JPS6043316B2 - Developing paper for pressure-sensitive copying paper - Google Patents

Description

[Detailed description of the invention] The present invention relates to a color developer paper for pressure-sensitive copying paper.

More specifically, the present invention relates to an improved developer paper for pressure-sensitive copying paper that is excellent in color development, fading of colored images over time, ester properties, and yellowing of the developer paper due to ultraviolet rays.

Pressure-sensitive copying paper is described, for example, in U.S. Pat. No. 2,712,507, U.S. Pat.
No. 3,418,250, as has been known for a long time, microcapsules containing a nearly colorless solution of an organic compound; and an adsorbent substance that is colored by reacting with the coloring agent. (hereinafter referred to as a color developer). As the color developer, clays such as acid clay, activated clay, attapulgite, zeolite, and bentonite, organic compounds such as succinic acid, tannic acid, and gallic acid, or phenol resins are generally used.

Various forms of copy paper are known for producing a copy image by utilizing this color developing effect. For example, a pressure-sensitive material in which microcapsules made by encapsulating a nonvolatile oil containing an organic coloring agent dissolved therein by the coacervation method known in U.S. Pat. No. 2,800,457 is coated on one side of a base paper, and an acidic color developer is coated on the other side. Copy paper is known (U.S. Pat. No. 273
No. 0456). Then, when you stack several sheets of J with the coated sides facing each other and pressurize them by writing or typing, the microcapsules in the pressurized part are destroyed and the non-volatile oil that dissolves the organic color former becomes the acidic color developer. It transfers to the surface and develops color upon contact, resulting in a clear recorded image. Also, paper in which a coated layer of microcapsules and a coated layer of acidic head coloring agent are laminated on the same side of the base paper, or paper in which a uniform mixed paint of microcapsules and acidic color developer is coated on the same side of the base paper are so-called single coloring papers. known as.
Recently, polymers reactive with organic color formers such as phenol-aldehyde polymers, phenol-acetylene polymers, maleic acid-rosin resins, and hydrolyzed styrene-maleic anhydride copolymers have been used as acidic color developers. A pressure-sensitive copying paper has been introduced in which an organic coloring agent and at least one of the above polymers are separated from a solvent such as a non-volatile oil by a capsule membrane and distributed inside or on the surface of the base paper. The present invention is effectively utilized for various forms of pressure-sensitive copying paper as described above, and therefore, in the present invention, the term ``color developer paper for pressure-sensitive copying paper'' simply means that color is visible inside or on the surface of the base paper. It is not limited to those that contain only coloring agents, but also those that are contained together with coloring agents, oils, etc. inside or on the same base paper. It includes all sheets containing color substances. Conventional activated clay, acid clay, acidic clays such as attapulgite, organic acids or acidic polymers,
Or when producing color developing paper by combining these color developers,
It is known that yellowing of the developing paper itself due to ultraviolet rays, color development, fading of colored images, and ester resistance vary depending on other additives used in the mixture, such as dispersants, adhesives, fluidity improvers, and alkaline agents. ing.

The present inventors have arrived at the present invention as a result of intensive research into the influence of additives other than the color developer that constitute the color developer paper. In general, developer paper for pressure-sensitive copying paper requires an adhesive to firmly hold the developer to the base paper when the developer is contained inside or on the surface of the base paper. At the same time, the viscosity of the coating solution does not increase when the adhesive is dispersed in water together with developer particles and applied using a size press device or a coating device. It is necessary that the properties of the color developing paper obtained are not significantly impaired due to decrease in coating solution stability and coating suitability. Conventional adhesives used for color developer paper include starch, tin, gum arabic, styrene, butadiene copolymer latex, and vinyl acetate latex. It is said that it is desirable to use the necessary and minimum amount of these adhesives.

As a result of examining various adhesives conventionally used, the inventors of the present invention found that the properties of color developing paper vary significantly depending on the type of adhesive used. It has been discovered that by using at least one type of polyvinyl alcohol derivative with a degree of polymerization of 1000 or less, it is possible to provide a color developer paper with good resistance to yellowing caused by ultraviolet rays, color development, fading of a colored image, and ester resistance. . The effect of polyvinyl alcohol as an adhesive has been known for some time, but its effect on color developing paper is not clear.

