JPS6129394B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ink composition for carbon paper. More specifically, in a carbon paper ink composition consisting essentially of base oil, wax, carbon black, and other necessary dyes and fillers, at least a portion of the wax itself has excellent hardness and gloss. , good hue,
It has no odor, and in relation to other ingredients, it has excellent hardness and gloss when mixed with base oil, has high oil retention, and has excellent carbon black dispersibility, dye dispersibility, and color development. This invention relates to a new type of superior carbon paper ink composition made by using a superior new wax. In general, carbon paper ink consists of base oil, wax, carbon black, and optionally dyes such as indigo and methyl violet, fillers such as fine clay powder, and resins. It aids in the mutual dispersion and bonding of the components, provides the ability to coat the ink onto the base paper, prevents the base oil from seeping onto the back of the base paper and other papers that are layered for copying, helps the color development of dyes, and provides the ability to coat the ink onto the base paper. To give gloss and smoothness to the ink surface, reduce the total amount of ink.
It is the most important component, accounting for 20 to 60% by weight, and it is no exaggeration to say that selecting a good wax or combination of waxes is the key to making a good carbon paper ink composition. The waxes currently used for this purpose are mainly natural waxes such as carnauba and montan, and their processed and modified products, but the prices of these natural products have soared in recent years, and the quality and supply system are unstable. Due to the large number of factors involved, efforts have been made to synthesize a wax suitable for this purpose for a long time, and although it has been used to some extent, a synthetic wax that is comparable in all aspects to the above-mentioned natural waxes has not been completed. It is known that waxes used for the above purposes need to contain oxygen in the form of ester groups, acid groups, etc. in order to satisfy the above-mentioned required properties, and synthetic waxes are generally made by oxidizing the wax base. However, this method has so far not been able to produce waxes with sufficiently high performance, and also gives off the characteristic odor of oxidation products and reduces thermal stability due to oxidative deterioration. The inevitable defects associated with oxidation, such as deterioration, cannot be avoided. In addition, as a special method for introducing oxygen into wax, a method is known in which an unsaturated polycarboxylic acid represented by maleic anhydride, or its anhydride or half ester is reacted. It is also known that wax suitable for various purposes can be made (for example, Japanese Patent Publication No. 46-10419, Japanese Patent Publication No. 47685-1973). Furthermore, in a similar attempt, it is known that a suitable wax-like substance can be obtained by copolymerizing a wax-like olefin compound and maleic anhydride using an organic peroxide or the like as an initiator. . (For example, Japanese Patent Publication No. 49-19708) As a result of studying the properties of the copolymerized wax of olefin and maleic anhydride (hereinafter simply referred to as copolymerized wax) obtained in this way, the present inventor found that
Although it exhibits excellent properties as a wax for carbon paper, it is recognized that it has many deficiencies compared to currently used natural waxes, etc., and has established a modification method that can correct and improve many of these defects. We completed a wax that showed far superior properties as a carbon paper wax than the polymerized wax itself and was comparable to the currently used natural wax, and used the wax thus obtained to prepare an ink for carbon paper.
