JPS605475B2 - pressure sensitive recording paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure-sensitive recording paper, and is particularly characterized in that acid-modified polyolefin particles are dispersed in a microcapsule coating layer.

In general, pressure-sensitive recording paper consists of an upper paper (CB paper) in which microcapsules containing minute oil droplets containing an electron-donating organic coloring agent are coated on one side of a supporting substrate, and an electron-accepting coloring agent is coated on one side of the supporting substrate. A set of base paper (CF paper) coated on one side is stacked so that each coated side faces each other, and the capsule is destroyed by processing such as using a typewriter or writing, and the coloring agent inside is converted into a star coloring agent. Transfer and react to obtain a duplicate image.

In order to obtain a larger number of copies, one side of the supporting substrate is coated with the microcapsules, and the other side is coated with the coloring agent (CFB).
In practice, a desired number of sheets of paper (paper) are inserted between the upper and lower sheets. In addition, pressure-sensitive recording paper (self-contained paper) in which microcapsules and a coloring agent are coated on the same surface of a support substrate in two layers or in a mixed manner has been put into practical use.

One of the important properties required of such pressure-sensitive recording paper is that it is capable of producing clear, high-density colored images during copying,
One example of this is that unnecessary colored stains do not occur during manufacturing, secondary processing, printing, storage, etc.

In order to satisfy these required characteristics, microcapsules must have practical mechanical strength such as pressure resistance, abrasion resistance, and impact resistance. It is not possible to obtain a pressure-sensitive recording paper that simultaneously satisfies the contradictory characteristics of having to develop color efficiently, having a high color development capacity, and being resistant to staining. In general, the pressure required to destroy a microcapsule is inversely proportional to its particle diameter, so the color development caused by the capsule destruction due to strong pressure such as typewriter, writing, etc., does not deteriorate when the particle size of the microcapsule is produced. Many efforts have been made to improve color stains caused by low pressure that occur during secondary processing, printing, storage, etc., but mononuclear capsules or U.S. Pat.
Even with the polynuclear capsules proposed in No. 0y, it is extremely difficult to have the same particle size on average, so the particle size distribution spreads over a wide range, and as a result, the capsules are destroyed by a wide range of pressure, resulting in virtually no damage. It has not yet been possible to satisfactorily improve unnecessary coloring stains without reducing coloring properties.

In view of the current situation, the object of the present invention is to have high coloring ability, especially excellent low-pressure coloring ability, and to maintain excellent pressure resistance and abrasion resistance when handling other than the original use of recording paper, thereby eliminating unnecessary An object of the present invention is to provide pressure-sensitive recording paper that does not cause colored stains.

The object of the present invention is to provide an acidic acid having a volume average particle size of 1/5 to 2.5 times the volume average particle size of the microcapsules and an acid value of 1 or less in the microcapsule coating layer of the pressure-sensitive recording paper. This is achieved by dispersing modified polyolefin particles.

In the present invention, the denature-modified polyolefin particles are particles containing a base, preferably a carboxyl group, in the polyolefin particles, for example, '1} Acid-modified polyolefin particles containing an acid group in the molecule {2) (1) above Examples include composition particles obtained by mixing an acid-modified polyolefin and a base polyolefin.

Furthermore, to explain the acid-modified polyolefin particles, as the acid-modified polyolefin containing an acid group in the molecule, for example, a copolymer of an olefin monomer or polymer and a monomer or polymer containing an ethylenically unsaturated acid or its derivative is used. products, oxidized products of base polyolefins, and acid adducts obtained by heating base polyolefins and ethylenically unsaturated acids or derivatives thereof in a nitrogen atmosphere in the presence of a solvent and a radical initiator as necessary. can be given. The olefin monomers used in producing the acid-modified polyolefin include ethylene hydrocarbons such as ethylene, propylene, butene, bentene, methylbutene, methylbentene, hexene, dimethylbutene, heptene, ochene, nonene, and decene. Ethylene has low hardness;
It is preferably used because particles with high flexibility are formed.

