DEINKING AGENT

Abstract: A deinking composition comprises a reaction product obtained by reacting a glyceride mixture derived from natural oil and fat with ethylene oxide and propylene oxide, (a) said glyceride mixture (a) comprising 5 to 10 percent by weight of monoglycerides, 30 to 45 percent by weight of diglycerides and 50 to 70 percent by weight of triglycerides, (b) said reaction product having a molar ratio of ethylene oxide to propylene oxide in the range between 1.8 and 2.2, (c) said reaction product having the mole number of added ethylene oxide in the range between 30 and 80 on the average based on a mole of glycerides.

Description: The present invention relates to a deinking agent which is used for the reclamation of waste paper such as newspapers and magazines. More particularly, the present invention relates to a deinking agent which yields deinked pulp having a higher b value and containing a less amount of sticky substance when used for the deinking treatment by floatation method, washing method, or a compromise method thereof. Prior art The reclamation of waste paper such as newspapers and magazines is an old practice. An importance is being attached to the effective reclamation of waste paper because of the recent supply shortage and price hike of pulp sources. In addition, deinked pulp is finding more valuable uses than before. On the other hand, the reclamation of waste paper is becoming difficult from the standpoint of deinking on account of the recent change in printing technology, printing method, and printing ink, and the utilization of waste paper which has never been reclaimed in the past. For more effective deinking, improvements are being made on the existing machine. A variety of chemicals have been used to separate and remove ink and other impurities from waste paper. They include alkali agents (such as sodium hydroxide, sodium silicate, sodium carbonate, and sodium phosphate), bleaching agents (such as hydrogen peroxide, hyposulfite, hypochlorite), and sequestering agents (such as EDTA and DTPA), and deinking agent. Examples of the deinking agent include anionic surface active agents (such as alkylbenzenesulfonate, higher alcohol sulfate ester salt, α-olefinsulfonate, and dialkylsulfosuccinate) and nonionic surface active agents such as an adduct of a higher alcohol, an alkylphenol or a fatty acid and an alkanolamide. They may be used either by itself or in combination with one another. Unfortunately, the conventional deinking agent is poor in ink catching performance although it is good in foaming performance when used in the floatation process. Also, when it is used in the washing process, it is poor in detergency and generates a large amount of foam which causes trouble during draining. Thus, with the conventional deinking agent, it was only possible to obtain deinked pulp of low grade. Moreover, deinked pulp obtained by using the conventional deinking agent is limited in its application area because it looks dark and dull. (It can be used only in a reduced amount in paper board and newsprint paper.) To eliminate the dull appearance, it is necessary to use more bleaching agent than necessary. One way of producing deinked pulp having a bright color tone is to increase the b value. It is possible to increase the b value if an alkaline agent is used in large quantities. However, this increases sticky substances and water discharge load and makes the resulting pulp brittle. There has been no effective means to eliminate these disadvantages. The present inventors proposed using as a deinking agent a reaction product obtained by adding an alkylene oxide to a mixture composed of a natural fat or oil and a tri- or polyhydric alcohol. (See Japanese Patent Laid-open No. 239585/1985.) After careful examination on its behavior in the deinking process, it was found that it causes foaming troubles in the floatation step, dehydration step, draining step, and papermaking step, if it is composed of a natural fat or oil and a tri- or polyhydric alcohol in a molar ratio of 1:0.5 to 1:3. Moreover, it has a disadvantage that it does not eliminate the dull appearance completely although it provides deinked pulp having a high degree of whiteness. Summary of the Invention The present inventors carried out a series of researches on the development of a deinking agent which will exhibit the outstanding ink removing performance without foaming trouble in the floatation method or washing method or a compromise method thereof, and provide deinked pulp having a high b value (without