The present invention was completed by confirming its excellent properties. That is, the carbon ink composition of the present invention is an ink composition for carbon paper consisting essentially of base oil, wax, carbon black, and other necessary components such as dyes and fillers, in which the wax component has a carbon number A waxy copolymer obtained by reacting more than 20 monoolefins with maleic anhydride under free radical-generating conditions, by replacing at least 1/6 or more of the acidic groups with divalent metal salts. The present invention is characterized in that it contains 5% by weight or more and 50% by weight or less of a metal-modified copolymerized wax based on the wax component. Below, the background of the establishment of the present invention will be described in detail. It is known that a wax-like copolymer is produced when a monoolefin having more than 20 carbon atoms is reacted with maleic anhydride under free radical-generating conditions. It is easily inferred that this is suitable as a raw material for ink for carbon paper, and it is known that many studies have been carried out. The necessary properties of wax as an ink composition for carbon paper include the hardness and gloss of the wax itself, an appropriate melting point, and viscosity, as well as the hardness of the mixture with the base oil,
It has excellent gloss, high oil retention, and excellent dispersibility of pigments such as carbon black. However, the above-mentioned copolymerized wax has these required properties within a sufficiently good range, and also shows extremely excellent dispersion performance for pigments such as carbon black. When mixed with wax, it does not have sufficient hardness or gloss, and its oil retention ability is also low, so it cannot be used on the same level as current natural waxes. As a result of searching for a method to correct and improve these defects that copolymer wax exhibits in relation to base oil, the present invention found that some or all of the acidic groups in copolymer wax are replaced with divalent groups such as Ca, Mg, and Zn. We found that various properties were significantly improved when converted to metal salts. In other words, as a copolymer wax, it is quite hard (ASTM-D-1321, penetration 4), has a glossy light yellow color (ASTMD-1544 Gardner value 3), has a saponification value (ASTMD-1387) of 96, and a melting point (ASTMD-1387) of 96. -127) 75℃, viscosity (Canon Fuenske method) of 170cp/100℃, and molecular weight (osmometry, benzene 36℃) of approximately 10,000. oil) as Nisseki High Motor MS30 (SAE
-30) in a 1:1 weight ratio and allowed to cool to room temperature, the mixture had a penetration of 80 and no particular gloss on the surface. Further bring this mixture to room temperature for 24 hours.
When left for a long time, a sweating phenomenon was observed on the surface.
When kept at ℃, a large amount of oil oozes out onto the surface of the paper, indicating that the so-called oil retention ability is extremely poor. However, this copolymerized wax is modified with Ca in the method described later, and 1/4 of the acidic groups (corresponding to a saponification value of 96) in the copolymerized wax are converted to Ca salts. When mixed with equal amounts of base oil in the same manner as above, the penetration of the mixture is 49, which is significantly harder than the unmodified copolymer wax's 80, and the surface has a beautiful mirror-like luster, making it easy to apply on cardboard. When the 60° reflectance was measured, it showed a high value of 88%. This is an unmodified copolymer wax.
This is a significant improvement compared to 42%, and is comparable to the measured value of 91% for Hoechst OP wax (manufactured by Hoechst), which is highly rated as a currently used wax for carbon ink. Furthermore, a mixture of equal amounts of this Ca-modified wax and base oil was poured into a cylindrical shape with a diameter of 20 mmφ and a thickness of 10 mm (bottom area
3.14cm ² ), place on thin paper and heat at 50℃.
When the wax was allowed to stand for three days and nights, the area of the oil stain that oozed out on the surface of the first sheet of paper was 32.3 cm ² , indicating that the oil retention property was improved compared to 47.2 cm ² of the copolymerized wax before modification. ing. On the other hand, this type of copolymerized wax is characterized by extremely high pigment dispersibility. For example, put 94.5 parts by weight of 125% paraffin, 5 parts by weight of various waxes, and 0.5 parts by weight of carbon black into a test tube, and melt it. After mixing and standing at 120°C to observe the dispersion state of carbon black, it was found that waxes currently used in carbon paper inks such as carnauba and Hoechstwax or widely used as dispersion improvers of this type. Even with stearic acid, oleic acid, etc., most of the carbon black settles out after several hours or a day, and the upper layer becomes transparent. In addition, in a few commercially available waxes that are known to have good dispersibility, some of the carbon black remains and disperses in the upper layer, causing the upper layer to be colored pale black. In the case of wax, even after three days, the upper layer remains completely black because a large amount of carbon black particles remain and are dispersed in the upper layer. It was confirmed that the excellent pigment dispersibility exhibited by this copolymerized wax did not change significantly even after Ca modification, and the same performance was maintained. Furthermore, 1/2, 3/4 of the acidic groups of copolymerized wax
When we converted the equivalent amount to Ca and examined the changes in properties due to changes in Ca content, we found that there was no significant difference from the case of 1/4 amount, but the hardness of an equal weight mixture with base oil,
and oil retention improved with increasing Ca content. Therefore, it was found that although a Ca content corresponding to a portion of the acidic group sufficiently exhibits a modifying effect, the effect can be further enhanced by increasing the Ca content. Furthermore, when Mg and Zn were used in place of Ca, the properties of an equal weight mixture of wax and base oil and the dispersibility of carbon black were found to be the same as those of Ca. However, when Zn is used, the wax itself becomes slightly reddish-brown.
is said to be the best material. A wax-like substance (copolymerized wax) obtained by copolymerizing a monoolefin having more than 20 carbon atoms and maleic anhydride under free radical-generating conditions.
