Antifouling composition

Abstract

To provide a pollution prevention agent composition sufficiently excellent in pollution prevention effect and its long-lasting property.SOLUTION: The invention relates to a pollution prevention agent composition used in applying to a dry part D of a papermaking process and comprises an emulsion composed of a silicone-based oil which is liquid at an ordinary temperature, an aqueous medium which is liquid at an ordinary temperature, and a dispersant for dispersing the silicone-based oil in the aqueous medium, wherein the aqueous medium is composed of water and a polyhydric alcohol dissolved in water, a boiling point of the polyhydric alcohol is higher than 100°C, a blending ratio of the silicone-based oil to 1 pt.mass of the polyhydric alcohol is 0.5-50 pts.mass, a blending ratio of water to 1 pt.mass of the polyhydric alcohol is 25-300 pts.mass, and a blending ratio of the dispersant to 1 pt.mass of the polyhydric alcohol is 0.1-50 pts.mass.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stain inhibitor composition that is applied to the dry part of the papermaking process. [Background technology]

[0002] The papermaking process generally includes a wire part in which a liquid in which pulp is dispersed in water is placed on a papermaking mesh (wire) and excess water is allowed to fall naturally to form a wet paper; a press part in which the wet paper is passed between a pair of press rolls and pressed by the press rolls through a felt, thereby transferring the water in the wet paper to the felt, thereby dehydrating the wet paper; a dry part in which the wet paper that has passed through the press part is brought into succession through a canvas into contact with multiple heated dryer rolls to dry it and form paper; a calender part in which the paper is passed between calender rolls to smooth out any surface irregularities; and a reel part in which the paper is wound onto a spool.

[0003] However, in the above-mentioned dry part, if contaminants such as pitch or paper dust adhere to the surface of the roll that guides the wet paper, the contaminants will transfer and adhere to the roll each time the paper is guided by the roll, resulting in a significant drop in yield.

[0004] In response to this, in order to prevent contamination in the dry part of a paper machine as much as possible, a stain-preventing composition that is applied to the dry part is known (see, for example, Patent Document 1). Such a stain-proofing composition comprises an emulsion containing an amino-modified silicone and a re-emulsifying agent. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-186141 Summary of the Invention [Problem to be solved by the invention]

[0006] However, although the antifouling composition described in Patent Document 1 exhibits some antifouling effect, the duration of the antifouling effect cannot be said to be excellent.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antifouling composition that has a sufficiently excellent antifouling effect and that effect lasts for a long time. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems and have come up with the idea of ​​incorporating a predetermined amount of polyhydric alcohol, which is difficult to evaporate even when applied to a heated roll, into the aqueous medium that constitutes the emulsion. The inventors have found that the above problems can be solved by adjusting the blending ratios of silicone oil, water, and dispersant to polyhydric alcohol within respective specified ranges, and have thus completed the present invention.

[0009] The present invention provides a stain-proofing composition that is applied to the dry part of a papermaking process, and is an emulsion having a silicone-based oil that is liquid at room temperature, an aqueous medium that is liquid at room temperature, and a dispersant for dispersing the silicone-based oil in the aqueous medium, wherein the aqueous medium is composed of water and a polyhydric alcohol dissolved in the water, the polyhydric alcohol having a boiling point higher than 100°C, the blending ratio of the silicone-based oil per 1 part by mass of the polyhydric alcohol is 0.5 to 50 parts by mass, the blending ratio of water per 1 part by mass of the polyhydric alcohol is 25 to 300 parts by mass, and the blending ratio of the dispersant per 1 part by mass of the polyhydric alcohol is 0.1 to 50 parts by mass.

[0010] In the stain preventive composition of the present invention, the polyhydric alcohol is preferably at least one selected from the group consisting of glycerin, ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol.

[0011] In the stainproofing composition of the present invention, the polyhydric alcohol is preferably polyethylene glycol which is liquid at room temperature, and the polyethylene glycol preferably has 3 to 15 repeating oxyethylene units. In this case, in the stain-proofing composition, the hydroxyl value of the polyethylene glycol is preferably 200 or more.

