JP3162477B2 - Self-dispersing aqueous polyester resin composition, method for producing the same, and paper surface treating agent composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-dispersible water-based polyester resin composition, a method for producing the resin composition characterized by a phase inversion method, an electrophotographic paper using the water-based polyester resin composition, and an electrostatic. The present invention relates to a surface treating agent composition for paper such as recording paper or thermal transfer paper.

[0002]

2. Description of the Related Art An aqueous resin dispersion can be used as a property improving agent for surface coating, adhesion, etc. by coating or impregnating the surface of paper, woven fabric, nonwoven fabric or the like. . Conventionally, most of such aqueous resin dispersions are produced by an emulsion polymerization method, and in order to maintain the stability of the polymerization reaction and the resulting aqueous resin dispersion, several percent of emulsifier is used during production. I have.
Usually, in order to obtain an aqueous resin dispersion having a small particle size by this formulation, a relatively large amount of an emulsifier is required.

However, emulsifiers have harmful side effects such as lowering the water resistance, adhesion, adhesion, weather resistance, mechanical strength and the like of the dried film. As a method for solving these problems, a soap-free emulsion polymerization method has attracted attention. Details of such a polymerization method are described in many documents. For example, Yamazaki et al., “New Development and Problems of Synthetic Polymer Latex” [Chemical Industry Data (Toko Test News) vo
l. 13 (4) P3 (1978)], but the aqueous resin dispersion obtained by soap-free emulsion polymerization is not practical because it has a problem that shelf stability and mechanical stability are extremely poor. .

On the other hand, as a conventional electrophotographic method, as described in US Pat. Nos. 2,297,691 and 2,357,809, etc., a photoconductive insulating layer is uniformly charged, and then the layer is exposed. An electric latent image is formed by dissipating the electric charge on the exposed portion, and the latent image is visualized by adhering a fine powder having a colored electric charge called toner (developing step). ), The obtained visible image is transferred to a transfer material such as transfer paper (transfer step), and then permanently fixed by heating, pressure or other appropriate fixing method (fixing step). In the fixing step of these steps, by controlling the material and physical properties of the binder resin constituting the toner,
Low energy fixing is being promoted. However,
Regarding paper and the like on which the toner is fixed, the use of neutral paper and recycled paper has been promoted, but few attempts have been made to improve the toner for the purpose of improving the fixability. Therefore, an attempt to improve the fixability of paper or the like by using a surface modifier or the like at the time of production can be considered. However, when the aqueous resin dispersion is used, the water resistance, mechanical strength, and the like of the film are as described above. There were problems such as a decrease, and there was a need to improve these.

The present invention has been made to satisfy the above-mentioned requirements, and an object of the present invention is to provide a self-dispersible water-based polyester resin having high water resistance of a dried film because an emulsifier is not used, and a method for producing the same. It is in. Another object of the present invention is to provide a paper surface treating composition using the self-dispersible aqueous polyester resin for improving the low-temperature fixability of the toner.

[0006]

That is, the present invention provides (1) (a) a diol component represented by the following formula:

[0007]

Embedded image

(Wherein, R represents an ethylene or propylene group, x and y are each an integer of 1 or more, and x +
The average value of y is 2-7. (B) at least one alcohol component selected from the group consisting of (b) aliphatic diols and (c) trihydric or higher polyhydric alcohols; and (d) dihydric carboxylic acids, acid anhydrides or lower alkyl esters thereof. And (e) an acid value obtained by copolycondensation of at least one acid component selected from the group consisting of a trivalent or higher polycarboxylic acid, an acid anhydride thereof, and a lower alkyl ester thereof, from 3 to 70K.
OH mg / g polyester resin is dissolved in a ketone solvent, a neutralizing agent is added to ionize the carboxyl group of the polyester resin, and then water is added. A self-dispersible aqueous polyester resin composition , (2) (a) a diol component represented by the following formula,

[0009]

Embedded image

(Wherein, R represents an ethylene or propylene group, x and y are each an integer of 1 or more, and x +
The average value of y is 2-7. (B) at least one alcohol component selected from the group consisting of (b) aliphatic diols and (c) trihydric or higher polyhydric alcohols; and (d) dihydric carboxylic acids, acid anhydrides or lower alkyl esters thereof. And (e) an acid value obtained by copolycondensation of at least one acid component selected from the group consisting of a trivalent or higher polycarboxylic acid, an acid anhydride thereof, and a lower alkyl ester thereof, from 3 to 70K.
OH mg / g polyester resin is dissolved in a ketone solvent, a neutralizing agent is added to ionize the carboxyl group of the polyester resin, and then water is added. A method for producing a self-dispersing aqueous polyester resin composition , and (3) containing the self-dispersing aqueous polyester resin composition described in (1) above as a component of a paper surface treating agent. The present invention relates to a characteristic surface treatment agent composition for paper.
The self-dispersion type aqueous polyester resin composition of the present invention
Is a polyester in which the polyester resin is dispersed in an aqueous system
It is a resin composition.
Self-dispersible water-based polyester resin ''
You.