A part (1/6 or more, preferably 1/4 or more) of the acidic groups of
Metal-modified copolymer waxes obtained by modifying , or all of them with divalent metal salts such as Ca, Mg, and Zn have improved hardness, gloss, and oil retention when mixed with base oil compared to before modification. On the other hand, the dispersibility of pigments such as carbon black, which is a characteristic of copolymer wax, is not affected by modification, so carbon paper whose main components are base oil, wax, and pigments such as carbon black. It is suitable as an ink composition for. However, even though it has been improved, the oil retention is not sufficient, so it is inappropriate to use this wax as a single wax component.
It is suitable to use it in combination with other waxes as an agent for improving gloss and other physical properties of carbon paper ink. The wax in the ink composition of the present invention is used as a mixed wax together with the wax converted into the divalent metal salt and other waxes such as carnauba wax and montan wax. It is appropriate to blend the wax converted into the divalent metal salt in an amount of 5% to 50% by weight in the mixed wax; however, if it is blended in an amount of 5% or more, the ink composition for carbon paper will have a favorable effect. , for example, can improve gloss and reflectance, and if it is less than 5% by weight, it is difficult to obtain the above effects,
In addition, if the amount exceeds 50% by weight, the oil retention properties of the wax mixture will decrease. Next, the formulation of the ink composition for carbon paper according to the present invention can be expressed very generally as follows: Base oil: 10 to 50 parts by weight Waxes: 20 to 60 parts Carbon black: 5 to 25 parts by weight; As a base, small amounts (1 to 5 parts by weight) of fillers such as clay powder, petroleum resins, and plastics may be added to this as dyes to improve color tone, and hardness improvers. Inexpensive fillers may be incorporated in relatively large amounts (10 to 30 parts by weight) as extenders mainly for economic reasons. Also, waxes are often mixtures of two, three or more waxes, either to impart desirable properties or for economic reasons. Some or all of the acidic groups in the copolymerized wax
There are various methods of converting Ca into Ca, and waxes made using any of them will result in equally good carbon paper ink compositions. For example, in copolymer wax melted at 150℃,
When a 30 wt% CaC ₂ aqueous solution is added dropwise over 0.5 to 2 hours, the reaction proceeds smoothly and quantitatively while water and HC are volatilized. The same is true for calcium acetate aqueous solutions, but since calcium acetate has low solubility in water at room temperature, the concentration must be kept below 20wt%, which increases the amount of water that must be volatilized, which is disadvantageous from a thermoeconomic perspective. Become. After the reaction is completed, the temperature is maintained at normal pressure with or without _N2 injection, or at 100-3 mm.
A Ca-modified copolymer wax can be obtained by removing volatile substances by evaporation under a reduced pressure of about Hg for 0.5 to 2 hours. Even if powders such as CaO and Ca(OH) ₂ are added to copolymerized wax and stirred, no reaction occurs until 300℃.
When a small amount of LiC is added to this system, the reaction progresses, but it is not quantitatively completed and a white powder always remains in the system after completion, which requires a step to remove it. When a small amount of water or an aqueous solution of a volatile acid such as HC is added to a system in which powders such as CaO and Ca(OH) ₂ are added to a copolymerized wax, the reaction proceeds satisfactorily even at temperatures around 150°C. However, strong foaming occurs during the reaction in this system, so sufficient measures must be taken to prevent this. Similarly, the reaction proceeds in a system in which an aqueous HC solution is added to CaCO ₃ powder. The wax produced by converting some or all of the acidic groups of the copolymerized wax into Ca salt has excellent hardness and gloss, good hue, no odor, and has a lower melting point than hardness. In addition, in relation to other ingredients, it has excellent gloss when mixed with base oil, good hue, hardness and oil retention compared to unmodified copolymerized wax, and has excellent dispersion of carbon black, dyes, etc. This wax is suitable as an ink composition for carbon paper due to its excellent color properties and color development.However, these properties are not limited to carbon paper, and this wax is suitable for shoe cream, plastic additives, and many other uses. It is shown that. In order to specifically explain the present invention, comparative examples and examples are shown below, but it goes without saying that the content of the present invention is not limited to the examples. Example 1 C ₂₈ to C ₅₀ (average carbon number
33) 200g of the copolymer (copolymer wax) of olefin and maleic anhydride was heated to 150℃ and stirred.