dull appearance) and containing a less amount of sticky substances. It was unexpectedly found that the above-mentioned requirements can be met when the deinking agent contains a specific nonionic surface active agent. This finding led to the present invention. Accordingly, it is an object of the present invention to provide a deinking agent which comprises a natural fat or oil and an ethylene oxide/propylene oxide adduct of glyceride mixture composed of 5-10 wt% of monoglyceride, 30-45 wt% of diglyceride, and 50-65 wt% of triglyceride, said adduct containing ethylene oxide and propylene oxide in a molar ratio of 1.8-2.2 and also containing ethylene oxide in an amount of 30-80 mol. A deinking composition comprises a reaction product obtained by reacting a glyceride mixture derived from natural oil and fat with ethylene oxide and propylene oxide, (a) said glyceride mixture (a) comprising 5 to 10 percent by weight of monoglycerides, 30 to 45 percent by weight of diglycerides and 50 to 65 percent by weight of triglycerides, (b) said reaction product having a molar ratio of ethylene oxide to propylene oxide in the range between 1.8 and 2.2, (c) said reaction product having the mole number of added ethylene oxide in the range between 30 and 80 on the average based on a mole of glycerides. The reaction is normally conducted with natural oil and fat, glycerine, propylene oxide and ethylene oxide in the presence of an alkali catalyst. It is relatively free from sticky matters. It is preferred that the reaction is conducted with a mixture of ethylene oxide and propylene oxide and the product is a reaction product obtained by random addition reaction of both oxides. The invention provides a method for reclamation of waste paper with the use of a deinking agent comprising the above defined reaction product and then the use of the reaction product for a deinking agent. The fat and oil that can be used in the present invention include vegetable oils (such as coconut oil, palm oil, olive oil, soybean oil, rapeseed oil, linseed oil, castor oil, and sunflower oil), land animal fat and oil (such as lard, beef tallow, and bone oil), aquatic animal fat and oil (such as sardine oil and herring oil), hardened oil and semihardened oil thereof, and recovered oil obtained in the purification step for these fats and oils. According to the present invention, the glyceride mixture should be composed of 5-10 wt% of monoglyceride, 30-45 wt% of diglyceride, and 50-65 wt% of triglyceride. The glyceride mixture meeting this requirement effectively removes fine ink particles and yields deinked pulp having a bright color tone free of dull appearance and hence having a high b value. If this requirement is not met, it will not eliminate the dull appearance completely from deinked pulp. This requirement may be met by mixing ready-made monoglyceride, diglyceride, and triglyceride in a desired ratio, or by adding glycerin to a natural fat or oil (triglyceride) for the ester interchange reaction that brings about the desired ratio. According to the present invention, the addition of ethylene oxide and propylene oxide may be accomplished simultaneously (random addition) or sequentially (block addition), with the former being preferable from the standpoint of decreasing the foaming troubles. According to the present invention, the addition of ethylene oxide and propylene oxide should be carried out in a molar ratio of 1.8 to 2.2, and the amount of ethylene oxide added should be 30 to 80 mol. If this requirement is not met, the resulting deinking agent is poor in the ability to remove ink from waste paper and also poor in foaming performance in the case of floatation treatment or in ink removing performance in the case of washing treatment. The only compound which meets this requirement is effective in reducing sticky substances. In other words, deinked pulp having a high b value and containing a less amount of sticky substances can be obtained only by using the compound which meets the above-mentioned requirements. In the present invention, the method of adding ethylene oxide and propylene oxide is not specifically limited. The addition reaction may be carried out under the conditions which are usually employed when alkylene oxides are added to a compound containing an active hydrogen. Thus, the addition reaction involves the steps of charging glycerides in the above-mentioned ratio (by weight), adding a catalytic amount of alkaline substance to the glyceride mixture, and reacting the glyceride mixture with ethylene oxide