermaking agent, and then an oil-based papermaking agent and, if necessary, an emulsifying substance. There is provided a method for producing a papermaking drug particle comprising the steps of adding and emulsifying an oily papermaking drug to obtain an emulsion, and drying the emulsion at a temperature equal to or higher than the melting point of the oily papermaking drug.

  The emulsified substance in the present invention means a substance having an action of emulsifying an oil-based papermaking chemical in water.

  Although the papermaking drug particles of the present invention contain an oily papermaking drug having low solubility in water, operations such as heating and quenching are unnecessary because of good dispersibility in water at room temperature. It is. Further, when the papermaking drug particles of the present invention are applied to the papermaking process, the effect of the drug can be obtained.

<Pharmaceutical particles for papermaking>
The papermaking drug particles of the present invention are those in which an oily papermaking drug is dispersed as oil droplets in a water-soluble solid matrix, and may contain an emulsified substance as necessary.

  The water-soluble solid matrix encloses oil droplets (oil-based paper-making chemicals) and also forms a film of paper-making chemical particles. Oil droplets (oil-based papermaking chemicals) are encapsulated in a water-soluble solid matrix, but some of them may be exposed to the film. The oil droplets (oil-based papermaking chemicals) are preferably present in a fixed state so as not to move in the water-soluble solid matrix. In addition, the thing which a hollow part exists in particle | grains (for example, particle center vicinity) by the drying process at the time of manufacture is also contained.

  The shape of the paper-making drug particles is not particularly limited, and may be indefinite or spherical, and may be formed into a desired shape.

  The oil droplet diameter is preferably 0.1 to 50 μm, more preferably 0.1 to 30 μm, and still more preferably 0.5 to 10 μm on a volume basis average. The volume standard average was measured by a light scattering method using LA-910 manufactured by Horiba.

  By making the oil droplet diameter 50 μm or less, the dispersibility when added to the papermaking process is enhanced, and there is no large lump on the pulp surface, and oil spots and performance variations do not occur. By setting the oil droplet diameter to 0.1 μm or more, the amount of the emulsified substance used can be reduced, and the emulsion can be emulsified with a general-purpose emulsifier, which facilitates production.

  Also, large oil droplets of 300 μm or more are desirably as few as possible because they directly cause oil spots. In the oil droplets, 1% by volume or less is preferable, and 0.1% by volume or less is more preferable.

  The oil droplet size is the same as the particle size of the oil droplet in the emulsion at the time of manufacture and the particle size at the time of redispersion when used in the papermaking process, so that the emulsion and the emulsified state at the time of drying are stable. And the encapsulation state (the state in which oil droplets (oil-based papermaking chemicals) are dispersed and included in the water-soluble solid matrix) indicates that good particles are obtained, and the stability of performance and This is advantageous in terms of productivity during drying. However, if the average particle diameter is in the range of 50 μm or less, there is no practical problem even if some aggregates are seen in the redissolved material due to insufficient stability during drying, and no special equipment is required in the papermaking scene. The effect as a papermaking chemical that can be used simply by dispersing in cold water is exhibited.

  The average particle size of the papermaking drug particles is preferably 10 to 3000 μm, more preferably 50 to 1000 μm, and still more preferably 100 to 500 μm. An average particle size of 10 μm or more is preferable because the ratio of oil droplets exposed on the particle surface is small and the cold water dispersibility is good. In addition, an average particle size of 3000 μm or less is preferable because general-purpose drying equipment can be used, and thus productivity is good. Furthermore, when spray drying is used as the drying method, it is desirable that the thickness be 500 μm or less due to equipment limitations. In addition, the measuring method of this average particle diameter is the same as the measuring method of the average particle diameter of the papermaking drug particle in the Example mentioned later.

  Hereinafter, each component constituting the papermaking drug particles will be described.

(Water-soluble solid matrix)
The components that form a water-soluble solid matrix (water-soluble solid matrix forming agent) include glucose, fructose, lactose, maltose, sucrose and other water-soluble saccharides, dextrin, maltodextrin, cyclodextrin and other hydrolyzed starch, octenyl succinate starch Modified starch such as gelatin, agar, sodium carboxymethylcellulose, polyvinyl alcohol and the like. These may be subjected to processing such as terminal modification for the purpose of suppressing deterioration and moisture absorption during storage of the papermaking drug particles.

  Among these, starches such as maltodextrin, cyclodextrin, and octenyl succinate starch are preferable because an aqueous solid matrix having a dense structure can be obtained. Here, the dense structure means a structure in which voids are present in the aqueous solid matrix but the void diameter is small (fine voids).