The polyester resin used for producing the self-dispersible water-based polyester resin of the present invention is produced by using an alcohol component and an acid component such as carboxylic acid, an acid anhydride thereof or a lower alkyl ester thereof as a raw material monomer. As the alcohol component, dihydric alcohols (a) and (b) described later and trihydric or higher polyhydric alcohols (c) are used, and carboxylic acids, acid anhydrides or lower alkyl esters thereof are described later ( D) divalent carboxylic acid and the like and (e) trivalent or more polyvalent carboxylic acid and the like are used. Examples of the diol (a) include a diol represented by the following formula:

[0012]

Embedded image

(Wherein, R represents an ethylene or propylene group, x and y are each an integer of 1 or more, and x +
The average value of y is 2-7. Specifically, for example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4-hydroxyphenyl)
Propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0)-
Examples thereof include alkylene oxide adducts of bisphenol A such as 2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane.

Examples of the aliphatic diol (b) include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol,
3-propylene glycol, 1,4-butanediol,
Neopentyl glycol, 1,4-butenediol,
Examples thereof include 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

Examples of the trihydric or higher polyhydric alcohol (c) include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4, -butanetriol, 1,2,5,-
Pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4, -butanetriol, trimethylolethane, trimethylolpropane, 1,3,5, -trihydroxymethylbenzene and the like. In the present invention, at least one selected from the group consisting of the above-mentioned alcohol components (a) to (c) is used.
The diol component (b) is used in an amount of less than 20 mol% in the total alcohol component. The trihydric or higher alcohols of (c) are used in less than 60 mol% of all alcohol components. If it is 60 mol% or more, it becomes insoluble in a ketone solvent and phase inversion becomes difficult.

Examples of the dicarboxylic acid (d), the acid anhydride or the lower alkyl ester thereof include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and the like. Succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n
-Octenyl succinic acid, n-octyl succinic acid, isooctenyl succinic acid, isooctyl succinic acid, etc., or anhydrides or lower alkyl esters of these acids.

The trivalent or higher carboxylic acid (e), its acid anhydride or its lower alkyl ester of (e) includes, for example, 1,2,4-benzenetricarboxylic acid, 2,5,7,
-Naphthalenetricarboxylic acid, 1,2,4, -naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-
Dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,2
Examples thereof include 7,8, -octanetetracarboxylic acid, pyromellitic acid, and empole trimer acid, and anhydrides or lower alkyl esters of these acids. In the present invention, at least one selected from the group consisting of the acid components (d) to (e) is used, and the divalent carboxylic acid (d) is used in an amount of 40 to 100 mol% based on the total acid components. And
The trivalent or higher polycarboxylic acid (e) is 6% of the total acid components.
It is used at less than 0 mol%. When it is 60 mol% or more,
It becomes insoluble in ketone solvents and phase inversion becomes difficult. (C)
When a trihydric or higher polyhydric alcohol is used in combination with a trihydric or higher polycarboxylic acid derivative of (e), 30
It is used in less than mol%. If it is at least 30 mol%, it will be insoluble in ketone solvents and phase inversion will be difficult. For the purpose of controlling the terminal group and the molecular weight, a monohydric alcohol and a monovalent carboxylic acid derivative can be used at 10 mol% or less, respectively.

The polyester resin used in the present invention comprises:
It is obtained by co-condensation polymerization of the above raw material monomers. As the method of the copolycondensation, a known method is used without any particular limitation. The polyester resin used in the present invention preferably has an acid value (according to JIS K 0070) of 3 to 70 KOH mg / g, more preferably 5 to 60 KOH mg / g. 3KOHm
If it is less than g / g, a stable self-dispersion type aqueous polyester resin dispersion cannot be obtained. On the other hand, the acid value is 70 KOHmg / g
Exceeding the range is not preferred because the water resistance after application to a coating film or paper is poor. Here, the acid value of the resin can be adjusted by changing the composition ratio of the acid component and the alcohol component, using a carboxylic acid ester, or blocking the acid value with a monohydric alcohol. The polyester resin used in the present invention preferably has a glass transition temperature of 25 ° C. or higher as measured by DSC (differential scanning calorimeter).
If the temperature is lower than 25 ° C., it is not preferable that the paper is transferred to an aqueous system, the paper is applied to the paper, and then the paper is placed on the paper under high temperature and high humidity (35 ° C., 80% RH). Here, the glass transition temperature of the resin can be adjusted by changing the composition ratio of the constituent monomers.