In addition, the olefin polymer and base polyolefin for obtaining the above-mentioned copolymer are prepared by subjecting one or more of the above-mentioned olefin monomers or, if necessary, a vinyl monomer copolymerizable with these monomers to high pressure in the presence of a molecular weight regulator such as hydrogen. It can be obtained by polymerization by a known method such as a method, a medium pressure method, or a low pressure method. Examples of ethylenically unsaturated acids include monobasic acids having 2 to 8 carbon atoms such as acrylic acid, methacrylic acid, crotonic acid, vinylsulfonic acid, and their derivatives: maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid. In addition to dibasic acids having 4 to 11 carbon atoms such as , glutaconic acid, and 5-norbornene-2,3-dicarboxylic acid and derivatives thereof, monoesters, monoamides, and monohalides thereof are exemplified.

In addition, examples of the above-mentioned derivatives include acid anhydrides, acid halides, amides, and imide salts.

In order to produce the acid-modified polyolefin composition used in the present invention by mixing an acid-modified polyolefin containing an acid group in the molecule with a base polyolefin, the mixture is heated at a temperature above the melting point of the polyolefin and within a range where the polyolefin is not oxidized. They may be melted by heating and mixed, or mixed and dissolved in the presence of an organic solvent. At that time, a surfactant suitable for oil-in-water type dispersion may be added, if necessary, within a range that does not reduce the effects of the present invention. In the present invention, what is important in producing such acid-modified polyolefins and acid-modified polyolefin compositions is the degree of acid modification.

The acid-modified polyolefin particles used in the present invention significantly improve the color development properties of pressure-sensitive recording paper, especially the low-pressure color development property, pressure resistance, and abrasion resistance, but excessive acid modification increases the surface activity of the polyolefin. Otherwise, the heat resistance and sea resistance of the capsule will decrease. Therefore, during acid modification, the acid-modified polyolefin particles must be modified so that the acid value of the obtained acid-modified polyolefin particles is 1 or less. Generally, acid value is one of the characteristics of oils and waxes, and 1g of oils and waxes
It is defined as the number of KOH particles required to neutralize the free fatty acids contained therein, and the acid value in the present invention is defined as the number of KOH particles required to neutralize 1 g of acid-modified polyolefin particles. expressed. On the other hand, if the acid value is too low and falls within the measurement error, it may be calculated from the blending ratio. Next, the acid-modified polyolefin and the composition obtained by mixing the acid-modified polyolefin and the base polyolefin are mechanically treated, or a solution of these dissolved in an organic solvent is stably dispersed in water using an appropriate mixing device and a dispersion stabilizer. The volume average particle size of the resulting fine particles is one of the volume average particle size of mononuclear or polynuclear microcapsules. If the pressure resistance is 4.5 times larger than /5, and if it is larger than 2.5 times, the desired improvement effect in abrasion resistance and color development cannot be obtained, so it depends on the volume average particle diameter of the applied microcapsule Therefore, it is necessary to micronize the particles to have a volume average particle diameter of 1/5 to 2.5 times that amount.

Note that the volume average particle diameter described in the present invention is a volume distribution measured with a Coal-Router counter, and indicates a particle diameter value where the cumulative volume value accounts for 50% of the total. In the present invention, the acid-modified polyolefin particles need to have the above-mentioned specific volume average particle diameter, but even if they have such a specific volume average particle diameter, particles with a particle diameter of one peak or less have surface activity. It is preferable that the volume ratio does not exceed 20%, more preferably 5%, because it has a strong tendency to reduce the stability of capsule strength, specifically, the heat resistance and moisture resistance of the capsule. In addition, particles with a size of 5 or more tend to reduce color development and deteriorate abrasion resistance, so they also have a volume ratio of 20%,
More preferably, it does not exceed 5%. The acid-modified polyolefin particles thus obtained can be used as an aqueous dispersion or as a dry powder.