(Oil-based papermaking chemicals)
The oil-based papermaking chemicals are not particularly limited as long as they have a low solubility in water and are difficult to be dissolved in water and introduced into the papermaking process, and are therefore preferably used as bulking agents. The “bulky agent” in the present invention means a component that acts to increase the volume of the paper (reduce the density), and specifically, the “bulk improvement rate” shown in the examples. It can be enlarged.

  The oil-based papermaking chemical is preferably one that does not become uniform and transparent when it is kept at 20 ° C. after adding and stirring to water to a concentration of 1% by mass (may be heated to 100 ° C. or lower during the course). .

  The oily papermaking agent is preferably one or more compounds selected from the group consisting of the following (i) to (viii), and is preferably a solid at 20 ° C. from the viewpoint of size performance. The solid means one that is in a state below the melting point, or one that has no fluidity or is in a state in which the fluidity is remarkably reduced even when the melting point is exceeded.

(i) Organopolysiloxane compound
Methyl polysiloxane having a viscosity at 25 ° C. of 10 to 1,000,000 mPa · s, a polyoxyethylene methylpolysiloxane copolymer having an HLB of 1 to 14 by the Griffin method, and a poly (oxyethylene oxypropylene) methyl having an HLB of 1 to 14 Examples include polysiloxane copolymers.

(ii) Amine compounds, (iii) Aminate compounds, (iv) Quaternary ammonium compounds, (v) Imidazole compounds The compounds represented by the following general formulas (b) to (j) are exemplified. Aminates include those that are ionized and those that are not ionized.

[Where,
Y ₁ , Y ₂ : the same or different from each other, hydrogen atom, R ₄ , R ₆ CO-,-(AO) _n -COR ₃ or-(AO) _n -H
AO: C2-C4 alkylene oxide
Y ₃ : hydrogen atom or -COR ₆

R _{1 is} an alkyl group having 8 to 35 carbon atoms, an alkenyl group, or a β-hydroxyalkyl group.
R ₂ , R ₃ , R ₆ , R ₉ : an alkyl group, alkenyl group or β-hydroxyalkyl group having 7 to 35 carbon atoms
_{R 4,} R _5: a hydrogen atom or an alkyl group having 1 to 3 carbon atoms
_{R 7,} R _8: an alkyl group having 1 to 3 carbon atoms
R ₁₀ : hydrogen atom or R ₉
n: number of 1 to 20 and average number of moles
X ⁻ : anion)
(vi) Hydrocarbon compounds Wax, paraffin, polyethylene and the like can be mentioned.

(vii) Alcohol compound C6-C22 linear or branched monohydric alcohol, polyhydric alcohol, these C2-C4 oxyalkylene group adducts, etc. are mentioned. Furthermore, an ether compound in which an alkyl group is added to a part or all of the terminal of the alcohol is also included.

  The polyhydric alcohol is preferably a 2-14 valent alcohol having 2 to 24 carbon atoms which may contain an ether group, more preferably a 2-8 valent alcohol, and particularly preferably a 3-6 valent alcohol.

  Examples of the dihydric alcohol include those having a total carbon number of 2 to 10 which may contain an ether group, such as propylene glycol, dipropylene glycol, butylene glycol, dibutylene glycol, ethylene glycol, diethylene glycol, and polyethylene glycol.

  As trihydric or higher alcohols, alcohols having a total carbon number of 3 to 24 which may have an ether group, those having a total number of hydroxyl groups / total number of carbons in one molecule = 0.4 to 1, such as glycerin, poly Examples include glycerin (average condensation degree 2 to 5), pentaerythritol, dipentaerythritol, arabitol, sorbitol, stachyose, erythritol, arabit, mannitol, glucose, sucrose, and the like.

  More preferably ethylene glycol, diethylene glycol, propylene glycol, an alcohol having 3 to 12 total carbon atoms which may have an ether group, and having 3 or more valences, wherein the number of hydroxyl groups in one molecule / total number of carbons = 0.5 to 1. It is alcohol. Particularly preferred are glycerin, polyglycerin (average condensation degree 2 to 4), and pentaerythritol.

  Examples of the ether compound include a glyceryl ether compound, and a compound represented by the following general formula (a) is preferable.

