ANTI-CONTAMINATION AGENT COMPOSITION

Abstract

[Problem] To provide a contamination preventing agent composition capable of effectively preventing pitch contamination in a dry part. [Solution] The present invention relates to a contamination preventing agent composition for preventing pitch contamination in a dry part D of a papermaking process, the composition containing: a linear polysiloxane compound represented by formula (1); and a cyclic siloxane compound. [In formula (1), a substituent R.sup.1 represents, in the same molecule, a hydrogen atom, an alkyl group, a methylphenyl group, a polyether group, a higher fatty acid ester group, an amino-modified group, an epoxy-modified group, a carboxylic group, a phenol group, a mercapto group, a carbinol group, or a methacrylic group, and a repeating number n of a siloxane unit represents an integer of 20-1430.]

##STR00001##

Claims

1. An anti-contamination agent composition for preventing pitch contamination in a dry part of a paper-making process, comprising: a linear polysiloxane compound represented by following formula (1), and a cyclic siloxane compound. ##STR00006## [wherein substituents R.sup.1 represent a hydrogen atom, an alkyl group, a methylphenyl group, a polyether group, a higher fatty acid ester group, an amino-modified group, an epoxy-modified group, a carboxy group, a phenol group, a mercapto group, a carbinol group, or a methacryl group, and the number n of repeating siloxane units represents an integer from 20 to 1430].

2. The anti-contamination agent composition according to claim 1, wherein at least one of the substituents R.sup.1 in one molecule are an amino-modified group represented by following formula (2). ##STR00007## [wherein substituents R.sup.2 and R.sup.3 each independently represent an alkylene group having 1 to 6 carbon atoms, and the number m of repeating aminoalkylene units represents an integer from 0 to 2.

3. The anti-contamination agent composition according to claim 1, wherein the cyclic siloxane compound is at least one compound selected from the group consisting of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane.

4. The anti-contamination agent composition according to claim 1, wherein a blending quantity of the cyclic siloxane compound is 15 to 20,000ppm.

5. The anti-contamination agent composition according to claim 1, wherein a blending mass ratio of the cyclic siloxane compound and the polysiloxane compound is 1:5 to 50,000.

6. The anti-contamination agent composition according to claim 1, wherein the anti-contamination agent composition further containing an emulsifier and water is emulsion having a median diameter of 0.01 to 5.0 m.

7. (canceled)

8. The anti-contamination agent composition according to claim 1, wherein the anti-contamination agent composition is applied to the cast-iron drier roll in the dry part, the anti-contamination agent composition having a surface tension of 65 mN/m or less, and having a contact angle to the drier roll of 80 or less.

9. The anti-contamination agent composition according to claim 1, wherein the anti-contamination agent composition is applied to the polyester canvas in the dry part, the anticontamination agent composition having a surface tension of 65 mN/m or less, and having a contact angle to the canvas of 80 or less.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 is a schematic diagram showing a dry part to which the anti-contamination agent composition according to the present invention is applied.

DESCRIPTION OF EMBODIMENTS

[0037] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawing as necessary. It should be noted that the vertical and horizontal positional relations are, unless otherwise stated, based on the positional relations shown in the drawing. In addition, the dimensional ratios are not limited to the ratios illustrated in the drawing.

[0038] The anti-contamination agent composition according to the present invention, which is applied to a dry part in a paper-making process, can prevent the dry part from being contaminated with pitch. (hereinafter, referred to as pitch contamination).

[0039] The dry part includes devices such as a drier roll, a canvas, a canvas roll, a calender roll, and a breaker stack roll. The details of the dry part will be described later.

[0040] The anti-contamination agent composition according to the present invention contains a linear polysiloxane compound, a cyclic siloxane compound, an emulsifier, and water.

[0041] When the anti-contamination agent composition. is applied to the dry part, the polysiloxane compound forms a film on the surface of the dry part and thereby exerts the pitch adhesion preventing effect.