It is added and blended into the capsule dispersion. The blending amount varies depending on the particle size of the acid-modified polyolefin particles, the size of the capsule, the amount of coating, etc., and is not critical, but if it is dispersed in too large a amount in the capsule coating layer, the coloring performance will deteriorate. Also, if the amount is small, it becomes difficult to expect the desired improvement effects on pressure resistance, abrasion resistance, etc. Therefore, the amount of acid-modified polyolefin particles dispersed in the capsule coating layer varies depending on various factors such as capsule particle size, strength, coating amount, etc., and is not uniform. For 100 parts by weight of microcapsules having a particle size, at least 5 parts by weight or more is used, and the upper limit is appropriately controlled in relation to coloring performance, but is approximately 10 parts by weight or less. In addition, in the pressure-sensitive recording paper of the present invention, in addition to the acid-modified polyolefin particles as detailed above, the capsule coating layer contains binders and stilts that are conventionally used in the production of pressure-sensitive recording papers. Appropriate amounts of various materials such as agents can also be included.

Examples of the binder include latexes such as styrene-phthalene latex, acrylic ester latex, and vinyl acetate latex, proteins such as casein and gelatin, and cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose. For example, sodium alginate, gum arabic, etherified starch, oxidized starch, cationic starch, etc., polyvinyl alcohol, polyacrylic acid, polyacrylic acid amide, or styrene-maleic anhydride copolymer, styrene-acrylic acid copolymer. Water-soluble or water-soluble salts (sodium salts, potassium salts, ammonium salts, etc.) of binary or multicomponent copolymers of styrene and ethylenically unsaturated carboxylic acids such as styrene-methacrylic acid copolymers, etc. Examples include water-dispersible binders, and among these, water-soluble polymer binders are particularly effective in stably dispersing acid-modified polyolefin particles with a relatively light specific gravity into the microcapsule coating liquid for a long time. In particular, hydroxyethylcellulose exhibits excellent effects when used together with acid-modified polyethylene particles. Furthermore, the ammonium salt of the binary or multicomponent of styrene and ethylenically unsaturated carboxylic acid is effective in preventing unnecessary surface activity of the acid-modified polyolefin particles of the present invention and maintaining the moisture resistance and heat resistance of the capsule. It acts in a certain way.

Examples of the stilting agent include cellulose fine powder, starch particles; particles obtained by hardening and drying gelatinized starch and pulverizing them; polymer particles such as styrene, vinyl chloride, vinyl acetate, etc.; glass beads; microspheres, etc. In particular, cellulose fine powder is preferably used together with the acid-modified polyolefin particles of the present invention.

In addition, a surfactant may be added as appropriate within a range that does not reduce the quality of the capsule, such as moisture resistance and heat resistance.

In the present invention, the capsule manufacturing technology itself is not particularly limited, and any encapsulation technology that can be used for pressure-sensitive recording paper can be used, such as those disclosed in U.S. Pat. No. 3,789,015. , 37692
31, 3687865, and 2800457, in which a concentrated phase of the polymer is phase-separated from an aqueous solution of the polymer to form a capsule wall; for example, British Patent Nos. 104640 and 9
No. 50443, Special Publication No. 44-11772, No. 42-2
An interfacial polymerization method in which a hydrophobic monomer and a hydrophilic monomer are combined as described in Japanese Patent Publication No. 883, and a capsule wall is formed using an interfacial polymerization reaction at the interface of emulsified oil droplets; for example, Japanese Patent Publication No. 38-19574, No. 36-13412, No. 3
6-9168, an in situ polymerization method in which monomers and polymerization catalysts are supplied only from either the inside or outside of emulsified oil droplets, and a polymerization reaction occurs on the surface of the emulsified oil droplets to form a capsule wall. Examples include.

Among these encapsulation techniques, the coacervation method is well known as the most commonly employed technique and is preferably used with koji. In addition, in the present invention, there are no particular limitations on the oil-based substance and organic coloring agent contained in the microcapsules, or the coloring agent that can develop color upon contact with the organic coloring agent, and conventional pressure-sensitive recording Any material employed in paper can be used.

EXAMPLES The present invention will be described in more detail by way of Examples below, but the technical scope of the present invention is of course not limited to these Examples.

In addition, in the following examples, unless otherwise specified, the amount of each component indicates parts by weight.