(In the formula, R ₁ is an alkyl group, alkenyl group or β-hydroxyalkyl group having 8 to 35 carbon atoms.)
(viii) Compound having a carbonyl group and an alkyl group in the molecule Fatty acid, ester of fatty acid and alcohol, fatty acid amide, fatty acid amide amine, or an adduct of these oxyalkylene groups having 2 to 4 carbon atoms, rosin, alkyl ketene dimer, alkenyl And succinic anhydride.

  Examples of the fatty acid include fatty acids having 1 to 24 carbon atoms, preferably 10 to 22 carbon atoms, and may be saturated, unsaturated, linear or branched, and linear fatty acids are particularly preferable. More preferred are lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid and oleic acid, with stearic acid being particularly preferred.

  Specific examples of the alcohol include those exemplified in (vii) alcohol compounds.

  These esters can be obtained by known esterification reactions and alkylene oxide addition reactions. For example, if necessary, an esterification catalyst is added to a mixture of fatty acid and polyhydric alcohol and reacted at 150 to 250 ° C. to obtain an ester. Further, an alkylene having 2 to 4 carbon atoms in the presence of an alkali catalyst or the like. By adding an oxide, an alkylene oxide addition ester is obtained. Further, esterification may be performed after adding alkylene oxide to fatty acid or polyhydric alcohol. Further, it may be obtained by adding only an alkylene oxide to a fatty acid.

  The ester average substitution degree of this ester is preferably one in which 10 to 95 equivalent% of OH in the alcohol is substituted per 1 mol of polyhydric alcohol, and particularly preferably 1 to 2 mol per 1 mol of polyhydric alcohol. Have an ester group.

  When an alkylene oxide addition ester is used, the average addition mole number of alkylene oxide (AO) is more than 0 mol and less than 12 mol on an average per mol of ester, and preferably 0.1 to 6 mol. In addition, when polyhydric alcohols that can be AO groups such as ethylene glycol are used, these are also included in the number of AO groups. The alkylene oxide is preferably ethylene oxide (EO) or propylene oxide (PO). These may be either EO, PO alone or a mixture of EO and PO. In the present invention, it is particularly preferable to use a polyhydric alcohol not containing an AO group and an ester of a fatty acid.

  In particular, an ester compound of alcohol and stearic acid selected from glycerin, polyglycerin (average condensation degree 2 to 4), and pentaerythritol is preferable.

(Emulsifying substance)
An emulsified substance is a component contained as needed. The emulsified material may be any material that can emulsify the oil-based papermaking chemicals. In addition to general emulsifiers, the emulsified state (in two types of liquids that are difficult to dissolve each other, one is a continuous phase and the other is a fine particle dispersed phase As long as it can form a relatively stable system).

  Examples of the emulsifying substance include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and polymeric substances that emulsify with protective colloid ability and surfactant ability.

  Nonionic surfactants include glycerin fatty acid esters, sucrose fatty acid esters, and polyoxyalkylene ethers, and anionic surfactants include fatty acid salts, alkylbenzene sulfonates, and alkyl sulfate esters. Examples of ionic surfactants include alkylamine salts and quaternary ammonium salts, and examples of amphoteric surfactants include alkylbetaines and amine oxides.

  Polymeric substances include cellulose-based materials such as cationized cellulose and methylcellulose; starch-based materials such as alkyl starch, cationized starch, and octenyl succinic starch; polysaccharide-based materials such as gum arabic, guar gum, and xanthan gum; casein Proteins such as sodium; polyvinyl alcohol, and synthetic polymers having a cation group and an alkyl group in one molecule.

  Among these, cationized cellulose, cationized starch, synthetic polymers having a cation group and an alkyl group in one molecule, etc., which have a cationic property in water, impart a cationic property to oily papermaking chemicals, pulp, etc. This is preferable because the fixing property to (the surface is negatively charged in water) can be enhanced.

  Furthermore, synthetic polymers with a cation group and an alkyl group in one molecule can be used in the emulsion and emulsion drying processes by adjusting the ratio and molecular weight of the cation group / alkyl group according to the properties of the papermaking agent. It is preferable because the stability can be improved.

(Other ingredients)
The papermaking drug particles of the present invention may contain other components of the kind and amount that do not impair the emulsion stability in water, such as dispersants, coloring substances, solvents, and inorganic salts.

(Content of each component)
The content of the water-soluble solid matrix in the papermaking drug particles is preferably from 5 to 90% by weight, more preferably from 10 to 70% by weight, from the viewpoint of suppressing the manufacturing cost and increasing the dispersibility of the oily papermaking drug. 20 to 50% by mass is more preferable.