[0012] The stain inhibitor composition of the present invention is used to apply the composition to an upstream roll located on the upstream side of a plurality of rolls in a dry part to form a liquid coating, bring a running body into contact with the liquid coating to transfer a portion of the liquid coating to the running body, and then bring the running body into contact with a downstream roll located downstream of the upstream roll to transfer the liquid coating to the downstream roll, and the roll is preferably a dryer roll or a canvas roll, and when the roll is a dryer roll, the running body is a wet paper web, and when the roll is a canvas roll, the running body is a canvas. In this case, it is preferable that the upstream roll and downstream roll of the antifouling composition are made of cast iron, that the contact angle with the upstream roll and downstream roll is 70° or less, that the viscosity is 0.001 to 1.5 Pa s, and that the dynamic surface tension is 25 mN / m or more. [Effects of the Invention]

[0013] The stain inhibitor composition of the present invention is an emulsion of a silicone-based oil that is liquid at room temperature, an aqueous medium that is liquid at room temperature, and a dispersant. This aqueous medium contains a predetermined amount of a polyhydric alcohol with a boiling point higher than 100°C, which makes the aqueous medium less likely to evaporate compared to water alone due to a so-called vapor pressure drop. Therefore, when the stain inhibitor composition is applied to a heated roll, the aqueous medium is allowed to remain on the roll as much as possible, thereby maintaining the emulsion state as much as possible. Furthermore, the polyhydric alcohol itself is aqueous, which contributes to maintaining the emulsion state. In the above-mentioned anti-fouling composition, as described above, by maintaining the emulsion state as much as possible, it is possible to fully exert the anti-fouling effect based on the silicone-based oil and to fully maintain the anti-fouling effect (hereinafter also simply referred to as the "maintenance effect"). Incidentally, when the aqueous medium evaporates and the emulsion state collapses, even if the silicone oil acts on contaminants, it becomes difficult to peel or remove them with water because the silicone oil is oily.

[0014] In the antifouling composition of the present invention, by setting the blending ratio of silicone oil, blending ratio of water, and blending ratio of dispersant per part by mass of polyhydric alcohol within the above ranges, the antifouling effect and maintenance effect can be fully exhibited. It also improves the dispersibility of the silicone oil, which allows it to be uniformly dispersed in the aqueous medium, and the storage stability, which prevents the two from separating over time. This reduces uneven application and further improves the stain prevention effect.

[0015] In the antifouling composition of the present invention, when the polyhydric alcohol is at least one selected from the group consisting of glycerin, ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol, the antifouling composition is inexpensive due to its excellent versatility and has excellent compatibility with water, allowing the antifouling effect and maintenance effect to be more fully exerted.

[0016] Among these, when the polyhydric alcohol is polyethylene glycol that is liquid at room temperature and the number of repeating oxyethylene units in the polyethylene glycol is 3 to 15, the contribution of the polyhydric alcohol itself to maintaining the emulsion state is increased, and therefore the maintaining effect can be particularly improved. Furthermore, since the polyhydric alcohol is liquid at room temperature, it can be prevented from solidifying and becoming a contaminant. In this case, the hydroxyl value of the polyethylene glycol is preferably at least 200. In this case, compatibility with water is further improved, making it possible to further enhance the stain prevention and maintenance effects.

[0017] As described above, the stain inhibitor composition of the present invention has excellent stain prevention effect and its durability, and is therefore suitably used in applications in which the composition is applied to an upstream roll located on the upstream side of multiple rolls (e.g., a dryer roll or a canvas roll) in a dry part to form a liquid coating, a running body is brought into contact with the liquid coating to transfer a part of the liquid coating to the running body, and the running body is brought into contact with a downstream roll located downstream of the upstream roll to transfer the liquid coating to the downstream roll. In addition, when the polyhydric alcohol is liquid at room temperature, the amount of transfer to the traveling body (hereinafter also referred to as "pickup amount") is improved, and the maintenance effect on the downstream roll is also excellent.