Example 1 A base portion of polyethylene 20 having a molecular weight of 4000 was heated and melted at 170 qo in a nitrogen atmosphere, and 1.5 parts of Nada Yoshita ditertiary butyl peroxide and 0.0 parts of heated and melted maleic anhydride were added to this. Cellulose was added dropwise and reacted at 170 qo for 1 hour.

After the reaction was completed, the pressure was reduced to 5 Hg at the same temperature and held for an additional 1 hour to remove volatile components such as unreacted maleic anhydride and peroxide decomposition products, and the mixture was transferred to a magnetic dish and solidified. The acid value of this product was 0.8. This was further melted and dropped into hot water at 95° C. while cooling, and an aqueous dispersion of carboxy-modified polyethylene particles was obtained. This aqueous dispersion was classified to obtain an aqueous dispersion having a volume average particle diameter of 1 tsubo and particles having particle diameters of 1 tsubo or less and 5 tsubo or more in volume ratios of 1% and 0%, respectively. Separately, a capsule dispersion was prepared as follows.

That is, 25 parts of acid-treated gelatin (isoelectric point 8) in 225 parts of water.
After 1 hour of standing at 100°C, 23 miyako water was added to dissolve the gelatin at 60°C. To this gelatin solution, 60 qo of a solution consisting of 3 parts of kerosene and 7 parts of inpropyl naphthalene in which 2 parts of crystal violet lactone and 1 part of penzoyl leucomethylene blue were dissolved in advance was added. It was emulsified and dispersed so that the volume average particle size became oil droplets of 6.5%.Separately, a 5% aqueous solution of carboxymethylcellulose was prepared, and 50 parts of it was added to the emulsion while stirring.
After adjusting H to 5.5, cool to 10℃ and reduce to 15%.
One glutaraldehyde aqueous solution was added and the mixture was allowed to stand for 5 minutes, and the pH of the system was adjusted to 9 with a 10% caustic soda aqueous solution to prepare a mononuclear capsule dispersion having a uniform particle size distribution. The above-mentioned aqueous dispersion of acid-modified polyethylene particles was added to the capsule dispersion in amounts of 5, 10, 20, and 3 parts by solid weight, and sufficiently coagulated and dispersed.

The capsule dispersion thus obtained was coated on the other side of the inner sheet, which had been coated with a star coloring agent on one side, to a dry coating amount of 5 g, and dried. The above-mentioned inner paper was prepared as follows.

15 parts of Q-methylstyrene polymer (average molecular weight 1100, softening point 110 qo) was heated and melted to 180 qo, and 45 parts of zinc salt of 3.5-di(Q,Q-dimethylbenzyl)salicylic acid was added thereto. Dissolved and mixed. This was cooled and solidified, then crushed, mixed with 300 parts of water, and 10 parts of sodium butylnaphthalene sulfonate (Verex NBL, manufactured by Kao Atlas Co., Ltd.) and 250 parts of a 10% aqueous solution of polypynyl alcohol. The suspension thus obtained, pulverized in a continuous sand grinder, was mixed with 180 parts of aluminum hydroxide, 60 parts of kaolin, 200 parts of a 10% soluble starch aqueous solution and a styrene-butadiene copolymer latex with a solids content of 50%. A coating liquid was obtained by adding 50$ of chlorine and mixing it with the fly azusa. This coating liquid was continuously coated on one side of a base paper of 40 g per square meter in a dry weight of 6 g/m2 using a blade coater and dried to obtain an inner paper. In order to confirm the effects of the present invention, the following various quality tests were conducted, and the results are shown in Table 1.

Note that quality tests were similarly conducted for other Examples and Comparative Examples. 1 Chromogenicity and Kuttei Pressure Chromogenicity Nine sheets of inner paper were stacked so that the capsule-coated side and the star coloring agent-coated side faced each other, and a weight of 20 pieces was applied linearly at three skin intervals to form a colored linear image group. I got it.

The coloring density of the coloring agent coated surface of the 2nd and 9th sheets from the top,
After 24 hours had elapsed after color development, the reflectance (%) at 61 hours was measured using a spectrophotometer (12 Sakojuku, Hitachi Double Beam Spectrophotometer), and the color development and low pressure color development were determined, respectively. It should be noted that the smaller the reflectance value, the higher the color density, which is a preferable tendency. 2 Pressure Resistance Layer two sheets of inner paper so that the capsule-coated side and the coloring agent-coated side face each other, apply a weight of 30k9/base to form a coloring mark on the coloring agent-coated side, and adjust the coloring density to the above. Measurements were made in the same manner.