[0042] At this time, the coexisting cyclic siloxane compound exerts the pitch dispersing effect.

[0043] By these actions, the anti-contamination agent composition can effectively prevent pitch contamination in the dry part.

[0044] The anti-contamination agent composition is an. emulsion, in which an oleaginous polysiloxane compound and cyclic siloxane compound, and aqueous water are emulsified by an emulsifier.

[0045] The emulsion preferably has a median diameter of 0.01 to 5.0 m. In this case, even if the composition is a mixture of the poiysiioxane compound and the cyclic siloxane compound, both compounds have an excellent sequential dispersion. stability.

[0046] If the median diameter is less than 0.01 m, the water resistance of a formed film may deteriorate as compared with the case of the median diameter being in the above range. If the median diameter is greater than 5.0 m, the emulsion stability may deteriorate as compared with the case of the median diameter being in the above range.

[0047] When the anti-contamination agent composition is applied to a cast-iron drier roll, its zeta potential is preferably 90 to 10, or +10 to +90. In other words, it is preferably 10 to 90 in absolute value. In this case, the composition has an advantage of being readily fixed onto the surface of the drier roll due to the electric action.

[0048] If the zeta potential is less than 10 in absolute value, the adsorptivity of the anti-contamination agent composition to the drier roll surface and the emulsion stability may deteriorate, as compared with the case of the zeta potential being in the above range. If the zeta potential is greater than 90 in absolute value, the adsorptivity of the anti-contamination agent composition to the drier roll surface is likely excessive, causing insufficient transfer of the anti-contamination agent composition to a wet paper sheet, as compared with the case of the zeta potential being in. the above range. It should be noted, as described later, transfer of a proper quantity of the anti-contamination agent. composition to the wet paper sheet enables the anti-contamination. agent composition to retransfer to a downstream dry part with which the wet paper sheet will come into contact.

[0049] Likewise, when the anti-contamination agent composition is applied to a polyester canvas, its zeta potential is preferably 90 to 10, or +10 to +90. In other words, it is preferably 10 to 90 in absolute value. In this case, the composition has an advantage of being readily fixed onto the surface of the canvas due to the electric action.

[0050] If the zeta potential is less than 10 in absolute value, the adsorptivity of the anti-contamination agent composition to the surface of the canvas and the emulsion stability may deteriorate, as compared with the case of the zeta potential being in. the above range. If the zeta potential is greater than 90 in absolute value, the adsorptivity of the anti-contamination agent composition to the surface of the canvas is likely excessive, causing insufficient transfer of the anti-contamination agent composition to a wet paper sheet, as compared with the case of the zeta potential being in the above range. It should be noted, as described later, transfer of a proper quantity of the anti-contamination agent composition to the wet paper sheet. enables the anti-contamination agent composition to retransfer to a downstream dry part with which the wet paper sheet will come into contact.

[0051] When the anti-contamination agent composition is applied to a cast-iron drier roll, its surface tension (dynamic surface tension at a lifetime of 100 milliseconds measured by a maximum bubble pressure method) is preferably 65 mN/m or less. In this case, the composition has an advantage of being readily fixed onto the surface of the drier roll.

[0052] If the surface tension is greater than 65 mN/m, the growth rate of film forming onto the drier roll surface may decrease, causing insufficient formation of a film, as compared. with the case of the surface tension being in the above range.

[0053] It should be noted that the value of the surface tension was measured at 25 C. by using an automatic dynamic surface tensiometer BP-D5 (Kyowa Interface Science).

[0054] Likewise, when the anti-contamination agent composition is applied to a polyester canvas, its surface tension (dynamic surface tension at a lifetime of 100 milliseconds measured by a maximum bubble pressure method) is preferably 65 mN/m or less. In this case, the composition has an advantage of being readily fixed onto the surface of the canvas.

[0055] If the surface tension is greater than 65 mN/m, the growth rate of film forming onto the surface of the canvas may decrease, causing insufficient formation of a film, as compared with the case of the surface tension being in the above range.