[0018] In this case, when the contact angle, viscosity, dynamic surface tension, and moisture content of the running body when contacting the upstream roll and downstream roll, which are made of cast iron, of the antifouling agent composition are all within the above-mentioned ranges, a liquid coating is easily formed on the rolls and the liquid coating is easily transferred to the running body, making the antifouling agent composition more suitable for the above-mentioned applications. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic diagram illustrating a dry part in which the stain-proofing composition according to this embodiment is used. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. Positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

[0021] The stain inhibitor composition according to the present embodiment is a liquid agent for preventing staining, and is applied to the dry part of the papermaking process. Specifically, it is applied to, for example, a roll constituting the dry part (for example, a dryer roll or a canvas roll). Details of these will be described later. When such an anti-fouling composition is applied to a dry part, a liquid film is formed on the applied area, which prevents contaminants from adhering to the dry part and also makes it possible to disperse and remove any adhering contaminants.

[0022] The stain-proofing composition is an emulsion having an oily silicone oil that is liquid at room temperature, an aqueous medium that is liquid at room temperature, and a dispersant for dispersing the silicone oil in the aqueous medium. Generally, a large amount of water is used in the papermaking process, and therefore, in the stain inhibitor composition, an oily silicone oil having a stain-preventing effect is emulsified and used, which prevents the silicone oil from being repelled by the remaining water and failing to be applied to the dry part when the stain inhibitor composition is applied to the dry part. Therefore, when the stain-proofing composition is applied to a dry part, a liquid coating made of emulsion is formed on the surface of the applied part.

[0023] Specific examples of contaminants include pitch, paper dust, talc, clay, calcium carbonate, wood resin, and residues of chemicals used in the papermaking process (for example, starch and polyacrylamide in the case of paper strength agents, and rosin soap, alkyl ketene dimer, alkenyl succinic anhydride, polyvinyl alcohol, starch, styrene-acrylic polymers, etc. in the case of sizing agents). In this specification, the term "upstream side" refers to the upstream side of the conveyance path of the traveling body, and the term "downstream side" refers to the downstream side of the conveyance path of the traveling body. Furthermore, "room temperature" refers to 20°C ± 15°C as defined by the Japanese Industrial Standards (JIS Z 8703). In other words, being liquid at room temperature means that the material is in a liquid state when the temperature is within the range of 5 to 35°C.

[0024] The antifouling composition employs a silicone oil that is liquid at room temperature in order to disperse and remove oily contaminants. Among the silicone oils, it is preferable to use dimethyl silicone oil or modified silicone oil in which hydrogen atoms are substituted with modifying groups, from the viewpoint of anti-fouling effect. Examples of modified silicone oils include amino-modified silicone oil, epoxy-modified silicone oil, carboxy-modified silicone oil, carbinol-modified silicone oil, methacrylic-modified silicone oil, mercapto-modified silicone oil, phenol-modified silicone oil, polyether-modified silicone oil, methylstyryl-modified silicone oil, alkyl-modified silicone oil, higher fatty acid ester-modified silicone oil, fluorine-modified silicone oil, etc. These may be used alone or in combination.

[0025] Among these, from the viewpoints of anti-fouling effect, dispersibility, and versatility, the silicone oil is preferably at least one selected from the group consisting of dimethyl silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, and polyether-modified silicone oil, and amino-modified silicone oil is more preferred because it has a particularly excellent anti-fouling effect.

[0026] In the antifouling composition, an aqueous medium that is liquid at room temperature is used to emulsify the silicone oil. The aqueous medium comprises water and a polyhydric alcohol dissolved in the water. In this way, in the antifouling composition, the aqueous medium is a mixed solvent of water and a polyhydric alcohol, so that water is less likely to evaporate due to a so-called vapor pressure drop. Furthermore, polyhydric alcohols are themselves aqueous, and in liquid form hydrogen bonds between molecules in the same way as water, so that their boiling points are higher than those of other compounds of the same molecular weight.

[0027] For these reasons, when the stain inhibitor composition is applied to a heated roll (e.g., a dryer roll or a canvas roll), evaporation of the aqueous medium consisting of water and a polyhydric alcohol is suppressed, and the emulsion state can be maintained as much as possible even on the roll. Furthermore, as will be described later, when the emulsion is applied to a roll and then transferred to a traveling body, it is maintained in an emulsion state on the roll, so that a sufficient amount can be picked up.