In this case, the larger the reflectance value is, the stronger the pressure resistance is, and the less unnecessary colored stains are produced, indicating a favorable tendency. 3
Friction Resistance Using a Sutherland friction tester, the capsule-coated side and coloring agent-coated side of the inner paper were brought into contact with each other so that they faced each other under a load of 0.13 lbs., and the star coloring agent was applied by rubbing back and forth 5 times. A colored mark was formed on the surface, and the color density was measured in the same manner.

In this case as well, there is a preferable tendency that the larger the reflectance value is, the stronger the abrasion resistance is. 4 Weaving resistance Layer two sheets of inner paper so that the capsule-coated side and the coloring agent-coated side face each other, and leave them at 50°C and 90% RH under 3 female/ball pressure for 7 hours to apply the star coloring agent. Visually observe the state of colored stains on the coated surface.

5. Heat Resistance Two sheets of inner paper are stacked in the same manner as in the spill resistance test, and the paper is left under pressure at 115° C. for 5 hours, and colored stains on the surface coated with the coloring agent are observed in the same manner.

Example 2 25 parts of acid-treated gelatin was added to 225 parts of water, left for 1 hour at 1ooC, and then 23 parts of water was added to make 60qo.
The gelatin was dissolved.

To this gelatin solution, a solution consisting of 3 parts of kerosene and 7 parts of imbropyl naphthalene in which 2 parts of crystal violet lactone and 1 part of penzoyl leucomethylene blue had been dissolved in advance was added to 60 oz. The oil was emulsified and dispersed to form oil droplets with a volume average particle diameter of 2.5 mm.
Separately, a 5% aqueous solution of carboxymethyl cellulose was prepared, and 5 parts of it were added to the emulsion while stirring.Then, after adjusting the pH to 5.0, the mixture was slowly heated to 10°C. did. Next, 1 part of a 15% glutaraldehyde aqueous solution was added and left to stand for 5 minutes, and then a 10% caustic soda aqueous solution was added dropwise to adjust the spotness of the system to 9. The microcapsule dispersion thus obtained has a volume average particle diameter of 9. It was a polynuclear capsule dispersion of &. 20 parts by solid weight of the acid-modified polyethylene particle dispersion obtained in Example 1 was added to 643 parts of this capsule dispersion, thoroughly mixed and dispersed, and the capsule dispersion was coated and dried in the same manner as in Example 1. Inner paper was prepared using the same method, and quality tests were conducted in the same manner. Example 3 The same method as in Example 1 was used except that polyethylene with a molecular weight of 10,000 was used, and the reaction time and dehydration conditions were changed.
Particles with a particle size larger than 5% by volume each
and 0% aqueous dispersion of carboxy-modified polyethylene particles was obtained.

3 parts of this aqueous dispersion by solid weight were added to 643 parts of the capsule dispersion obtained in Example 2, mixed and dispersed well, and this capsule dispersion was coated and dried in the same manner as in Example 1 to form inner paper. We created and conducted quality tests. Example 4 300 anchor parts of polyethylene with an acid value of 0 and 0.1 part of acid-modified polyethylene with an acid value of 1
1 part and 0.1 part of sodium alkylbenzenesulfonate were melted together at 130 o'clock for 30 minutes under lighting to obtain a polyethylene composition.

30 parts of this polyethylene composition was placed in an autoclave together with 500 parts of hexane and 850 parts of water at 130°C.
The system was run at high speed for 10 minutes, and then the loss speed was reduced and the temperature of the entire system was cooled to 40°C. Next, hexane was distilled off, the same overtreatment as in Example 1 was carried out, and the volume average particle diameter was 6.
．． An aqueous dispersion of polyethylene particles was obtained in which the volume proportions of particles having particle diameters of 1 tsubo or less and 5 tsubo or more were 3% and 0%, respectively. An inner paper was prepared in the same manner as in Example 2 except that this aqueous dispersion of polyethylene particles was used, and a quality test was conducted. Example 5 Using polypropylene instead of polyethylene, volume average particles were prepared by using the same method as in Example 1.
The volume ratio of particles less than or equal to 50 and more than 50 are both 0.
% of acid-modified polypropylene particles was obtained.