[0056] When the anti-contamination agent composition is applied to a cast-iron. drier roll, its contact angle to the drier roll is preferably 80 or less. In this case, the composition can instantly form a film on the surface of the drier roll.

[0057] It should be noted that the contact angle was measured at 25 C., 50% humidity using DropMaster DMs-401 with a Teflon needle 18G.

[0058] In addition, cast-iron used for contact. angle measurement and cast-iron for a drier roll may be either the same or different. Provided, however, both cast-iron for contact angle measurement and a drier roll preferably have a 10-point average roughness (Rz): 0.16 m or less, a maximum height (Rmax): 0.21 m or less, and an. arithmetic average roughness (Ra): 0.04 m or less.

[0059] Likewise, when the anti-contamination. agent composition is applied to a polyester canvas, its contact angle to the canvas is preferably 80 or less. In this case, the composition can instantly form a film on the surface of the canvas.

[0060] In the anti-contamination agent composition, the polysiloxane compound is linear, which is represented by following formula (1).

##STR00004##

[0061] In the polysiloHane compound represented by formula (1), substituents R.sup.1 include a hydrogen atom, an alkyl group, a methylphenyl group, a polyether group, a higher fatty acid ester group, an amino-modified group, an epoxy-modified group, a carboxy group, a phenol group, a mercapto group, a carbinol group, and a methacryl group, etc. It should be noted that substituents R.sup.1 may be either all the same or different from. each other in one molecule.

[0062] In addition, in the anti-contamination agent composition, the polysiloxane compounds having different substituents R.sup.1 may be mixed.

[0063] In particular, substituents R.sup.1 are preferably the methyl group (s) and/or the amino-modified group (s), and more preferably reactive amino-modified groups in one molecule of the porysiloxane compound in terms of the holding power of a film on a drier roll surface.

[0064] Here, the epoxy-modified group includes an epoxy alkyl group or an epoxy polyether group.

[0065] In addition, the amino-modified group is represented by following formula (2).

##STR00005##

[0066] In the amino-modified group represented by formula (2), substituents R.sup.2 and R.sup.3 are each independently an alkylene group having 1 to 6 carbon atoms.

[0067] In particular, substituents R.sup.2 and R.sup.3 in the amino-modified group are each independently an ethylene group or a propylene group in terms of the holding power of a film on a drier roll surface.

[0068] In addition, substituents R.sup.2 and R.sup.3 being different alkylene groups are preferred in terms of the holding power of a film on a drier roil surface, and specifically, substituent R.sup.2 being propylene group and substituent being ethylene group are particularly preferred.

[0069] In the amino-modified group represented by formula (2), the number m of repeating aminoalkylene units is an. integer from 0 to 2. It should be noted, if the number m of repeating aminoalkylene units is 0, the amino-modified group has no substituent R.sup.2.

[0070] If the number m of repeating aminoalkylene units is greater than 3, the holding power of a film on a drier roll surface may decrease, causing deterioration of the pitch adhesion preventing effect.

[0071] In particular, the number m of repeating aminoalkylene units in the amino-modified group is preferably 1.

[0072] In the anti-contamination agent composition, the number of the amino-modified groups per molecule of the polysiloxane compound is preferably 0.5 to 5, and. more preferably 0.5 to 3, in. terms of the film holding power and the pitch contamination preventing effect.

[0073] If the number of the amino-modified groups is less than 0.5, the holding power of a film on a drier roll surface may decrease, causing deterioration of the pitch adhesion preventing effect, as compared with the case of the number of the amino-modified groups being in the above range. If the number of the amino-modified groups is greater than 5, ionicity increases and the anti-contamination agent composition excessively accumulates on the surface of the dry part, which disadvantageously causes increase of the stickiness of the dry part surface and thereby conversely encourages pitch to adhere to the dry part, as compared with the case of the number of the amino-modified groups being in the above range.