[0028] The water used here is not particularly limited, but examples of water that can be used include tap water, industrial water, distilled water, pure water, and ion-exchanged water. Among these, from the viewpoint of minimizing the effect on the dispersibility of the emulsion, the water is preferably distilled water, pure water, or ion-exchanged water, and from the viewpoints of cost and versatility, the water is more preferably ion-exchanged water.

[0029] The polyhydric alcohol used is one that is soluble in water and has a boiling point of more than 100°C, preferably more than 200°C. If the boiling point of the polyhydric alcohol is less than 100°C, the effect of lowering the vapor pressure of water will not be obtained as compared to when the boiling point is within the above range, and the polyhydric alcohol itself has the disadvantage of being easily vaporized after being applied to the roll.

[0030] The polyhydric alcohol is not particularly limited as long as it is an organic compound having two or more hydroxyl groups in the molecule, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, polyethylene glycol, 1,2-pentanediol, hexylene glycol, glycerin, diglycerin, triglycerin, etc. These may be used alone or in combination.

[0031] Among these, the polyhydric alcohol is preferably at least one selected from the group consisting of glycerin, ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol, which is inexpensive due to its excellent versatility and has excellent compatibility with water, allowing the stain prevention and maintenance effects to be more fully exerted. Furthermore, the polyhydric alcohol is preferably glycerin or polyethylene glycol that is liquid at room temperature, as these polyhydric alcohols are less likely to penetrate into paper and have particularly excellent retention effects, and polyethylene glycol that is liquid at room temperature is more preferred from the viewpoint of ease of handling.

[0032] When the polyhydric alcohol is polyethylene glycol, the number of repeating oxyethylene units in the polyethylene glycol is preferably 3 to 15, and more preferably 3 to 10. In this case, the contribution of the polyhydric alcohol itself to maintaining the emulsion state increases, and the maintenance effect can be particularly improved. If the number of repeating oxyethylene units in the polyethylene glycol is less than 3, the composition may be more likely to penetrate into paper and may not be able to fully exhibit its retention effect, compared to when the number of repeating oxyethylene units is within the above range. On the other hand, if the number of repeating oxyethylene units in the polyethylene glycol is more than 15, there is a drawback in that the transferability of the stain inhibitor composition to paper is reduced, compared to when the number of repeating oxyethylene units is within the above range.

[0033] When the polyhydric alcohol is polyethylene glycol, the molecular weight of the polyethylene glycol is preferably 200 to 600, more preferably 200 to 400. In this case, the contribution of the polyhydric alcohol itself to maintaining the emulsion state increases, and the maintenance effect can be particularly improved. If the molecular weight of the polyethylene glycol is less than 200, it will be more likely to penetrate into paper and may not be able to fully exert its maintenance effect, compared to when the molecular weight is within the above range. On the other hand, if the molecular weight of the polyethylene glycol exceeds 600, there is a drawback in that the transferability of the stain inhibitor composition to paper will be reduced, compared to when the molecular weight is within the above range.

[0034] When the polyhydric alcohol is polyethylene glycol, the hydroxyl value of the polyethylene glycol is preferably at least 200. In this case, compatibility with water is further improved, making it possible to further exert the stain prevention and maintenance effects. If the hydroxyl value of the polyethylene glycol is less than 200, the affinity with the moisture in the paper will be reduced compared to when the hydroxyl value is within the above range, which is disadvantageous in that the transferability of the stain inhibitor composition to the paper will be reduced.

[0035] In the stain prevention composition, a dispersant is used to emulsify the silicone oil and the aqueous medium. The dispersant is not particularly limited, and may be a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or the like. Among these, the dispersant is preferably at least one selected from the group consisting of nonionic surfactants and anionic surfactants, from the viewpoint of storage stability of the emulsion.

[0036] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl thioethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene glycols, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, etc. These may be used alone or in combination.

[0037] Examples of anionic surfactants include aliphatic monocarboxylates, polyoxyethylene alkyl ether carboxylates, N-acylsarcosinates, N-acylglutamates, dialkyl sulfosuccinates, alkanesulfonates, olefinsulfonates, alkylbenzenesulfonates, naphthalenesulfonate-formaldehyde condensates, alkylnaphthalenesulfonates, N-methyl-N-acyltaurates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fat and oil sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, etc. These may be used alone or in combination.