  The content of the oil-based papermaking drug in the papermaking drug particles is preferably 10 to 95% by mass, more preferably 30 to 90% by mass from the viewpoint of suppressing the manufacturing cost and increasing the dispersibility of the oily papermaking drug. 50 to 80% by mass is more preferable.

  The content when the emulsified substance is contained in the papermaking drug particles is adjusted according to the type and amount of the oily papermaking drug, the target oil droplet diameter, etc., but is preferably 0.1 to 30% by mass, 0.5 to 20 mass% is more preferable, and 1-10 mass% is still more preferable.

  However, modified starch and the like include substances having both matrix forming ability and emulsifying action, and in that case, the total amount is preferably within the above range.

<Method for producing papermaking drug particles>
The manufacturing method of the papermaking drug particle of this invention is demonstrated for every process. Each of the following processes may be an independent process, or two or more processes may be a single continuous process. Furthermore, other steps can be added as necessary.

  In the first step, the water-soluble solid matrix forming agent is dissolved in water adjusted to a temperature equal to or higher than the melting point of the oil-based papermaking chemical, and in the subsequent step, the aqueous solution of the water-soluble solid matrix forming agent obtained in the previous step is converted into an aqueous solution. An oily papermaking chemical and an emulsifying substance are added, and the oily papermaking chemical is emulsified to obtain an emulsion.

  The amount of water is preferably 20 to 80 parts by mass, more preferably 25 to 70 parts by mass, and still more preferably 30 to 60 parts by mass when the total amount of the emulsion is 100 parts by mass. When the blending amount of water is 20 parts by mass or more, the emulsified substance functions sufficiently, so that a stable emulsion can be obtained. When the blending amount of water is 80 parts by mass or less, the amount of water removed in the drying step is small, so that productivity is improved.

In this process, the oil-based papermaking chemical is stably emulsified and dispersed so as to have a desired oil droplet diameter (volume average 0.1 to 50 μm). It is preferable to use a high-pressure emulsifier such as a mold emulsifier and a homogenizer, and a line mixer.
In the case where the emulsified substance includes a substance that is cationic in water, it is preferable to adjust the pH of the emulsion to an acid before the drying step from the viewpoint of preventing coalescence of the oily papermaking chemicals. . This is considered to be derived from the fact that the cationic property of the emulsified substance is further increased in the acidic liquid. As a result, it is considered that the function as an emulsifier is increased and the encapsulation state is improved. The pH of a solution obtained by diluting an emulsion (emulsion) with water so as to have a solid content of 10% by weight is preferably 2 to 6, and more preferably 3 to 5.
Moreover, as an adjustment method to the acidic region of pH, the emulsion may be acidic due to the acidic component derived from each raw material, and an acidic component such as phosphoric acid is added and mixed in any of the emulsion adjustment steps. By doing so, the pH may be adjusted.

  In the next step, the emulsion obtained in the previous step is dried. It is preferable that the drying temperature in this step is equal to or higher than the melting point of the target papermaking drug particles because aggregation of oil droplets in the drying step can be suppressed. Specifically, it is desirable to perform a drying treatment within a range of 100 to 250 ° C.

  By drying at a temperature equal to or higher than the melting point of the oil-based paper making agent in this manner, the oil-based paper making agent remains in the state of oil droplets (while the oil droplet diameter remains in the state of 0.1 to 50 μm on a volume basis average). Dispersed and immobilized in a water-soluble solid matrix. For this reason, even if it preserve | saves below melting | fusing point after granulation, or it is made to melt | dissolve in water below melting | fusing point for adding to a papermaking process, an aggregate is hard to produce.

  As the drying method, spray drying, vacuum drying, freeze drying, belt drying, shelf drying, drum drying, and the like can be applied. Among these drying methods, the spray drying method is preferable.

  Thereafter, the obtained papermaking drug particles can be subjected to secondary processing according to the purpose. For example, processing such as coating for the purpose of removal of fine powder and coarse powder by sieving, adjustment of particle diameter by granulation or grinding operation, shape processing, coloring with pigments and dyes, stability improvement, etc. it can. In addition, for the purpose of improving stability and quality in a papermaking scene, a dispersant and a stabilizer may be blended to form a composition containing papermaking drug particles.

<Application to papermaking>
The papermaking chemical particles of the present invention can be widely applied to mechanical pulp such as thermomechanical pulp (TMP), virgin pulp such as chemical pulp such as LBKP, pulp raw material such as waste paper pulp, and mixed raw materials thereof.