[0074] In the present specification, the number of the amino-modified groups per molecule of the polysiloxane compound refers to an average number of the amino-modified groups included in one molecule, which specifically represents a value obtained by dividing the total number of the amino-modified groups by the number of the molecules. In other words, if the number of the amino-modified groups per molecule is 0.1, this means that the total number of the amino-modified groups in 10 molecules is one,

[0075] In the polysiloxane compound represented by formula (1), the number n of repeating siloxane units is an integer from 20 to 1430, preferably from 50 to 1,000, and more preferably from 100 to 800.

[0076] If the number n of repeating siloxane units is less than 20, a film may be insufficiently formed. If the number n of repeating siloxane units is greater than 1430, the polysiloxane compound having high viscosity disadvantageously becomes sticky to adhere to the surface of the dry part, and thereby conversely encourages pitch to adhere to the dry part.

[0077] The polysiloxane compound has a kinematic viscosity at 25 C. that is preferably 20,000 mm.sup.2/s or less, more preferably 10,000 mm.sup.2/s or less.

[0078] If the kinematic viscosity is greater than 20,000 mm.sup.2/s, the stickiness disadvantageously increases as compared with the case of the kinematic viscosity being in. the above range, and thereby conversely encourages pitch to adhere to the dry part.

[0079] In the anti-contamination agent composition, the cyclic siloxane compound is a monomolecular compound in which siloxane units connect each other to form a cyclic structure.

[0080] Specifically, the cyclic siloxane compound is preferably at least one compound selected from. the group consisting of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane, and more preferably the at least one compound having another substituent in its molecule.

[0081] Such substituent includes an alkyl group, a methylphenyl group, a polyether group, a higher fatty acid ester group, an amino-modified group, an epoxy-modified group, a carboxy group, a phenol group, a mercapto group, a carbinol group, or a methacryl group. It should be noted that the substituent may be provided such that one molecule has either a plurality of the same substituents or a plurality of different substituents.

[0082] In particular, the substituent is preferably an amino-modified group. In other words, the cyclic siloxane compound preferably has an amino-modified group other than a methyl group in its molecule. Specifically, the cyclic siloxane compound is more preferably at least. one compound selected. from the group consisting of octamethylcyclotetrasiloxane having an amino-modified group, decamethylcyclopentasiloxane having an amino-modified group, and dodecamethylcyclohexasiloxane having an amino-modified group.

[0083] In this case, the pitch dispersing effect can be efficiently exerted.

[0084] In addition, the substituent of the cyclic siloxane compound is preferably the same as substituents R.sup.1 of the coexisting linear polysiloxane compound shown in formula (1).

[0085] In this case, the anti-contamination agent composition has an improved storage stability, due to the excellent compatibility between the cyclic siloxane compound and the linear polysiloxane compound.

[0086] In addition, more preferably, the cyolic siloxane compounds of octamethylcyclotetrasiloxane having an amino-modified group, decarnethylcyclopentasiloxane having an amino-modified group, and dodecamethylcyclohexasiloxane having an. amino-modified group are all contained in the composition.

[0087] In this case, preferably, the quantity of octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane makes up greater than or equal to 70% of the total quantity of the cyclic siloxane compounds.

[0088] In the anti-contamination agent composition, an employed emulsifier is preferably a nonionic surfactant or an anionic surfactant.

[0089] In particular, the emulsifier is preferably a nonionic surfactant, more preferably polyoxyethylene decyl ether, polyoxyethylene cetyl ether, or polyoxyethylene stearyl ether.

[0090] In this case, such emulsifiers can not only enhance the emulsion stability of the polysiloxane compound but inhibit discoloration of paper. Here, when. colored paper such as cardboard is manufactured by a paper-making machine, the use of polyoxyethylene alkyl ether having a low molecular alkyl group as an emulsifier disadvantageously causes discoloration and color spotting of the paper. However, the use of polyoxyethylene alkyl ether having an alkyl group of a decyl group, a cetyl group, or a stearyl group as an emulsifier can inhibit the discoloration.