and propylene oxide at about 100-200°C for several hours under a pressure of 1-3 kg/cm²G. The deinking agent of the present invention may be used to advantage in combination with any known deinking agent such as high alcohol sulfate, alkylbenzenesulfonate, higher alcohol, and ethylene oxide adduct of alkylphenol. The deinking agent of the present invention may be added in portions to any or all of the waster paper breaking step, high-consistency bleaching step, and floatation preliminary step. It should be added in an amount of 0.03 to 1.0 wt% of the amount of waste paper. Examples The invention will be described in more detail with reference to the following manufacturing examples and working examples, which are not intended to restrict the scope of the invention. Manufacturing Example 1 In a 1.5-liter autoclave were placed 16.2 g of monoglyceride of coconut oil, 52.0 g of diglyceride of coconut oil, 97.2 g of triglyceride of coconut oil, and 1.9 g of 100% KOH. The contents were heated to 150°C with stirring at about 600 rpm. To the glycerides was slowly added 479.9 g of ethylene oxide at 150-160°C under a pressure of 1-3 kg/cm²G. After the completion of the addition reaction of ethylene oxide, the reaction system was cooled to 120-130°C, and 350.9 g of propylene oxide was added under a pressure of 1-3 kg/cm²G. The reaction product was cooled to 80°C and neutralized to pH 6 with acetic acid. The yield of the reaction product (No. 1 in Table 1) was 97%. Manufacturing Example 2 In a 1.5-liter autoclave were placed 9.3 g of monoglyceride of beef tallow, 69.1 g of diglyceride of beef tallow, 103.3 g of triglyceride of beef tallow, and 1.9 g of 100% KOH. The contents were heated to 130°C with stirring at about 600 rpm. To the glycerides was added 814.5 g of a mixture composed of ethylene oxide and propylene oxide in a molar ratio of 2:1. The addition reaction was carried out at 130-140°C under a pressure of 1-3 kg/cm²G. After the completion of the addition reaction, the reaction system was cooled to 80°C and neutralized to pH 6 with acetic acid. The yield of the reaction product (No. 17 in Table 2) was 98%. Example 1 Various deinking agents as shown in Table 1 were evaluated in the following manner. Waste paper composed of 50 wt% of news and 50 wt% of magazine was cut into small pieces (2 × 5 cm), and a certain amount of cut waste paper was placed in a desk-top breaker. To the breaker were added water, 1.0% of sodium hydroxide, 2.5% of sodium silicate No. 3, 3.0% of 30% hydrogen peroxide, and 0.2% of the deinking agent shown in Table 1. (The percentage is based on the amount of waste paper.) Breaking was carried out in a 5% pulp concentration at 45°C for 20 minutes, followed by aging at 45°C for 60 minutes. After dilution with water to a pulp concentration of 1.0%, floatation was carried out at 30°C for 10 minutes until the pulp slurry was concentrated to 6%. The pulp slurry was diluted with water to 1% and then made into a pulp sheet by means of a TAPPI standard sheet machine. The thus obtained pulp sheet was tested for b value by the aid of a color difference meter and also for the number of sticky objects by the aid of an image analyzer (×40). The amount of foamy liquid (required to form the foam layer) which was generated during floatation was measured as a measure of foaming performance. (The more the foamy liquid, the lower the yield and the poorer the froth handling in the water treatment.) The b value means the b value in the Lab color space of Hunter color difference. It has a relationship with the tristimulus values as represented by the following formula. b = 7.0(Y - 0.847Z)/√Y It is noted that the b value is a function of Y and Z, and positive b values indicate a yellowish tone and negative b values indicates a bluish tone. Table 1 shows the ratio of the glycerides in each deinking agent and the performance of each deinking agent. Example 2 Various deinking agents as shown in Table 2 were evaluated in the following manner. Waste paper of magazine was cut into small pieces (2 × 5 cm), and a certain amount of cut waste paper was placed in a high-consistency pulper. To the pulper were added water, 0.5% of sodium hydroxide, 1.5% of sodium silicate No. 3, 1.0% of 30% hydrogen peroxide, and 0.05% of the deinking agent shown in Table 2. (The percentage is based on the amount of waste paper.) Breaking was carried out in a 15% pulp concentration at 45°C for 20 minutes. The pulp slurry was diluted with water to a pulp concentration of 4.0%, and further diluted with water to a pulp