  The papermaking chemical particles of the present invention are added to the pulp slurry and the water used before the papermaking process (internal addition) in the papermaking process. The addition location is before the papermaking process where a thin liquid of pulp raw material is filtered while traveling on the wire mesh to form a paper layer, and a tank such as a mixing chest, a seed box, a machine chest, a head box, a white water tank, or the like. It may be added to piping connected to these facilities (fan pump or the like), but a place where it can be uniformly blended with the pulp raw material, such as mixing chest, seed box, machine chest or fan pump, is desirable.

  If necessary, along with the papermaking chemical particles, sizing agents, fillers, yield improvers, drainage improvers, paper strength improvers, aluminum sulfate, compounds having an acrylamide group, polyethyleneimine and other fixing accelerators (to pulp) (Fixing accelerator) or the like may be used in combination, but these components are preferably added separately from the papermaking drug particles of the present invention in the paper manufacturing process.

  When the papermaking drug particles of the present invention are applied to a papermaking method, when added to a pulp raw material containing water, the water-soluble solid matrix dissolves in water, and oil droplets (oil-based papermaking chemical) are quickly dispersed, and the pulp raw material Mixed with. Then, the paper is made as it is and oil droplets (oil-based papermaking chemicals) remain in the pulp sheet, so that the function of the chemicals is exhibited.

  In the production method of the present invention, the papermaking drug particles exhibit an effect of improving paper quality even when added in an amount of 0.01 to 5 parts by weight, particularly 0.1 to 2 parts by weight, based on 100 parts by weight of the pulp raw material. Workability is improved.

  In addition, the pulp sheet obtained by applying the production method of the present invention is a newspaper roll paper or printing in the item classification described in the Paper Pulp Technology Handbook (issued by the Paper Pulp Technology Association, pages 455-460, 1992). -It is suitably used for paper such as information paper, packaging paper, sanitary paper, or paperboard.

(1) Components used (Water-soluble solid matrix forming agent)
EMALSTAR 30: Processed starch manufactured by Matsutani Chemical Industry Co., Ltd. Paindex # 2: Maltodextrin manufactured by Matsutani Chemical Industry Co., Ltd.
Bulking agent A: Pentaerythritol stearate, average ester substitution degree 45 equivalent%, melting point about 50 ° C.
(Emulsifying substance)
Cationized starch 1: Cationized tapioca starch (N% = 0.04%)
Cationized starch 2: Cationized corn starch (N% = 0.6%)
Sugar Ester S270: Emulsifier manufactured by Mitsubishi Chemical Foods Co., Ltd. Cationic polymer 1: Synthetic polymer polymerized with lauryl methacrylate / dimethylaminoethyl methacrylate methyl chloride quaternized product = 15 mol% / 85 mol% (weight average molecular weight 100,000) )
Cationic polymer 2: Diethyl sulfate quaternized product of stearyl methacrylate / dimethylaminoethyl methacrylate = 2/98 mol% synthetic polymer (weight average molecular weight 80,000)
Cationic polymer 3: Diethyl sulfate quaternized product of behenyl methacrylate / dimethylaminoethyl methacrylate = 2/98 mol% Synthetic polymer (weight average molecular weight 80,000)
The weight average molecular weight was measured by GPC under the following measurement conditions. Polyethylene glycol (standard sample for GPC) was used for the converted molecular weight.
<Measurement conditions>
Column: α-Mx2 (Tosoh product)
Eluent: 50 mM LiBr, 1% acetic acid / ethanol = 70/30 (volume ratio)
Flow rate: 0.6 ml / min
Column temperature: 40 ° C
Detector: RI
Sample concentration: 2 mg / ml
Injection volume: 100 μL
(2) Evaluation method (Measurement of oil droplet diameter of oil-based papermaking chemicals)
It was measured by a light scattering method using LA-910 manufactured by HORIBA, Ltd. using water as a dispersion medium.

(Average particle size of drug particles for papermaking)
Measurement was performed by a light scattering method using LA-910 manufactured by HORIBA, Ltd. using ethanol as a dispersion medium. However, for those having an average particle size exceeding 50 μm, the dry sieving method defined in JIS K-3362 was used because the large particle size may not be measured well by sedimentation. The average particle diameter measured by this method is based on mass, but the value is substituted. In the examples, the numerical value of 50 μm or less is a volume-based average particle diameter measured by a light scattering method, and the numerical value exceeding 50 μm is a mass-based average particle diameter by a dry sieving method.