[0091] In the anti-contamination. agent composition, the blending ratio of the polysiloxane compound is preferably 0.1 to 40% by mass, more preferably 2.0 to 20% by mass, in terms of preventing pitch adhesion.

[0092] If the blending ratio of the polysiloxane compound is less than 0.1% by mass, the anti-contamination agent composition. itself may be absorbed by a wet paper sheet before water in the anti-contamination agent composition evaporates, causing insufficient film forming, as compared with the case of the blending ratio being in the above range. If the blending ratio of the polysiloxane compound is greater than 40% by mass, the viscosity of the anti-contamination agent composition itself increases as compared with. the case of the blending ratio of the polysiloxane compound being in the above range, which makes the uniform sprayability of the composition onto a dry part surface to be poor, as well as makes the tackiness of the composition to be greater and. possibly causes tearing of a paper sheet surface.

[0093] In the anti-contamination. agent composition, the blending quantity of the cyclic siloxane compound is preferably 15 to 20,000 ppm, more preferably 80 to 10,000 ppm, still more preferably 100 to 1,000 ppm, in terms of the pitch dispersing effect to be sufficiently exerted.

[0094] If the blending quantity of the cyclic siloxane compound is less than 15 ppm, the pitch dispersing effect is disadvantageously insufficient as compared with the case of blending quantity being in the above range. If the blending quantity of the cyclic siloxane compound is greater than 20,000 ppm, the compound will excessively accumulate on the surface of the dry part as compared. with the case of blending quantity being in the above range, which disadvantageously causes increase of the stickiness of the dry part surface and thereby conversely encourages pitch to adhere to the dry part.

[0095] In the anti-contamination. agent composition, the blending mass ratio of the cyclic siloxane compound to the polysiloxane compound is preferably 1:5 to 50,000, in terms of the balance between the pitch adhesion preventing effect. and the pitch dispersing effect.

[0096] If the blending mass ratio of the polysiloxane compound relative to 1 part by mass of the cyclic siloxane compound is less than 5 parts by mass, the pitch adhesion preventing effect may be insufficient as compared with the case of the blending mass ratio being in the above range. If the blending mass ratio of the polysiloxane compound relative to 1 part by mass of the cyclic siloxane compound is greater than 50,000 parts by mass, the pitch dispersing effect may be insufficient as compared with the case of the blending mass ratio being in the above range.

[0097] In the anti-contamination agent composition, the blending ratio of the emulsifier relative to 1 part by mass of the polysiloxane compound is preferably 0.05 to 0.4 part by mass, more preferably 0.1 to 0.2 part by mass.

[0098] If the blending ratio of the emulsifier is less than 0.05 part by mass, the emulsion stability may be insufficient as compared with the case of the blending ratio of the emulsifier being in the above range. If the blending ratio of the emulsifier is greater than 0.4 part by mass, the extent of discoloration disadvantageously increases as compared with the case of the blending ratio of the emulsifier being in the above range.

[0099] Besides these components, the anti-contamination agent composition may contain additives, such as a chelating agent, a pH adjusting agent, an antiseptic agent, a viscosity adjusting agent, a lubricating agent, a wetting agent, a dusting inhibitor, a mold releasing agent, an adhesive agent, a surface modifying agent, a cleaning agent, a paper strengthening agent, a sizing agent, a yield improving agent, a water repellent agent, an oil repellent agent, an anti-slipping agent, a lubricant, and a softening agent.

[0100] Here, the above-described lubricating agent includes mineral oil, such as gear oil, drier oil, turbine oil and spindle oil; plant oil, such as coconut oil, linseed. oil, castor oil, rapeseed oil and corn oil; paraffins, such as liquid paraffin and isoparaffin; and synthetic oil, such as polyisobutylene, polybutene, maleated. polybutene, polyethylene wax and micro wax.

[0101] Next, a description is made for a method of producing the anti-contamination agent composition according to the present embodiment.