An inner sheet was prepared using the same machine as in Example 2, except that this aqueous polypropylene dispersion was used, and an L quality test was conducted. Example 6 The same procedure as in Example 1 was carried out except that ethylene-vinyl acetate copolymer (ethylene 8 vinyl triacetate 2) was used instead of polyethylene.
The constitution ratio of particles of 1 or less and 5 or more are both 1
% of carboxy-modified ethylene, vinyl acetate copolymer particles was obtained.

Inner paper was prepared in the same manner as in Example 2, except that this dispersion was used, and a quality test was conducted. 1 part of vinyl copolymer to 130q
The mixture was melted and mixed for 30 minutes at a temperature of 30°C to obtain a composition.

The same procedure as in Example 4 was carried out except that this composition was used as the polyethylene composition, and the volume ratios of particles with volume average particle diameters of 7 French, 1 French or less, and 5 French or more were 5% and 0%, respectively.
A dispersion of particles was obtained. An inner paper was prepared in the same manner as in Example 2 except that this dispersion was used, and a quality test was conducted. Example 8 In Example 3, instead of adding 3 parts of carboxy-modified polyethylene particles by solid content weight, 2 parts of carboxy-modified polyethylene particles were added, and 2 parts of pulp powder (W-300 manufactured by Sanyo Kokusaku Pulp) was added and mixed. A capsule dispersion was prepared, and an inner paper was prepared in the same manner as in Example 3, except that this dispersion was used, and a quality test was conducted.

Example 9 Example 8 except that 4 parts of a 5% hydroxyethylcellulose aqueous solution was used instead of 2 parts of pulp powder.
Inner paper was prepared in the same manner as above, and a quality test was conducted.

Note that this capsule dispersion showed no tendency for the polyethylene particles to separate even after standing for 5 hours, and was an extremely stable dispersion. Example 10 Insert paper was prepared in the same manner as in Example 2, except that an ammonium salt of a styrene-acrylic acid copolymer having a weight of 2 solids was added to the microcapsule dispersion before being applied to the inner paper. Created and quality tested.

Example 11 The same procedure as in Example 10 was carried out except that an ammonium salt of a styrene-maleic anhydride copolymer was used instead of an ammonium salt of a styrene-acrylic acid copolymer.

Comparative Example 1 Instead of acid-modified polyethylene particles, molecular weight 4000,
In the same manner as in Example 1, using non-acid-modified polyethylene particles, the volume ratio of particles with volume average particle diameters of 1, 1, 1, and 50 or more was 1% and 5%, respectively. A paper was created and a quality test was conducted.

Comparative Example 2 The amount of maleic anhydride added was 0. Carboxy modification was carried out in the same manner as in Example 1, except that 0.5 part was used instead of Moribe, with an acid value of 2, a volume average particle diameter of 1, and particles with a volume ratio of less than 1R and 50 or more having a volume ratio of 0%. An aqueous dispersion of polyethylene particles was obtained.

To 643 parts of the capsule dispersion obtained in Example 1 was added the aqueous dispersion of the above-mentioned polyethylene particles of 2 fat B in terms of solid content, and the mixture was thoroughly stirred. Using the capsule dispersion thus obtained, inner paper was prepared in the same manner as in Example 1, and a quality test was conducted. Comparative Example 3 Example 1 except that the amount of maleic anhydride added was 2.5 parts
The same machine has an oxidation rate of 10 and a volume average particle size of 6. In autumn, the volume ratio of particles below 1〆 and particles above 5OA is 3% each.
An aqueous dispersion of carboxy-modified polyethylene particles having a concentration of 0% and 0% was obtained.