[0038] Among these, the dispersant is preferably a nonionic surfactant, and from the viewpoint of dispersibility and storage stability, it is preferably at least one selected from the group consisting of polyoxyalkylene alkyl ethers, polyoxyalkylene fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, and polyoxyalkylene sorbitol fatty acid esters.

[0039] In the stain-proofing composition, the blending ratio of silicone oil to 1 part by mass of polyhydric alcohol is 0.5 to 50 parts by mass. If the blending ratio of silicone-based oil to 1 part by mass of polyhydric alcohol is less than 0.5 parts by mass, the anti-fouling effect will be insufficient, and if the blending ratio of silicone-based oil to 1 part by mass of polyhydric alcohol is more than 50 parts by mass, the effect of maintaining the anti-fouling effect will not be sufficient.

[0040] In the stain prevention composition, the blending ratio of water to 1 part by mass of polyhydric alcohol is 25 to 300 parts by mass. If the ratio of water to 1 part by mass of polyhydric alcohol is less than 25 parts by mass, the cost will be high and dispersibility may decrease, and if the ratio of water to 1 part by mass of polyhydric alcohol is more than 300 parts by mass, the maintenance effect will not be sufficient.

[0041] In the stain prevention composition, the blending ratio of the dispersant to 1 part by mass of the polyhydric alcohol is 0.1 to 50 parts by mass. If the blending ratio of dispersant to 1 part by mass of polyhydric alcohol is less than 0.1 parts by mass, dispersibility and storage stability will be insufficient, and if the blending ratio of dispersant to 1 part by mass of polyhydric alcohol is more than 50 parts by mass, the anti-fouling effect may be reduced.

[0042] The antifouling composition according to this embodiment contains a silicone-based oil, an aqueous medium, and a dispersant, and these are blended in the blending ratio described above, so that the antifouling effect based on the silicone-based oil is fully exerted and the effect can be fully maintained. Furthermore, since the dispersibility and storage stability are excellent, uneven application is suppressed, and the stain prevention effect can be further improved.

[0043] The stain-proofing composition has a dynamic surface tension of 25 mN / m or more at a life time of 100 milliseconds as measured by the maximum bubble pressure method. If the dynamic surface tension of the stain-proofing composition is less than 25 mN / m, dripping is likely to occur, making it difficult to form a uniform liquid coating of sufficient thickness on the roll surface. In addition, the dynamic surface tension is preferably 65 mN / m or less. If the dynamic surface tension exceeds the above range, the transfer speed to the running body tends to be slower than when the dynamic surface tension is within the above range. In this case, the amount of the liquid coating picked up by the running body becomes insufficient. The dynamic surface tension was measured in an environment of 25°C using an automatic dynamic surface tensiometer BP-D5 (Kyowa Interface Science).

[0044] The stain prevention composition preferably has a viscosity of 0.001 to 1.5 Pa·s. If the viscosity of the antifouling composition is less than 0.001 Pa s, the antifouling composition is more likely to scatter when sprayed on, and there is a risk that a sufficient amount may not be applied, compared with when the viscosity is within the above range. On the other hand, if the viscosity of the antifouling composition exceeds 1.5 Pa s, there is a disadvantage that the antifouling composition is more likely to become uneven when sprayed on, compared with when the viscosity is within the above range.

[0045] In the stain inhibitor composition, the emulsion is preferably an O / W emulsion. This has the advantage that the stain inhibitor composition has a high affinity with the moisture in the paper and is easily transferred to the paper. Another advantage is that the surface tension and viscosity are reduced, making it easier to spray.

[0046] The stain-proofing composition according to this embodiment is obtained as an emulsion by stirring and mixing a silicone oil, an aqueous medium, and a dispersant. In the stirring and mixing, a hand mixer, a homogenizer, etc. are preferably used. Dispersion may also be carried out using a dispersing machine such as a sand mill, a bead mill, or a ball mill.