(Addition rate with agent)
The addition mass% of the chemical | medical agent with respect to a pulp is shown. Existence indicates the amount of drug (the papermaking drug particle of the present invention or KB115) added without considering the content of the main base.

(Kett moisture)
The loss on drying measured with a Kett moisture meter is shown. The measurement conditions were an infrared moisture meter FD-240-2 manufactured by Kett Science Laboratory, sample 2 g, 105 ° C., 30 sec AUTO (finished when there was no mass change for 30 seconds).

Average particle size (710 PASS), 710 PASS rate When the powder obtained by spray drying is sieved with a standard sieve having a mesh size of 710 μm, the sieve passing rate is 710 PASS rate. The mass standard average particle diameter measured by the dry sieving method specified in 3362 was defined as the average particle diameter (710 PASS). The higher the 710PASS rate, the higher the productivity.

(Cold water dispersibility)
Add 900g of water at 20 ° C to a 2L beaker, add 100g of sample while stirring so that the deepest part of the vortex becomes 500ml with 4 flat blades, and visually observe the state after 30 minutes At the same time, the oil droplet diameter was measured (light scattering method using LA-910 manufactured by Horiba, Ltd.).

(Bulk improvement rate)
The bulk improvement effect by the bulking agent A was determined by measuring the tightness of paper made under the following conditions.

Bulk improvement rate = [(tensity of sample-free product) / (tensity of sample-added product) -1] × 100 (%)
Papermaking method: 1% by mass of LBKP pulp slurry was weighed so that the basis weight of the sheet after papermaking would be 80 g / m ² , and with stirring, 0.5% aluminum sulfate (vs. pulp) as cationized starch Cato302 (manufactured by Nippon NSC Co., Ltd.) 0.3%, Silene-94 (manufactured by Kao Corporation) 0.2% as an AKD sizing agent, and Whiten PC (manufactured by Shiraishi Kogyo Co., Ltd.) 15 as light calcium carbonate % Were sequentially added and then diluted to a pulp concentration of 0.5%.

  Further, the papermaking drug particles of the examples or the bulking agent of the comparative example were diluted in water or added as they were, with stirring, at room temperature (20-25 ° C) (dispersion concentrations shown in Tables 1 and 2), and the yield. 0.015% by mass of Percoll 47 (Ciba Specialty Chemicals Co., Ltd.) was added as an agent.

This was made with a round tappy paper machine with a 150 mesh wire to obtain a wet paper, and then two wet papers on each side of Advantech. The sample was sandwiched between 26 round filter papers, pressed at 3.5 kg / cm ² for 5 minutes, and dried at 105 ° C. for 2 minutes using a mirror dryer. The dried sheet was conditioned at 23 ° C. and 50% RH for 1 day, and then measured for each item shown in Table 1, Table 2, and Table 3.

Tightness: basis weight (g / m ² ) and thickness (μm) of paper are measured, and the tightness (g / m ³ ) is determined by the following formula: basis weight / thickness. The smaller the absolute value is, the higher the bulk is, and the difference of 0.02 is sufficiently recognized as a significant difference.

(Oil spot judgment method)
The presence or absence of oil droplets on the paper was visually observed.

Comparative Example 1
As an oil-based papermaking agent, a bulking agent for papermaking KB-115 (manufactured by Kao Corporation) was used.

Comparative Example 2
180 kg of hot water at 85 ° C. was charged into a blending tank with a jacket through which 90 ° C. warm water was passed, and 20 kg of KB-115 was charged with stirring to dissolve. After confirming that KB-115 was dissolved and the liquid temperature reached 80 ° C. or higher, circulation emulsification was performed with a line mixer (1 hour). At the end of emulsification, the mixture was sent to a storage tank while rapidly cooling to 50 ° C. or lower through a heat exchanger. The resulting bulking agent had an average oil droplet diameter of 5.3 μm.

Example 1
Using the components shown in Table 1 (4 kg in total of 40% papermaking drug particles and 60% water), papermaking drug particles were obtained by the method shown below.

  Weigh water, paindex # 2, cationized starch 1 and Emulster 30 into a 10L metal container, and place the metal container in a 95 ° C hot water tank. Homomixer (Special Machine Industries Co., Ltd.) The solution was stirred until the liquid temperature reached 90 ° C. Emulster 30 was sufficiently gelatinized by maintaining at 90 ° C. or higher for 10 minutes.