Inner paper was prepared using the same machine as in Example 2, except that this aqueous dispersion was used, and a quality test was conducted. Comparative Example 4 The same procedure as in Example 1 was carried out except that the filtration conditions were changed, and the volume ratios of particles with an acid value of 0.8 and a volume average particle diameter of 2 or less, 1r or less, and 5 or more were 0% and 23%, respectively. An aqueous dispersion of carboxy-modified polyethylene particles was obtained.

Inner paper was prepared using the same machine as in Example 2, except that this aqueous dispersion was used, and a quality test was conducted. Comparative Example 5 Acid value 0.
8 Volume average particle diameter 3. An aqueous dispersion of carboxy-modified polyethylene particles was obtained in which the volume proportions of particles of 1 French or less and 50 French or more were 22% and 0%, respectively.

An inner paper was prepared in the same manner as in Example 2 except that this aqueous dispersion was used, and a quality test was conducted. Comparative Example 6 Starch particles with a volume average particle diameter of 30 mm (manufactured by Oji Cornstarch Co., Ltd., Ace E
) Inner paper was prepared in the same manner as in Example 2, except that 2 parts of Ikarito and 2 parts of gelatinized starch were used, and a quality test was conducted.

Comparative Example 7 Acid-modified polyethylene particles 2 Pulp powder (
Inner paper was prepared in the same manner as in Example 2, except that W-300 (manufactured by Sanyo Kokusaku Pulp Co., Ltd.) 2 Ikari-gun and gelatinized starch 2 Ikari-to were used, and a quality test was conducted.

As is clear from the results in Table 1, each example of the present invention has high coloring ability when used as a recording paper, and maintains excellent pressure resistance, abrasion resistance, moisture resistance, and heat resistance during handling. Pressure-sensitive recording paper with a well-balanced quality that does not cause unnecessary colored stains was obtained. Example 1
2. Dissolve 2 parts of crystal violet lactone and 1 part of penzoylleucomethylene blue in 9 parts of diisopropylnaphthalene, and add trimethylolproban adduct of tolylene diisocyanate (trade name Coronate L, Japan) to this oily liquid. Polyurethane Co., Ltd.) 2 anchors and 1 anchor of dimethyl phthalate as an auxiliary solvent were added and dissolved.

This oily liquid is mixed with polyvinyl alcohol (product name: PVA-2).
17 (manufactured by Kuraray Co., Ltd.) was emulsified in 200 parts of a 5% aqueous solution using a homomixer to obtain a dispersion of average particle Mogo 9 Butsu.

Diethylenetriamine 1, which is a polyvalent amine, is added to this dispersion.
．． After adding Soho and lighting one powder at room temperature, the temperature of the system was raised to 75°C and reacted for 3 hours, and further cooled to room temperature to obtain a color former-containing microcapsule dispersion. . Separately from the above microcapsule dispersion, a color former dispersion was prepared as follows.

60 parts of a styrene polymer having a melting point of 12,100 was heated and dissolved to 180 qo, and 10 parts of a zinc salt of 3,5-di(Q-methylbenzyl)salicylic acid were dissolved and mixed therein. This is cooled and solidified, and then coarsely crushed to obtain sodium butylnaphthalene sulfonate (trade name: Verex NBL, manufactured by Kao Atlas Co., Ltd.) 1
The mixture was dispersed in 50 parts of water to which 25 parts of a 10% aqueous solution of polyvinyl alcohol had been added, and finely processed using a continuous sand grinder. Further, 40 parts of finely powdered zinc silicate, 10 parts of kaolin, 200 parts of a 10% oxidized starch aqueous solution and 20 parts of water were added to this dispersion, and after stirring thoroughly, the carboxy-modified styrene/putadiene copolymer was added. Five parts of latex (solid content 50%) were added and mixed to obtain a coloring agent dispersion.

100 parts of the above color former-containing microcapsule dispersion (in terms of solid content), 100 parts of the color former dispersion (in terms of solid content), 2 starch particles, and 100 parts of the acid-modified polyethylene particles obtained in Example 1 of the present invention. parts (in terms of solid content) were mixed to obtain a uniform single coating liquid.

This single coating solution was continuously coated on one side of base paper with a dry weight of 10 g using an air knife coater to obtain a single pressure-sensitive recording paper in the form of a single layer. .