[0102] The anti-contamination agent composition is produced through a process in which the polysiloxane compound, the cyclic siloxane compound and the emulsifier are added to water and then stirred so that the polysiloxane compound and the cyclic siloxane compound are emulsified.

[0103] For the stirring process, a mixer, a homogenizer, and a mill, etc. are used, as appropriate.

[0104] Next, a description. is made for a method of using the anti-contamination agent composition in a dry part. FIG. 1 is a schematic diagram showing a dry part to which the anti-contamination agent composition according to the present invention is applied.

[0105] As shown in FIG. 1, the anti-contamination agent composition is used in a dry part D.

[0106] Dry part D is provided with a wet paper sheet W, a plurality of cylindrical drier rolls D1, D2, D1, D4, D5, D6, D7, and D8 (hereinafter, referred to as D1 to D8) for heating and drying the wet paper sheet W, canvases K1 and K2 pressing the wet paper sheet Wonto drier rolls D1 to D8, a canvas roll KR guiding canvases K1 and K2, breaker stack rolls B adjusting the smoothness and. thickness of dried paper sheet N gently, and a calender roll C adjusting the smoothness and thickness of dried paper sheet W.

[0107] In dry part D, drier rolls D1 to D8 are made of cast-iron.

[0108] Here, cast-iron is obtained by casting an alloy containing iron as a primary component and at least one substance selected from the group consisting of nickel, chromium, carbon and silicon.

[0109] In dry part D, wet paper sheet W is pressed against the surfaces of rotating drier rolls D1 to D8 by canvases K1 and K2. Wet paper sheet H is thereby leaded to adhere to drier rolls D1 to D8 so as to be simultaneously heated and. dried. Wet, paper sheet. W is subsequently sandwiched by breaker stack rolls B, and then densified by calender roll C.

[0110] In the above-described method of using the anti-contamination agent composition, as shown in FIG. 1, the anti-contamination. agent composition is directly applied. to drier rolls D1 to D8, canvases K1 and K2, breaker stack rolls B and a calender roll C of dry part D respectively at. each position indicated by arrows A.

[0111] In this process, the anti-contamination agent composition applied to dry part D transfers to wet paper sheet H in contact with dry part D, and wet paper sheet W is further conveyed to come into contact with downstream dry part D, to which the anti-contamination agent composition can retransfer. Thus, by simply applying sufficient quantity of the anti-contamination agent composition to upstream dry part D, pitch contamination in downstream dry part D, which is downstream from the composition applied region, will be probably prevented.

[0112] Here, the method of applying the anti-contamination agent composition includes, but not particularly limited to, for example, methods such as a liquid shower system and a mist spray system with a scatter nozzle, etc.

[0113] In addition, the anti-contamination agent composition may be sprayed with a scatter nozzle being slid along paper sheet. width. The anti-contamination agent composition is sprayed over a dry part, and thereby pitch contamination is prevented.

[0114] In this process, the spray quantity of the anti-contamination agent composition per unit area of a paper sheet through which the composition passes is preferably 10 to 10,000 g/m.sup.2, and more preferably 30 to 1,000 g/m.sup.2 as a solid content of the polysiloxane compound.

[0115] If the spray quantity is less than 10 g/m.sup.2, the anti-contamination agent composition insufficiently adheres to the surface of a dry part and can likely inhibit pitch adhesion insufficiently, as compared with the case of the spray quantity being in the above range. If the spray quantity is greater than 10,000 g/m.sup.2, an excess composition accumulates on the surface of a dry part, and pitch may be caught therein to increase stains or the meshes of a canvas may be clogged, as compared with the case of the spray quantity being in the above range.

[0116] Although preferred embodiments of the present invention are described above, the present invention should not be limited to the above-described embodiments.

[0117] For example, although the anti-contamination agent composition according to the present embodiments contains the linear polysiloxane compound, the cyclic siloxane compound, the emulsifier, and water, the emulsifier and water are not always required.