The polyester resin used in the present invention comprises:
It is preferable that the number average molecular weight is 2,500 to 70,000. If it is less than 2,500, the physical properties of the coating film formed using the resin after phase inversion are inferior, and if it exceeds 70,000, the viscosity becomes high in the phase inversion step, which is not preferable.

In the method for producing a self-dispersible water-based polyester resin of the present invention, the polyester resin having a predetermined acid value is dissolved in a ketone solvent, and a neutralizing agent is added to ionize the carboxyl groups of the polyester resin. Then, after adding water, the ketone-based solvent is distilled off and the phase is changed to an aqueous phase. More specifically, for example, a reactor equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas inlet tube is prepared, and a polyester resin having a predetermined acid value dissolved in a ketone-based solvent is prepared. It is obtained by adding a wetting agent or the like, ionizing the carboxyl group (it is unnecessary if it has already been ionized), and then adding water, then distilling off the ketone-based solvent and inverting the aqueous phase. The dissolution in the ketone-based solvent and the addition of the neutralizing agent are usually performed at a temperature not higher than the boiling point of the ketone-based solvent, and examples of water used here include ion-exchanged water.

The ketone solvents used at this time include, for example, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, methyl isobutyl ketone,
Methyl isopropyl ketone and the like, preferably,
Methyl ethyl ketone. Examples of the neutralizing agent include an aqueous alkali solution such as aqueous ammonia and sodium hydroxide, allylamine, isopropylamine, diisopropylamine, ethylamine, diethylamine, triethylamine, 2-ethylhexylamine, 3-ethoxypropylamine, diisobutylamine, and 3-diethylamino. Propylamine, tri-n-octylamine, t-butylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, n-propanolamine, butanolamine,
-Amino-4-pentanol, 2-amino-3-hexanol, 5-amino-4-octanol, 3-amino-
3-methyl-2-butanol, monoethanolamine,
Isopropanolamine, neopentanolamine, diglycolamine, ethylenediamine, 1,3-diaminopropane, 1,2-diaminopropane, 1,6-diaminohexane, 1,9-diaminononane, 1,12-diaminododecane, dimer Body fatty acid diamine, 2,2,4
-Trimethylhexamethylenediamine, 2,4,4,-
Examples thereof include amines such as trimethylhexamethylenediamine, hexamethylenediamine, N-aminoethylpiperazine, N-aminopropylpiperazine, N-aminopropyldipiperidipropane, and piperazine.
The amount of the neutralizing agent used may be an amount capable of neutralizing at least the acid value of the polyester resin.

The number average molecular weight of the self-dispersible aqueous polyester resin thus obtained is usually from 2,500 to 7
It is 0000. This corresponds to the molecular weight of the polyester resin used for phase inversion. The particle size of the obtained self-dispersible aqueous polyester resin is preferably from 0.001 to 10.0 μm, more preferably from 0.1 to 10.0 μm.
001 to 1.0 μm. If it exceeds 10.0 μm, the dispersion stability becomes poor, which is not preferable.

The self-dispersible water-based polyester resin of the present invention is impregnated into woven fabric, nonwoven fabric, paper, wood, leather, rubber, plastic, metal, glass, concrete, gypsum, ceramic siding material, ALC plate, or the like. By applying to these surfaces, surface coating, adhesion,
In addition to the effect of improving properties such as texture improvement, filming liquid for cathode ray tubes, bar code labels (P
It can be advantageously used in fields where coating agents for OS labels, civil engineering and construction, inks, paints, powder emulsions, and rubber latex and resin emulsions are generally applied. Further, since it is a polymer surfactant in terms of structure, it has a wide range of uses as a general surfactant in addition to its use as a binder. For example, there are uses such as protective colloids for emulsion polymerization, dispersants such as coal and calcium carbonate, flocculants, binders, and surface modifiers.

Among these uses, it was found that the self-dispersion type aqueous polyester resin was particularly effective as a paper surface treating agent. That is, by applying the self-dispersible water-based polyester resin of the present invention to the surface of thermal transfer paper (transfer paper) used in a plain paper copier, a plain paper printer, etc., the fixing strength between the toner or the thermal transfer ink and the paper is improved. It can be improved.