13 c.c. of a 30 wt% aqueous solution of CaC ₂ was added dropwise over 0.5 hour, and stirring was continued for an additional 0.5 hour. then 0.5 hours
Volatile components were removed by bubbling N ₂ and then distilling under a 5 mmHg vacuum for 1 hour. These reaction conditions correspond to a calculated amount in which 25% of the acidic groups contained in the wax are converted to Ca salts. After the reaction was completed, the infrared absorption spectrum showed that saponification had occurred as calculated. The properties of the product are shown in Table 1. Example 2 50 g of the same copolymerized wax as in Example 1 was heated to 150°C and stirred, and 2.2 g of Ca(OH) ₂ powder was added to give a 1N
An acetic acid aqueous solution was added dropwise intermittently over 1 hour. The reaction proceeded with quite intense bubbling. After the completion of the dropwise addition, N ₂ was blown in for 0.5 hours, followed by distillation under a reduced pressure of 5 mmHg. These reaction conditions corresponded to the calculated amount to convert 3/4 of the acidic groups contained in the wax into Ca salts, and the infrared absorption spectrum showed that the calculated amount of reaction had occurred. The properties of the product are shown in Table 1. Example 3 20g of the same copolymer wax as in Example 1 and ZnC
₂ A reaction exactly the same as in Example 1 was carried out using 3.0 cc of a 30 wt% aqueous solution. These reaction conditions correspond to the amount calculated to convert 50% of the acidic groups contained in the wax into Zn salts. The product was a very hard wax with a metallic luster, but it was colored and had a reddish-brown color.
The properties of the product are shown in Table 1. Comparative Example 1 To 20 g of the product prepared in the same manner as in Example 1,
1.3g of Ca(OH) ₂ powder was added and stirred at 275°C for 8 hours. These reaction conditions correspond to the calculated amount that the total amount of acidic groups contained in the wax will be converted to Ca salts if the reaction is completed. However, when stirring was stopped, a white powder settled at the bottom of the system, and the infrared absorption spectrum showed that the saponification reaction had hardly progressed. Example 4 In the same reaction as in Comparative Example 1, the temperature was lowered to 200°C,
When 2 c.c. of water was added dropwise intermittently, the reaction proceeded with intense bubbling, and the dropwise addition was completed in 1 hour, but the infrared absorption spectrum of the product showed almost complete completion of the saponification reaction. . The properties of the product are shown in Table 1. Example 5 The basic properties of various waxes (conventionally known waxes and waxes obtained in Examples 1 to 4) and mixtures of these waxes and base oils were measured, and Tables 1, 2, and 2 A comparative description is given in -3. A sample was prepared by mixing SAE30 lubricating oil (Nisseki High Motor MG30) as a base oil with the wax at a weight ratio of 1:1 and thoroughly stirring at 120°C. As shown in Table 1, the hardness of the mixture is not necessarily related to the hardness of the wax itself and shows a specific value, but all of the waxes in the examples were significantly harder than the copolymerized waxes before modification. ing. Although gloss can be measured simply by observation,
Furthermore, it was coated on standard gloss test paper (Japan Test Panel Industries Co., Ltd. Hidden Rate Test Paper) and the 60° reflectance was measured. (Toyo Rika Kogyo Co., Ltd. OH-1 type) Table of results -
Shown in 2. For waxes and mixtures, the solid surface observation results are given in four grades: very good (◎), good (○), not very good (△), and poor (×), but the evaluation changes when it is made into a coating film. There are cases. Among the control products, Hoechst OP is very good, but Carnaupawatkus does not show luster. Each of the waxes in the Examples is almost comparable to Hoechst OP and exhibits a gloss that is very similar to Hoechst OP. Furthermore, when 10% of the wax of Example 1 is added to carnauba wax, the gloss is improved and the reflectance is increased to 33% of that without additives. Oil retention refers to the ability to prevent base oil from seeping onto the paper surface, and is an essentially important property for carbon paper waxes. A mixture of wax and oil with a diameter of 20mmφ and a thickness of 10mm.