[0047] As described above, when the stain-preventing composition is applied to the dry part, a liquid film is formed, thereby preventing the dry part from being stained. Furthermore, the antifouling composition is applied, for example, to an upstream roll located on the upstream side among the multiple rolls in the dry part to form a liquid coating, and by bringing the running body into contact with the liquid coating, a portion of the antifouling composition that constitutes the liquid coating is transferred to the running body, and by bringing the running body into contact with a downstream roll located downstream of the upstream roll, the antifouling composition is transferred to the downstream roll, thereby making it possible to form a liquid coating on the downstream roll.

[0048] FIG. 1 is a schematic diagram illustrating a dry part in which the stain-proofing composition according to this embodiment is used. The stain inhibitor composition is used in the dry part D of the papermaking process. The dry part D includes a plurality of cylindrical dryer rolls D1, D2, D3, D4, D5, D6, D7 and D8 (hereinafter also referred to as "D1 to D8") for heating and drying the wet paper W1, canvases K1 and K2 for pressing the wet paper W1 against the dryer rolls D1 to D8, a canvas roll KR for guiding the canvases K1 and K2, a breaker stack roll B for gently adjusting the smoothness and thickness of the dried paper W, and a calendar roll C for adjusting the smoothness and thickness of the paper W. That is, the plurality of rolls in the dry part refer to the dryer rolls D1 to D8, the canvas rolls KR, KR1, and KR2, the breaker stack roll B, and the calendar roll C.

[0049] In the dry part D, the wet paper web W is pressed against the surfaces of the dryer rolls D1 to D8 by the canvases K1 and K2. As a result, the wet paper web W adheres to the dryer rolls D1 to D8 and is simultaneously heated and dried. The temperature of the dryer is generally 30 to 120°C. Thereafter, the wet paper web W is sandwiched between breaker stack rolls B, and then the wet paper web W is densified by calender rolls C.

[0050] For example, when the rolls are dryer rolls and the traveling body is a wet paper web, the stain inhibitor composition is applied to the dryer roll D1 (upstream roll) on the upstream side of the dryer part D at the position indicated by arrow A1. The method for applying the antifouling composition is not particularly limited, and examples thereof include a shower method or a spray method in which the antifouling composition is sprayed from a distance using a spray nozzle, and a coating method in which the composition is directly applied using an applicator such as a sponge.

[0051] After the contamination inhibitor composition is applied to the dryer roll D1 at the position indicated by arrow A1, as the dryer roll D1 rotates to guide the wet paper web W1 (traveling body), a liquid coating of the contamination inhibitor composition is transferred to the wet paper web W1. As a result, a liquid coating of the stain inhibitor composition is carried by the wet paper web W1 and applied to the dryer roll D3 (downstream roll) on the downstream side to which the wet paper web W1 is guided when the wet paper web W1 comes into contact with the dryer roll D3. The same process is repeated until the paper is applied to dryer rolls D5 and D7 further downstream. Similarly, the stain inhibitor composition is applied to the upstream dryer roll D2, and then applied to the downstream dryer rolls D4, D6, and D8 via the wet paper.

[0052] When the plurality of rolls are canvas rolls and the traveling body is a canvas, the stain inhibitor composition is applied to the canvas roll KR1 upstream of the dry part D at the position indicated by arrow A2. The method for applying the antifouling composition is not particularly limited, and examples thereof include a shower method or a spray method in which the antifouling composition is sprayed from a distance using a spray nozzle, and a coating method in which the composition is directly applied using an applicator such as a sponge.

[0053] After the stain-preventing composition is applied to the canvas roll D1 at the position indicated by arrow A2, as the canvas roll KR1 rotates to guide the canvas K1 (traveling body), a liquid coating of the stain-preventing composition is transferred to the canvas K1. The liquid coating of the antifouling composition is then carried by the canvas K1, guided along the canvas K1, and applied to the canvas roll KR (downstream roll) inside the loop as it comes into contact with it. In the same manner, the stain-proofing composition is applied to the canvas roll KR2 outside the loop.