  Thereafter, the temperature of the hot water tank was changed to 85 ° C., while continuing stirring, the bulking agent A (melting point: about 50 ° C.) was added and emulsified for 60 minutes. A part of the obtained emulsion was poured into water at room temperature under stirring and rapidly cooled to obtain a sample for oil droplet diameter measurement (oil droplet diameter was 4.2 μm).

  While maintaining the obtained emulsion at 70 ° C or higher, it was supplied to the spray drying tower (TSR-5W2N manufactured by Sakamoto Giken Co., Ltd.) at a rate of 100 g / min and atomized with a two-fluid nozzle (dispersed gas was compressed) Use air). Hot air of 200 ° C. was supplied to the drying tower and dried, and the dried product was separated and collected by a cyclone. As a result, papermaking drug particles having an average particle size of about 50 μm were obtained. Table 1 shows the measurement results.

Example 2
Using each component shown in Table 1 (130 kg in total of 40% papermaking drug particles and 60% water), papermaking drug particles were obtained by the following method.

  Water was charged into a 300 L jacketed mixing tank, and under stirring, Paindex # 2 and cationized starch 2 were added, and 85 ° C. warm water was added to the jacket to raise the liquid temperature to 75 ° C. or higher.

  Thereafter, a molten mixture of sugar ester S270 and bulking agent A (melting point: about 50 ° C.) previously mixed at a temperature of 70 ° C. or higher was added. After mixing for 30 minutes, the mixture was circulated and emulsified for 2 hours at 6600 rpm in a line mixer (T.K., Pipehomomixer SL-2, manufactured by Tokushu Kika Kogyo Co., Ltd.). A part of the obtained emulsion was poured into water at room temperature under stirring and rapidly cooled to obtain a sample for oil droplet size measurement (oil droplet size was 6.1 μm).

  While maintaining the obtained emulsified liquid at 70 ° C. or higher, 30 μl / hr in a co-current type spray drying tower (column diameter 3.2 m, nebulizer: RA-302MZ (rotor diameter 120 mm) manufactured by Ashizawa Niro Atomizer Co., Ltd.) It was fed at a speed and dried under the conditions of an atomizer rotational speed of 4000 r / m and a blast of 180 ° C., and dried powder was obtained from the tower lower outlet. As a result, drug particles for papermaking having an average particle size of about 200 μm and a water content of about 2% were obtained. Table 1 shows the measurement results.

  In the evaluation of cold water dispersibility, KB115 of Comparative Example 1, which is a solid at room temperature, is not dispersed in room temperature water and floats as a lump, and a chemical solution that can be added to the papermaking process cannot be obtained. In order to make this a chemical solution that can be added to the papermaking process, facilities such as heating, dissolution, emulsification, and rapid cooling are required.

  On the other hand, all of the papermaking drug particles of the present invention have an oil droplet diameter of 50 μm or less and have good dispersibility in water at room temperature, so that a chemical solution that can be easily added to the papermaking process can be obtained. The paper-making drug particles of the present invention are excellent in storability because of their particulate form.

  Further, in papermaking evaluation, the papermaking drug particles of the present invention were found to have the same bulk improvement effect as Comparative Example 2.

Comparative Example 3
In the same manner as in Comparative Example 2, a bulking agent (oil droplet diameter: average 5.3 μm) was obtained. Table 2 shows the measurement results. However, the kind of addition ratio to pulp in papermaking evaluation is different from that in Comparative Example 2.

Examples 3 and 4
Using the components shown in Table 2 (230 kg each for a total of 40% papermaking drug particles and 60% water), papermaking drug particles were obtained by the following method.

  Water was charged into a 300 L jacketed blending tank, the cationic polymer was added under stirring, and 85 ° C. warm water was added to the jacket to raise the liquid temperature to 75 ° C. or higher.

  Bulking agent A (melting point: about 50 ° C.) was added and mixed for 30 minutes, and then circulated and emulsified for 20 minutes at 6600 rpm with a line mixer (TK, Piper Homomixer SL-2, manufactured by Tokushu Kika Kogyo Co., Ltd.). . While continuing the circulation emulsification, Paindex # 2 was added, and the circulation emulsification was further continued for 1 hour to obtain an emulsion. A part of the obtained liquid was rapidly cooled by being poured into water at room temperature with stirring to obtain a sample for oil droplet diameter measurement (the oil droplet diameter was 2.0 μm in Example 3 and 2.3 μm in Example 4). )

  While maintaining the obtained emulsified liquid at 70 ° C. or higher, the flow rate was 30 L / hr in a co-current type spray drying tower (column diameter 3.2 m, sprayer: RA-302MZ (rotor diameter 120 mm) manufactured by Ashizawa Niro Atomizer Co., Ltd.). The powder was supplied at a speed and dried under the conditions of an atomizer rotational speed of 4000 r / m and a blowing air of 180 ° C., and dried powder was obtained from the tower lower outlet. As a result, paper drug particles having an average particle size of about 200 μm and a water content of about 2% were obtained.