The present inventors found that if a saponification degree of 95% or less is used, the color development of the color developing paper is significantly inferior, and if a polymerization degree of 100α or more is used, the liquid property of the coating liquid deteriorates and color development is significantly inhibited. This discovery led to the present invention. When using polyvinyl alcohol derivatives for actual color developer paper, when applying a water-based paint to the base paper by mixing it with a color developer and inorganic pigments such as calcium carbonate, zinc oxide, and kaolin, the liquid properties and optimal adhesion effects are determined. It is preferable to use it in combination with various types of latex in the same manner as with ordinary adhesives in view of the balance between Although it is difficult to set a specific limit because it largely depends on the coating method, it is preferable that the amount is at least within the required minimum amount of adhesive. Further, when using the polyvinyl alcohol derivative according to the present invention, the minimum amount to be effective is 0.5% or more based on the color developer. For example, for a coating liquid containing an acidic viscosity as a color developer and/or an inorganic pigment, the amount is 0.5 parts by weight to 100 parts by weight per 10 parts by weight of the acidic viscosity and/or inorganic pigment. If the amount added is less than 0.5 part, the effects of the present invention cannot be sufficiently achieved. Other adhesives used in conjunction with the above-mentioned polyvinyl alcohol derivatives, especially latexes, are not particularly limited, but commonly used styrene-butadiene copolymer latex, polyvinyl acetate latex, and methyl methacrylate-butadiene. It is possible to use polymer latex or the like.

) Derivatives of the polyvinyl alcohol mentioned above are not particularly limited as long as they are water-soluble when used, but examples include carboxy-modified polyvinyl alcohol, polyvinyl alcohol-styrene maleic anhydride copolymer, and polyvinyl alcohol-polyvinyl edether maleic anhydride copolymer. It is.

Although the present invention is described with respect to all color developer papers for pressure-sensitive copying paper, it can also be applied to conventionally well-known color-sensitive recording papers, which are common in that they utilize a color-forming reaction between an organic color former and an acidic color developer.

9 The effects of the present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

The various measured values in the Examples were obtained by the following method. In addition, all amounts are shown in parts by weight. ○ Coating fluid viscosity: Viscosity Cps at room temperature at 60 revolutions per minute using a B-type viscometer (model BLl Tokyo Keiki Seisakusho) ○ Blue color image, blue or black color developer coated on developer paper
Layer paper and press under pressure of 10kg/Cri.
MULTIPLIERPHOlOMET the color density after 1 minute through the per-calender
Values measured using ER (Tokyo Kohden KK) with a green filter for blue and no filter for black.

○Esterni-resistant Super Calendar produces blue color
The colored developing paper was sealed between vinyl chloride sheets, held between two glass plates, and heated at 60°C for 16 days.
After heating for several hours, the color density was measured.

O Blue coloring image: Blue coloring due to super calendar
The colored developer paper was left in a bright room for one week and the color density was then measured.

○Color-developing paper Fueni Stand Fuemeter (Model:
The color developer paper was treated with 6CfC for 3 hours using Model FA-1 (Toyo Rika Kogyo), and then the whiteness value (%) was measured using a solder whiteness tester (manufactured by Cardner Laboratories).

Example 1 7 parts of calcium carbonate, 3 parts of acid clay, and 10 m of P-phenylphenol (dispersion in water) were dispersed in water with 0.5 parts of sodium hexametaphosphate to give a solid content of 68%.
A slurry was prepared.

Each of these A] Degree of polymerization: 3001 Degree of saponification: 98%
8:2 copolymer of polyvinyl alcohol and polyvinyl methyl ether maleic anhydride, degree of polymerization 2200
Polyvinyl alcohol with a saponification degree of 1%, q] degree of polymerization 5
5 parts each of polyvinyl alcohol with a degree of saponification of 88% and w parts of styrene-butadiene copolymer latex were added and thoroughly stirred to obtain a coating liquid with a solid content of 53%. This coating solution was applied to 41 gI base paper using a coating rod so that the dry solid content was 6 gId on one side, and dried at 100°C. Table 1 shows the viscosity of the coating solution and the properties of the color developing paper.
Described in. As is clear from the results in Table 1, it is clear that the color developing paper (No. 1) prepared with the coating liquid composition of the present invention is excellent.

Sho NO. No. 2, which uses polyvinyl alcohol with a high degree of polymerization, and NO. Products with a low degree of saponification, such as No. 3, have high coating liquid viscosity and poor color development, making them undesirable. Not good.
Example 2 Nod of P-phenylphenol dispersed in water,
Kaolin clay (9) parts and acid clay 10 parts were thoroughly stirred and dispersed with 0.5 parts of sodium hexametaphosphate to obtain a slurry with a solid content concentration of 40%.

Each of these has a degree of polymerization of 6001 and a degree of saponification of 98%.
After adding a portion of carboxy-modified polyvinyl alcohol, phosphate esterified starch, and styrene-butadiene copolymer latex and stirring thoroughly, a size press solution with a solid content concentration of 20% was obtained.

Claims (1)

[Claims] 1 At least one of carboxy-modified polyvinyl alcohol, polyvinyl alcohol-styrene maleic anhydride copolymer, polyvinyl alcohol-polyvinyl ether maleic anhydride copolymer having a saponification degree of 95% or more and a polymerization degree of 1000 or less in the color developer layer. 2. The color developer paper for pressure-sensitive copying paper according to claim 1, wherein a part of the color developer is acidic clay.