[0054] As described above, the stain-preventing composition is an emulsion of a silicone oil and a polyhydric alcohol that is difficult to vaporize under specific conditions, and therefore has excellent stain-preventing effect and durability. For this reason, the stain-preventing composition can be suitably used in applications where the stain-preventing composition is applied to the entire surface of dryer rolls D1 to D8 or canvas rolls KR, KR1, and KR2 by repeated transfer and application.

[0055] In the above applications, cast iron is used for the dryer rolls D1 to D8 or the canvas rolls KR, KR1, and KR2. The cast iron is a cast alloy containing iron as the main component and at least one element selected from the group consisting of nickel, chromium, carbon, and silicon. Furthermore, the cast iron preferably has a ten-point mean roughness (Rz) of 0.16 μm or less, a maximum height (Rmax) of 0.21 μm or less, and an arithmetic mean roughness (Ra) of 0.04 μm or less.

[0056] In this case, the contact angle of the stain inhibitor composition with the dryer rolls D1 to D8 or the canvas rolls KR, KR1, KR2 is preferably 70° or less, which makes it possible to instantly form a coating on the roll surface. Furthermore, if the contact angle of the antifouling composition with respect to cast iron exceeds 70°, it becomes more difficult to form a uniform liquid coating compared to when the contact angle is within the above range. The contact angle was measured using a DropMaster DMs-401 and a Teflon needle of 18G in an environment of 25°C and 50% humidity.

[0057] Furthermore, the moisture content of the wet paper web W1 (traveling body) when it comes into contact with the dryer rolls D1 to D8 is preferably 8 to 55%, where the moisture content is the ratio of the weight of water to the total weight of the wet paper web W1 containing moisture. If the moisture content of the wet paper W1 is less than 8%, the liquid coating may be absorbed, and a sufficient amount of the anti-contamination agent composition may not be applied to the downstream dryer roll, compared to when the moisture content is within the above range.If the moisture content of the wet paper W1 exceeds 55%, the amount of the anti-contamination agent composition picked up tends to be insufficient, compared to when the moisture content is within the above range. The moisture content of the wet paper web W1 can be adjusted by the conveying speed of the wet paper web in the wire part, the pressing pressure of the press roll in the press part, and the like.

[0058] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.

[0059] The stain inhibitor composition according to the present embodiment may contain additives such as a chelating agent, a pH adjuster, a preservative, a viscosity adjuster, a solid lubricant, a wetting agent, an anti-dusting agent, a release agent, an adhesive, a surface modifier, a detergent, a paper strength agent, a sizing agent, a retention aid, an anti-slip agent, and a softener.

[0060] In the stain inhibitor composition according to this embodiment, the stain inhibitor composition is applied to a dryer roll or a canvas roll in the dry part, but is not limited thereto. It may be applied directly to the canvas, or alternatively, it may be applied directly to the calender roll C, the breaker stack roll B, or the like.

[0061] In the stain inhibitor composition according to this embodiment, the roll is made of cast iron, but it may be made of another material. [Example]

[0062] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0063] (1) Experiments on aqueous media (Examples 1 to 9 and Comparative Examples 1 and 2) As the aqueous medium, ion-exchanged water (water) and the compounds shown in Table 1 were used. The silicone oil used was amino-modified silicone oil (silicone oil). Polyoxyethylene alkyl ether (nonionic surfactant) was used as the dispersant. These were mixed so that the compound shown in Table 1 was 1 part by mass, amino-modified silicone oil was 10 parts by mass, ion-exchanged water was 36.5 parts by mass, and polyoxyethylene alkyl ether was 2.5 parts by mass to obtain a sample of the antifouling agent composition. In Table 1, "PEG" means polyethylene glycol, "Gr" means glycerin, "EG" means ethylene glycol, "DEG" means diethylene glycol, and "TEG" means triethylene glycol.

[0064] (Table 1) TIFF0007762365000001.tif82151

[0065] (2) Experiments on blending ratio (Examples 10 to 31 and Comparative Examples 3 to 8) As the aqueous medium, ion-exchanged water (water) and polyethylene glycol (boiling point 200, number of EO repeats 9, hydroxyl value 280) of Example 4 were used. The silicone oil used was amino-modified silicone oil (silicone oil). Polyoxyethylene alkyl ether (nonionic surfactant) was used as the dispersant. These were mixed in the proportions shown in Table 2 to obtain samples of antifouling compositions. In Table 2, "Am" means amino-modified silicone oil, and "POE" means polyoxyethylene alkyl ether.