The method for treating the surface of paper using the composition for surface treatment of paper of the present invention can be performed, for example, by applying a coating temperature, a coating pressure, a coating amount, and a coating amount to a base paper using a blade coater or the like. The coating may be performed by appropriately adjusting the speed and the like, and then drying using a drier or the like.

[0026]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but it is needless to say that the present invention is not limited to these examples. Note that all “parts” and “%” below are based on weight unless otherwise specified.

Production Example 1 (Production of polyester resin) Polyoxypropylene (2.2) -2,2-bis (4-
(Hydroxyphenyl) propane (1050 g), fumaric acid (340 g), and hydroquinone (1.5 g) were placed in a glass 2-liter four-necked flask, and a thermometer, a stainless steel stirring rod, a falling condenser, and a nitrogen inlet tube were attached.
The reaction was carried out while stirring at 210 ° C. under a nitrogen stream in a mantle heater. The degree of polymerization is ASTM E28-5.
Tracking is performed from the softening point according to 1T, and the softening point is 100 ° C.
When the reaction reached, the reaction was terminated. The obtained resin was a pale yellow solid, and the glass transition temperature by DSC was 61.5 ° C. The acid value of the resin (measured by a method according to JIS K 0070) was 21.5 KOH mg / g, and the number average molecular weight (in terms of polystyrene by gel permeation chromatography) was 3,500. The polyester resin is referred to as polyester resin A.

Production Example 2 (Production of polyester resin) Polyoxypropylene (2.2) -2,2-bis (4-
(Hydroxyphenyl) propane 716 g, 1,4-butanediol 12 g, trimethylolpropane 72 g, fumaric acid 278 g, isododecenyl succinic acid 127 g,
The reaction was carried out using 1.5 g of hydroquinone and the same apparatus and procedure as in Production Example 1. When the softening point reached 120 ° C., the reaction was terminated. The obtained resin was a light yellow solid, and the glass transition temperature by DSC was 65.0 ° C. The acid value of the resin was 12.0 KOH mg / g, and the number average molecular weight was 4,000. The polyester resin is referred to as polyester resin B.

Example 1 300 parts of methyl ethyl ketone was put into a reactor equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer and a nitrogen inlet tube, and the polyester resin A obtained in Production Example 1 was added and dissolved at room temperature. I let it. The above polyester solution was neutralized by adding 2.7 parts of triethylamine, and then deionized water 1 was added.
After adding 000 parts, under reduced pressure at a stirring speed of 250 rpm,
Methyl ethyl ketone was distilled off at 50 ° C. or lower to obtain a self-dispersible aqueous polyester resin (1) of the present invention. The average particle size was 0.9 μm. Particle size is COULTER EL
COULTER MODEL manufactured by ECTRONICS
Measured at N4.

Example 2 Using 50 parts of the polyester resin B obtained in Production Example 2,
Using 300 parts of methyl ethyl ketone, 10 parts of a 10% aqueous sodium hydroxide solution for neutralization, and 1,000 parts of ion-exchanged water, the same operation as in Example 1 was carried out, and the self-dispersible water-based polyester resin (2) of the present invention was used. I got The average particle size was 0.5 μm.

Test Example After preparing a base paper according to the following procedure (1), a surface treating agent composition for paper was applied thereto according to the following procedure (2) to prepare a neutral electrophotographic transfer paper. A toner fixing test was conducted using a commercially available copying machine in the manner described in (3). (1) Preparation of base paper Base paper was prepared using the following raw materials in the amounts described. Pulp: 400 ml of LBKP (Canadian Standard Freeness) Filler: light calcium carbonate (commercially available) adjusted to 8% calcium carbonate in paper Fixing agent: cationic starch (commercially available), solid based on pulp weight 0.5% min. Sizing agent: Ketene dimer sizing agent (Silyne S9
4, manufactured by Kao), solid content 0.03% based on pulp weight Yield improver: cationic polyacrylamide polymer (commercially available), addition of raw material having solid content 0.02% or more based on pulp weight Pulp, filler, fixing agent, sizing agent, and retention aid were performed in this order. The pH at the time of fixing was 8.0. Papermaking uses a TAPPI square type hand paper making machine, the press was carried out for 2 minutes at 3.5kgw / cm ^2, drying was carried out for 40 seconds at 100 ° C. in a rotary drier, a basis in calendering linear pressure is 30kg / cm ² A base paper having an amount of 70 g / m ² was prepared. The basis weight of the base paper thus obtained is 70 g /
m ² . (2) Coating Using the base paper obtained above, using a blade coater, a coating temperature of 70 ° C. and a coating pressure of 0.3 to 0.4 kg / c.
The paper surface treating agent composition was applied at m ² and a coating speed of 100 m / min so that the coating amount of the paper surface treating agent shown in Table 1 was as shown in the table. Thereafter, using a rotary dryer, 10
It dried at 5 degreeC and 40 second, and produced the transfer paper for neutral electrophotography (coating paper-). Here, a paper surface treatment composition composed of oxidized starch was used for the coated paper for comparison. The coated papers used were the self-dispersible aqueous polyester resins (1) and (2) obtained in the above Examples.