Comparative Example 8 The procedure was carried out as in Example 12, except that 12 parts of Kawayuko starch particles of "2 parts of starch particles and 10 parts of acid-modified polyethylene particles (in terms of solid content)" in Example 12 were used, and a single layer was formed. A coating liquid for single-piece pressure-sensitive recording paper was obtained.

Apply this coating liquid at a dry weight of 1 on one side of base paper of 4 m2/m2 size.
The coating was applied continuously using an air knife coater so as to cover the thighs and eyes to obtain a single-layer pressure-sensitive recording paper. Example 1
3. Dissolve 2 parts of crystal violet lactone and 1 part of benzoylleucomethylene blue in 9 parts of phenylxylyl ethane, and add a trimethylolpropane adduct of tolylene diisocyanate (trade name Coronate L, 15 parts (manufactured by Nippon Polyurethane Co., Ltd.) and 1 part of dioctyl phthalate as an auxiliary solvent were added and dissolved.

This oily liquid is mixed with polyvinyl alcohol (product name: PVA-2).
No. 17 (manufactured by Kuraray Co., Ltd.) was emulsified in 200 parts of a 5% aqueous solution using a homomixer to obtain a dispersion having an average particle size of 1. Triethylenetetramine 1, which is a polyvalent amine, is added to this dispersion.
．． After adding anchorage and stirring for 3 females at room temperature, the temperature of the system was raised to 8500°C, reacted for 5 hours, and further cooled to room temperature to obtain a color former-containing microcapsule dispersion. To 100 parts of this microcapsule dispersion (solid content equivalent),
A capsule coating liquid was obtained by adding 1 part of the valve powder, 3 parts (in terms of solid content) of the acid-modified polyethylene particles obtained in Example 1 of the present invention, and 3 parts of a 10% aqueous solution of starch particles.

This coating liquid was coated continuously on one side of four base papers using an air knife coater so that the dry weight was evenly distributed. Separately, 40 parts of water, 10 parts of activated clay, and 4 parts of sodium hydroxide were thoroughly dispersed, and 2 parts of carboxy-modified styrene-butadiene copolymer latex (solid content 50%) was added to this mixture.
Anchor part was added to obtain a coloring agent coating liquid.

Apply this coloring agent coating liquid on the capsule coating layer for 5 days/day by dry weight.
The film was coated continuously using an air knife coater to obtain a two-layer pressure-sensitive recording paper. Comparative Example 9 The same procedure as Example 13 was carried out except that 3 anchor parts of starch particles were used instead of 3 anchor parts of acid-modified polyethylene particles in Example 13, and the dry weight of the capsule coating solution was 5 g/, and the color former coating solution was A single pressure-sensitive recording paper with a dry weight of 1/2 layers was obtained.

The quality tests of the single pressure-sensitive recording papers obtained in Examples 12 and 13 and Comparative Examples 8 and 9 were carried out in accordance with the method used for the inner paper, and the results are shown in Table 1.

Table-1 (Note) *-1: The amount added indicates the amount (parts by solid weight) of polyolefin particles added to 100 parts by weight of oil in the microcapsule.

*-2: Judgment criteria were set to the following three levels.

Claims (1)

[Claims] 1. 1/5 to 2 of the volume average particle diameter of the microcapsules.
．． A pressure-sensitive recording paper characterized in that acid-modified polyolefin particles having a volume average particle diameter of 5 times as large and an acid value of 1 or less are dispersed in a microcapsule coating layer. 2. The pressure-sensitive recording paper according to claim 1, wherein the acid-modified polyolefin particles having particle diameters of 1 μm or less and 50 μm or more each account for less than 20% by volume. 3. The pressure-sensitive recording paper according to claim 1, wherein the acid-modified polyolefin contains an ethylenically unsaturated carboxylic acid or a derivative thereof in its molecule. 4. A composition according to claim 1, wherein the acid-modified polyolefin is a composition obtained by mixing an acid-modified polyolefin containing an ethylenically unsaturated carboxylic acid or a derivative thereof in the molecule and a base polyolefin. Pressure sensitive recording paper.