[0118] Although the anti-contamination agent composition according to the present embodiments is applied to the drier rolls in the dry part (see FIG. 1), the composition may be applied not only to a dry part, but to a canvas, a canvas roll, a calender roll, and a breaker stack roll, etc.

[0119] For the anti-contamination agent composition according to the present embodiments, although the drier roll is made of cast-iron, it may be made of another material.

EXAMPLE

Examples and Comparative Examples

[0120] Active components (the linear polysiloxane compound and. the cyclic siloxane compound) with the structures and. in the blending quantities shown in following Table 1 were dispersed in water to prepare samples of Examples 1 to 31 and Comparative examples 1 to 9. It should be noted that, as the linear polysiloxane compound, the compound. shown in. formula (1) was used, and as the cyclic siloxane compound, a mixture or equal quantities of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane was used.

(Evaluation 1)

[0121] For the samples from Examples 1 to 31 and Comparative examples 1 to 9, 0.5 g of pitch was added to 10 ml of each sample and then pitch dispersibility was visually evaluated, respectively.

[0122] In the evaluation, a sample in which greater than or equal to 50% of the pitch was dispersed was evaluated as , a sample in which greater than or equal to 30% and less than 50% of the pitch was dispersed as , a sample in which 0 to less than 30% of the pitch was dispersed as .

[0123] The evaluation results are shown in Table 1.

(Evaluation. 2)

[0124] The samples from Examples 1 to 31 and Comparative examples 1 to 9 were each applied to a drier roll of.sup.. a real paper-making machine so that a spray quantity per unit area was 400 g/m.sup.2, and then contamination condition caused by pitch adhering to the drier roll was visually evaluated after 1 hour, respectively.

[0125] In the evaluation, a condition in which the surface of the drier roll had no stain adhesion was evaluated as , a condition in which less than 10% of the entire surface of the drier roll had stain adhesion as , a condition in which greater than or equal to 10% and less than 30% of the entire surface of the drier roll had stain adhesion as , a condition. in which greater than or equal to 30% of the entire surface of the drier roll had stain adhesion as . It should be noted that, if the evaluation is , , or , it shows the contamination preventing effect based on the anti-contamination agent composition is exerted.

[0126] The evaluation results are shown in Table 1.