concentration of 1.0%. The pulp slurry was subjected to floatation at 30°C for 10 minutes until the pulp slurry was concentrated to 6%. The pulp slurry was diluted with water to 1% and then made into a pulp sheet by means of a TAPPI standard sheet machine. The thus obtained pulp sheet was tested for b value by the aid of a color difference meter and also for the number of sticky objects by the aid of an image analyzer (×40) . The amount of foamy liquid (required to form the foam layer) which was generated during floatation was measured as a measure of foaming performance. Table 2 shows the molar ratio of ethylene oxide and propylene oxide in each deinking agent and the performance of each deinking agent. Example 3 Various deinking agents as shown in Table 3 were evaluated in the following manner. Waste paper of magazine was cut into small pieces (2 × 5 cm), and a certain amount of cut waste paper was placed in a low-consistency pulper. To the pulper were added water, 0.5% of sodium hydroxide, 1.5% of sodium silicate No. 3, 1.0% of 30% hydrogen peroxide, and 0.06% of the deinking agent shown in Table 3. (The percentage is based on the amount of waste paper.) Breaking was carried out in a 4% pulp concentration at 40°C for 15 minutes. The pulp slurry was diluted with water to a pulp concentration of 1.0%. The pulp slurry was subjected to floatation at 30°C for 10 minutes until the pulp slurry was concentrated to 6%. The pulp slurry was diluted with water to 1% and then made into a pulp sheet by means of a TAPPI standard sheet machine. The thus obtained pulp sheet was tested for b value by the aid of a color difference meter and also for the number of sticky objects by the aid of an image analyzer (×40). The amount of foamy liquid (required to form the foam layer) which was generated during floatation was measured as a measure of foaming performance. Table 3 shows the amount (in mol) of ethylene oxide added to the glycerides in each deinking agent and the performance of each deinking agent. Example 4 Various deinking agents as shown in Table 4 were evaluated in the following manner. Waste paper composed of 50 wt% of news and 50 wt% of magazine was cut into small pieces (2 × 5 cm), and a certain amount of cut waste paper was placed in a desk-top breaker. To the breaker were added water, 0.8% of sodium hydroxide, 2.0% of sodium silicate No. 3, 2.0% of 30% hydrogen peroxide, and 0.5% of the deinking agent shown in Table 4. (The percentage is based on the amount of waste paper.) Breaking was carried out in a 5% pulp concentration at 50°C for 15 minutes, followed by aging at 50°C for 2 hours. After dilution with water to a pulp concentration of 1.0%, floatation was carried out at 30°C for 10 minutes until the pulp slurry was concentrated to 6%. The pulp slurry was diluted with water to 1% and then made into a pulp sheet by means of a TAPPI standard sheet machine. The thus obtained pulp sheet was tested for b value by the aid of a color difference meter and also for the number of sticky objects by the aid of an image analyzer (×40) . The amount of foamy liquid (required to form the foam layer) which was generated during floatation was measured as a measure of foaming performance. Table 4 shows the sequence of adding alkylene oxides to glycerides in each deinking agent and the performance of each deinking agent.

Claims: A deinking composition which comprises a reaction product obtained by reacting a glyceride mixture derived from natural oil and fat with ethylene oxide and propylene oxide, (a) said glyceride mixture comprising 5 to 10 percent by weight of monoglycerides, 30 to 45 percent by weight of diglycerides and 50 to 65 percent by weight of triglycerides, (b) said reaction product having a molar ratio of ethylene oxide to propylene oxide in the range between 1.8 and 2.2, (c) said reaction product having the mole number of added ethylene oxide in the range between 30 and 80 on the average based on a mole of glycerides. The composition as claimed in claim 1, in which the reaction is conducted with natural oil and fat, glycerine, propylene oxide and ethylene oxide in the presence of an alkali catalyst. The composition as claimed in Claim 1, in which the reaction is conducted with a mixture of ethylene oxide and propylene oxide and the product is a reaction product obtained by random addition reaction of both oxides.

Inventors: HAMAGUCHI, KOJI, HIRAMATSU, HIROYOSHI, MIYAUCHI, YOSHITAKA, URUSHIBATA, HIDEAKI
Applicants: KAO CORPORATION
Application year: 1989
Main classification: D21C5
IPC codes: D21C5