[0066] (Table 2) TIFF0007762365000002.tif168146

[0067] (evaluation) The samples obtained in Examples 1 to 31 and Comparative Examples 1 to 8 were sprayed at 400 μg / m on a predetermined dryer roll of an operating paper machine using a Mist Runner (spraying device, manufactured by Mentec Co., Ltd.). 2 It was sprayed so that the result was as follows. After one week had passed, the amount of dirt adhering to the dryer roll was visually evaluated. The results are shown in Table 3. In Table 3, "A" indicates a state in which no dirt (pitch or paper powder) adhered to the surface of the dryer roll, "B" indicates a state in which dirt (pitch or paper powder) adhered to about 10% of the surface of the dryer roll, "C" indicates a state in which dirt (pitch or paper powder) adhered to about 10-30% of the surface of the dryer roll, and "D" indicates a state in which dirt (pitch or paper powder) adhered to about 30-40% of the surface of the dryer roll.

[0068] (Table 3) TIFF0007762365000003.tif118161

[0069] From the above, it was confirmed that the samples of the anti-fouling agent compositions of Examples 1 to 31 of the present invention all have excellent anti-fouling effects compared to the samples of Comparative Examples 1 to 8, and that the effects are maintained for one week, so that they also have excellent maintenance effects. [Industrial Applicability]

[0070] The stain inhibitor composition of the present invention is used as a stain inhibitor in the dry part of the papermaking process. The stain inhibitor composition of the present invention has a sufficiently excellent stain inhibitory effect and its durability. [Explanation of symbols]

[0071] B···Breaker Stack Roll C···Calendar Roll D···Dry Part D1, D2, D3, D4, D5, D6, D7, D8... Dryer roll K1, K2... Canvas KR, KR1, KR2... Canvas roll W···Paper W1...Wet paper

Claims

1. A stain-preventing composition that is applied to the dry part of a papermaking process, An emulsion comprising a silicone oil that is liquid at room temperature, an aqueous medium that is liquid at room temperature, and a dispersant for dispersing the silicone oil in the aqueous medium, the aqueous medium comprises water and a polyhydric alcohol dissolved in the water, The boiling point of the polyhydric alcohol is greater than 100°C, the blending ratio of the silicone oil to 1 part by mass of the polyhydric alcohol is 0.5 to 50 parts by mass, the blending ratio of the water to 1 part by mass of the polyhydric alcohol is 25 to 300 parts by mass, The stain-proofing composition, wherein the blending ratio of the dispersant per 1 part by mass of the polyhydric alcohol is 0.1 to 50 parts by mass.

2. 2. The stain-proofing composition according to claim 1, wherein the polyhydric alcohol is at least one selected from the group consisting of glycerin, ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol.

3. the polyhydric alcohol is polyethylene glycol which is liquid at room temperature, 2. The stain-proofing composition according to claim 1, wherein the number of repeating oxyethylene units in the polyethylene glycol is 200 to 600.

4. 4. The stain-proofing composition according to claim 3, wherein the polyethylene glycol has a hydroxyl value of 200 or more.

5. Among the multiple rolls included in the dry part, a liquid coating is applied to an upstream roll located on the upstream side to form a liquid coating, a traveling body is brought into contact with the liquid coating to transfer a part of the liquid coating to the traveling body, and the traveling body is brought into contact with a downstream roll located downstream of the upstream roll to transfer the liquid coating to the downstream roll, the roll is a dryer roll or a canvas roll, When the roll is the dryer roll, the traveling body is a wet paper web, The stain-proofing composition according to any one of claims 1 to 4, wherein when the roll is a canvas roll, the traveling body is a canvas.

6. the upstream roll and the downstream roll are made of cast iron; a contact angle with respect to the upstream roll and the downstream roll is 70° or less; The viscosity is 0.001 to 1.5 Pa s, 6. The stain-proofing composition according to claim 5, which has a dynamic surface tension of 25 mN / m or more.

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