It was molded into a cylindrical shape (bottom side 3.14 cm ² ), and left standing at 50°C for three days and nights on top of 10 sheets of thin paper sheets (Giacom). The area of the oil stain on the first sheet indicates oil retention (the smaller the number, the better the oil retention). Carnauba wax is an outstanding wax in this respect, and although the waxes of Examples do not exhibit sufficient performance in this respect, they are markedly improved compared to the copolymer wax before modification. Example 6 A trial carbon paper was produced using the wax of the present invention. Prescription Base oil (Nisseki High Motor MS30) 200g Wax (from Example 1) 12g Carnauba No. 2 36g Paraffin (Nisseki Paraffin 135) 80g Carbon Black (Mitsubishi Kasei MA100)
68g Methyl Violet 4g Total 400g Mix the entire composition for 1 hour in a ball mill kept at 120°C to make ink, and apply this to the back of thin paper (Giacom) with a roller to make it equivalent to spot carbon paper. . The ink was evenly applied, had a good gloss, and did not smear when layered with paper. Repeated copying was possible up to four times, which was superior to commercially available carbon paper on the back of slips. Comparative Example 2 An ink was prepared in the same manner as in Example 6, except that the entire amount of wax was replaced with Carnauba No. 2. The resulting carbon paper showed almost the same performance as Example 6, but
No surface gloss was observed. Example 7 The following experiment was conducted to compare the dispersibility of carbon black. 125〓paraffin in a test tube
Add 94.5 parts by weight, 5 parts by weight of various waxes, and 0.5 parts by weight of carbon black (Mitsubishi Kasei MA100).
After melt-mixing and standing at 120°C for three days and nights, the state of carbon black dispersion in the paraffin layer was observed. The results are shown in Table-3. The dispersion state was evaluated in three irregular stages as follows. 1... Most of the material has settled, and the paraffin layer is almost transparent. 3...The paraffin layer, which remained and dispersed in large quantities, is dark black. 2...Intermediate between 1 and 3, depending on the degree of blackness of the paraffin layer, from light to dark 2.2, 2.4,
...Evaluated in increments of 2.8 and 0.2, however, because it is a visual observation, the numerical value does not have much quantitative meaning. As mentioned above, carbon ink compositions containing a metal-modified copolymer wax as a wax component together with base oil and carbon black have superior gloss, hardness, oil retention, and pigment content compared to conventional carbon ink compositions. Provides excellent dispersibility.

【table】

【table】

【table】

【table】

【table】

Claims (1)

[Scope of Claims] 1. In a carbon paper ink composition consisting essentially of base oil, wax, carbon black, and other necessary components such as dyes and fillers, the wax accounts for 5 to 50% by weight of the amount thereof. Within this range, at least 1/6 or more of the acidic groups of the wax-like copolymer obtained by reacting a monoolefin having more than 20 carbon atoms with maleic anhydride under free radical-generating conditions are divalent metal salts. An ink composition for carbon paper, comprising a metal-modified copolymer wax obtained by converting the wax into a metal-modified copolymer wax. 2. The ink composition for carbon paper according to claim 1, wherein the divalent metal is Ca, Mg or Zn. 3. Claim 1, which comprises 20 to 60 parts by weight of a wax containing 5 to 50 parts by weight of the metal-modified copolymer wax, 10 to 50 parts by weight of base oil, and 5 to 25 parts by weight of carbon black. The ink composition for carbon paper according to item 1 or 2.