TABLE-US-00001 TABLE 1 The cyclic The linear polysiloxane compounds represented by formula (1) siloxane compounds Blending Blending quantity quantity Contamination R1 R2 R3 m (ppm) (ppm) dispersibility condition Ex. 1 All groups are methyl groups 20 100000 500 Ex. 2 All groups are methyl groups 130 100000 500 Ex. 3 All groups are methyl groups 800 100000 500 Ex. 4 All groups are methyl groups 1430 100000 500 Ex. 5 15 polyether groups per molecule, the 20 100000 500 others are methyl groups Ex. 6 15 polyether groups per molecule, the 130 100000 500 others are methyl groups Ex. 7 15 polyether groups per molecule, the 800 100000 500 others are methyl groups Ex. 8 15 polyether groups per molecule, the 1430 100000 500 others are methyl groups Ex. 9 1 amino-modified group per molecule, 20 Propylene Ethylene 1 100000 500 the others are methyl groups group group Ex. 10 1 amino-modified group per molecule, 130 Propylene Ethylene 1 100000 500 the others are methyl groups group group Ex. 11 1 amino-modified group per molecule, 800 Propylene Ethylene 1 100000 500 the others are methyl groups group group Ex. 12 1 amino-modified group per molecule, 1430 Propylene Ethylene 1 100000 500 the others are methyl groups group group Ex. 13 1 amino-modified group per molecule, 130 Methylene Ethylene 1 100000 500 the others are methyl groups group group Ex. 14 1 amino-modified group per molecule, 130 Heptylene Ethylene 1 100000 500 the others are methyl groups group group Ex. 15 1 amino-modified group per molecule, 130 Propylene Methylene 1 100000 500 the others are methyl groups group group Ex. 16 1 amino-modified group per molecule, 130 Propylene Heptylene 1 100000 500 the others are methyl groups group group Ex. 17 1 amino-modified group per molecule, 130 Ethylene 0 100000 500 the others are methyl groups group Ex. 18 1 amino-modified group per molecule, 130 Propylene Ethylene 2 100000 500 the others are methyl groups group group Ex. 19 1 amino-modified group per molecule, 130 Propylene Ethylene 1 100000 10 the others are methyl groups group group Ex. 20 1 amino-modified group per molecule, 130 Propylene Ethylene 1 100000 15 the others are methyl groups group group Ex. 21 1 amino-modified group per molecule, 130 Propylene Ethylene 1 100000 300 the others are methyl groups group group Ex. 22 1 amino-modified group per molecule, 130 Propylene Ethylene 1 100000 5000 the others are methyl groups group group Ex. 23 1 amino-modified group per molecule, 130 Propylene Ethylene 1 100000 10000 the others are methyl groups group group Ex. 24 1 amino-modified group per molecule, 130 Propylene Ethylene 1 100000 20000 the others are methyl groups group group Ex. 25 1 amino-modified group per molecule, 130 Propylene Ethylene 1 100000 30000 the others are methyl groups group group Ex. 26 1 amino-modified group per molecule, 130 Propylene Ethylene 1 500 500 the others are methyl groups group group Ex. 27 1 amino-modified group per molecule, 130 Propylene Ethylene 1 2500 500 the others are methyl groups group group Ex. 28 1 amino-modified group per molecule, 130 Propylene Ethylene 1 500000 500 the others are methyl groups group group Ex. 29 1 amino-modified group per molecule, 130 Propylene Ethylene 1 5000000 500 the others are methyl groups group group Ex. 30 1 amino-modified group per molecule, 130 Propylene Ethylene 1 25000000 500 the others are methyl groups group group Ex. 31 1 amino-modified group per molecule, 130 Propylene Ethylene 1 50000000 500 the others are methyl groups group group Comp. All groups are methyl groups 15 100000 500 X X ex. 1 Comp. All groups are methyl groups 1500 100000 500 X X ex. 2 Comp. 15 polyether groups per molecule, the 15 100000 500 X X ex. 3 others are methyl groups Comp. 15 polyether groups per molecule, the 1500 100000 500 X X ex. 4 others are methyl groups Comp. 1 amino-modified group per molecule, 15 Propylene Ethylene 1 100000 500 X X ex. 5 the others are methyl groups group group Comp. 1 amino-modified group per molecule, 1500 Propylene Ethylene 1 100000 500 X X ex. 6 the others are methyl groups group group Comp. All groups are methyl groups 1430 100000 0 X X ex. 7 Comp. 15 polyether groups per molecule, the 1430 100000 0 X X ex. 8 others are methyl groups Comp. 1 amino-modified group per molecule, 1430 Propylene Ethylene 1 100000 0 X X ex. 9 the others are methyl groups group group indicates data missing or illegible when filed

[0127] The results shown in Table 1 obviously demonstrates that the samples of Examples 1 to 31 have excellent pitch dispersibility and can sufficiently inhibit the contamination of the drier roll, as compared with Comparative examples 1 to 9.

[0128] Consequently, the anti-contamination agent composition according to the present invention can effectively prevent pitch contamination of a dry part.

INDUSTRIAL APPLICABILITY

[0129] The anti-contamination agent composition of the present invention is used by applying it to a dry past in a paper-making process. The anti-contamination agent composition of the present invention can effectively prevent pitch contamination of the dry part, which can significantly improve yield in paper manufacturing.

REFERENCE SIGNS LIST

[0130] B . . . breaker stack roll,

[0131] C . . . calender roll

[0132] D . . . dry part

[0133] D1, D2, D3, D4, D5, D6, D7, D8 . . . drier roll,

[0134] K1, K2 . . . canvas,

[0135] KR . . . canvas roll,

[0136] W. . . wet paper sheet