[0032]

[Table 1]

(3) Fixing test The rotational speed of the fixing roller was set to 2 using a commercially available electrophotographic copying machine.
55 mm / sec, the temperature of the heat roller in the fixing device was varied, and the oil coating device was removed, and the paper coated with only the oxidized starch (coated paper), a self-dispersible water-based polyester resin other than the oxidized starch was used. Coated paper (coated paper ~
), And an image was formed using genuine toner. The fixing temperature was controlled at 100 ° C. to 220 ° C., and the fixing property and offset property of the image were evaluated. Table 2 shows the results.

[0034]

[Table 2]

Here, the minimum fixing temperature is 15 m
A 500 g load is placed on a sand eraser mx 7.5 mm,
The image fixed through the fixing device was rubbed five times back and forth, and before and after the rubbing, the optical reflection density was measured with a reflection densitometer manufactured by Macbeth. Refers to temperature. Fixing rate = image density after rubbing / image density before rubbing × 10
0

As is apparent from Table 2, paper coated with the self-dispersible water-based polyester resin of the present invention can lower the minimum fixing temperature for copiers as compared with paper not coated. Further, the coated paper is subjected to high temperature and high humidity (3
The paper did not bend even when left for 1 day under the conditions of 5 ° C. and 85% RH).

[0037]

According to the present invention, a polyester resin having a predetermined acid value is ionized in a ketone-based solvent, the solvent is distilled off, and the phase is changed to an aqueous phase. A dispersion type aqueous polyester resin can be obtained. Further, by using the self-dispersible aqueous polyester resin, a paper surface treating composition which can improve the low-temperature fixability of the toner can be provided.

Claims (5)

(57) [Claims] (1) A diol component represented by the following formula: (Wherein, R represents an ethylene or propylene group, x, y
Is an integer of 1 or more, respectively, and the average value of x + y is 2 to 7. (B) at least one alcohol component selected from the group consisting of (b) aliphatic diols and (c) trihydric or higher polyhydric alcohols; and (d) dihydric carboxylic acids, acid anhydrides or lower alkyl esters thereof. And (e) an acid value obtained by copolycondensation of at least one acid component selected from the group consisting of a trivalent or higher polycarboxylic acid, an acid anhydride thereof, and a lower alkyl ester thereof, from 3 to 70K.
OH mg / g polyester resin is dissolved in a ketone solvent, a neutralizing agent is added to ionize the carboxyl group of the polyester resin, and then water is added. A self-dispersible water-based polyester resin composition . 2. The polyester resin used for phase inversion is 25
The self-dispersible water-based polyester resin composition according to claim 1, which has a glass transition temperature of not less than ° C. (A) a diol component represented by the following formula: (Wherein, R represents an ethylene or propylene group, x, y
Is an integer of 1 or more, respectively, and the average value of x + y is 2 to 7. (B) at least one alcohol component selected from the group consisting of (b) aliphatic diols and (c) trihydric or higher polyhydric alcohols; and (d) dihydric carboxylic acids, acid anhydrides or lower alkyl esters thereof. And (e) an acid value obtained by copolycondensation of at least one acid component selected from the group consisting of a trivalent or higher polycarboxylic acid, an acid anhydride thereof, and a lower alkyl ester thereof, from 3 to 70K.
OH mg / g polyester resin is dissolved in a ketone solvent, a neutralizing agent is added to ionize the carboxyl group of the polyester resin, and then water is added. A method for producing a self-dispersible aqueous polyester resin composition, comprising : 4. The polyester resin used for phase inversion is 25
The method for producing a self-dispersible water-based polyester resin composition according to claim 3 , which has a glass transition temperature of not less than ° C. 5. A paper surface treating agent composition comprising the self-dispersible aqueous polyester resin composition according to claim 1 or 2 as a component of the paper surface treating agent.