  Table 2 shows the measurement results. A cross-sectional photograph (scanning electron micrograph) of the papermaking drug particles obtained in Example 4 is shown in FIG.

  In the papermaking drug particles of Examples 3 and 4, since the cationic polymer is used as the emulsifying substance, the oil droplet diameter of the emulsion liquid and the oil droplet diameter of the dispersion liquid are in good agreement. Among them, it is considered that the oil-based papermaking chemical is well dispersed and fixed.

  In the papermaking drug particles of Example 4, an increase in the bulk improvement effect was recognized as compared with Comparative Example 3, which was due to the use of a cationic polymer having a high cation density as an emulsifier to improve the fixing rate to the pulp. It is thought that.

  From the SEM photograph of FIG. 1, it was confirmed that the papermaking drug particles had a hollow portion at the center, and the remaining cross section had a dense structure having fine pores. It is preferable to form particles having such a hollow portion because disintegration when dispersed in water is enhanced and dispersibility in water is enhanced.

Examples 5-8
Using each component shown in Table 3 (each 200 kg in total of 50% papermaking drug particles and 50% water), papermaking drug particles were obtained by the following method.
Water was charged into a 300 L jacketed mixing tank, the cationic polymer was added under stirring, then Pinetex # 2 was added, 85 ° C. warm water was added to the jacket, and the liquid temperature was raised to 75 ° C. or higher.
When bulking agent A (melting point: about 50 ° C) is added and phosphoric acid is added, after adding phosphoric acid and mixing for 30 minutes, pressure loss is applied to the static disperser (Fujikin Co., Ltd.). Was passed through at a flow rate of 0.9 MPa and circulated and emulsified for about 1 hour to obtain an emulsion. A part of the obtained liquid was quenched into a room temperature water by stirring to prepare a sample for oil droplet diameter measurement.
The obtained emulsion was kept at 70 ° C. or higher and supplied to the same co-current type spray drying tower as in Example 3. The sprayer was equipped with one fluid pressure nozzle (SSTX- from Spraying Systems Japan Co., Ltd.). 3. Orifice diameter φ0.86mm), spraying and drying under conditions of spraying pressure 1.8MPa and blowing temperature 175 ℃, dried powder was obtained from the tower lower outlet. Table 3 shows the measurement results.

Measuring method of pH: The emulsion immediately after the preparation was added to water at room temperature while stirring to adjust the solid content concentration to 10%. The container containing the obtained liquid was immersed in a hot water tank in a sealed state, and the liquid temperature was adjusted to 25 ° C. The pH of this solution was measured using a pH meter F-52 manufactured by Horiba, Ltd.
Comparing Example 5 with Example 6 and Example 7 with Example 8, the degree of encapsulation (difference between oil droplet size in emulsion and re-dispersed oil droplet size in powder depends on the type of cationic polymer as emulsifier. ) Are changing, indicating the importance of the cationic polymer. In addition, comparison between Example 6 and Example 7 shows that the degree of encapsulation can be changed by adjusting the pH of the emulsifier even with the same cationic polymer. The difference between the oil droplet diameter in the emulsion and the re-dispersed oil droplet diameter of the powder is considered to indicate the degree of the phenomenon that the oil droplets in the emulsion are coalesced during the production of the drug particles. The smaller this difference, the higher the degree of encapsulation and the better.

Sectional drawing by the scanning electron micrograph of the papermaking chemical | medical agent particle obtained in Example 4. FIG.

Claims (3)

  A step of dissolving a water-soluble solid matrix forming agent in water at a temperature equal to or higher than the melting point of the oily papermaking chemical, then adding an oily papermaking chemical and, if necessary, an emulsifying substance, emulsifying the oily papermaking chemical and emulsifying it And a method for producing papermaking drug particles, comprising the step of drying the emulsion at a temperature equal to or higher than the melting point of the oily papermaking drug. The method according to claim 1 for papermaking drug particles according drying method is spray drying. Emulsion material contains a shows the cationic in water, method for producing papermaking drug particles of claim 1 including the step of adjusting the pH of the emulsion prior to drying acidic.