Release Aid

Abstract

The present invention relates to a release aid that includes at least one succinic anhydride derivative for use in a papermaking process. For example, the release aid of the present invention is particularly useful for use in a paperweb creping process. The present invention also relates to a paperweb creping method that includes a release aid comprising at least one succinic anhydride.

Claims

1. A release aid comprising an active ingredient comprising at least one succinic anhydride derivative, the succinic anhydride having the structural formula I or II or a salt thereof, ##STR00002## wherein R is an alkyl moiety or an alkenyl moiety having from 8 to 25 carbon atoms.

2. The release aid of claim 1, wherein R is an alkyl moiety or an alkenyl moiety having from 10 to 22 carbon atoms.

3. The release aid of claim 1, wherein R is an alkyl moiety or an alkenyl moiety having from 15 to 20 carbon atoms.

4. The release aid of claim 1, wherein the succinic anhydride derivative is selected from monosalts or disalts formed by the succinic anhydrides of formula I or II and monovalent or divalent cations.

5. The release aid of claim 4, wherein the succinic anhydride derivative is a disalt.

6. The release aid of claim 4, wherein the monovalent or divalent cations are selected from Na.sup.+, K.sup.+, NH.sub.4.sup.+, Mg.sup.2+, and Ca.sup.2+.

7. The release aid of claim 6, wherein the monovalent or divalent cations are selected from Na.sup.+, K.sup.+ and NH.sub.4.sup.+.

8. The release aid of claim 1, wherein the succinic anhydride derivative is lauryl succinic acid, lauryl succinic anhydride, pentadecyl succinic acid, pentadecyl succinic anhydride, hexadecyl succinic acid, hexadecyl succinic anhydride, hexadecenyl succinic acid, hexadecenyl succinic anhydride, octadecyl succinic acid, octadecyl succinic anhydride, octadecenyl succinic acid, octadecenyl succinic anhydride, dipotassium hexadecyl succinate, disodium hexadecyl succinate, dipotassium octadecyl succinate, disodium octadecyl succinate, dipotassium hexadecenyl succinate, disodium hexadecenyl succinate, dipotassium octadecenyl succinate, disodium octadecenyl succinate, or a combination thereof.

9. The release aid of claim 1, wherein the release aid is a stable aqueous emulsion, a stable aqueous solution, or a stable concentrate.

10. The release aid of claim 1, wherein the release aid further comprises a fatty acid, lecithin, alkoxylated alkylphenol, or (poly)C.sub.5-C.sub.20 alpha-olefin.

11. The release aid of claim 1, wherein the release aid further comprises an alkoxylated fatty acid.

12. The release aid of claim 1, wherein the release aid is a stable aqueous composition comprising the at least one succinic anhydride derivative, a water-soluble or water-dispersible surfactant, and water.

13. The release aid of claim 12, wherein the total proportion of the succinic anhydride derivative and the surfactant is from 1% to 99% by weight and the proportion of water is from 1% to 99% by weight.

14. The release aid of claim 12, wherein the surfactant is a sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, alkoxylated alcohol, or a combination thereof.

15. The release aid of claim 12, wherein the weight ratio of the at least one succinic anhydride derivative to the surfactant is 1:0.05 to 1:20.

16. The release aid of claim 15, wherein the weight ratio of the at least one succinic anhydride derivative to the surfactant is 1:0.5 to 1:10.

17. The release aid of claim 15, wherein the weight ratio of the at least one succinic anhydride derivative to the surfactant is 1:0.5 to 1:5.

18. The release aid of claim 1, wherein the release aid consists of the at least one succinic anhydride derivative, a water-soluble or water-dispersible surfactant, water, and a pH regulator.

19. A method of creping a paperweb, the method comprising: a) applying a release aid comprising an active ingredient comprising at least one succinic anhydride derivative to a rotating creping cylinder; b) pressing the paperweb against the creping cylinder for effective adhesion of the paperweb to the creping cylinder; and c) dislodging the paperweb from the creping cylinder with a doctor blade.

20. (canceled)

21. The method of claim 19, wherein the succinic anhydride derivative has the structural formula I or II or a salt thereof, ##STR00003## wherein R is an alkyl moiety or an alkenyl moiety having from 8 to 25 carbon atoms.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0014] FIG. 1 is a comparison of the peel effects of various release aids under the same testing conditions according to Comparative Example 1.

DETAILED DESCRIPTION OF THE INVENTION

[0015] The terms tissue paperweb, paperweb, web, paper sheet, sheet and paper product all refer to sheets of paper made by a process comprising steps of forming an aqueous papermaking furnish; depositing this furnish onto a foraminous surface, such as a Fourdrinier wire, and removing water from the furnish either by gravity or vacuum-assisted drainage. In the final step of the process, the desirable textural characteristics are imparted to the paper by means of TAD fabric or creping, or a combination thereof, and the sheet is dried. An example of a paper machine and a papermaking process that may be used in the invention is disclosed, for example, in U.S. Pat. No. 5,944,954 and WO2013070542, which are incorporated herein in their entirety by reference. In certain embodiments, the present invention is used in a tissue making process comprising preparing a slurry of fibers, forming a tissue web on a Fourdrinier wire, de-watering the tissue web in a pressing section, and creping the tissue web against a creping cylinder (e.g., Yankee dryer) using a flexible blade (e.g., creping or doctor blade). In certain embodiments, the present invention can be used to prepare a single ply or a multi-ply tissue or paper towel. However, it is to be understood that the release aid of the invention can be used in other known papermaking processes and in other known paper machines for manufacturing tissue and/or towel paper products.

[0016] The tissue may be comprised of various types of natural and synthetic fibers including wood pulps of chemical and mechanical types, vegetable fibers, recycled fibers and synthetic fibers such as polypropylene. The tissue may also be comprised of particulate fillers, such as kaolin clay, titanium dioxide, and/or calcium carbonate.

[0017] Throughout the entire specification, the term Composition is comprised of at least one component or ingredient, particularly including the release aid, concentrate, solution, emulsion and the like recited herein.

[0018] All percentages, ratios and proportions herein are by weight unless otherwise specified.

[0019] The release aid and emulsion or solution thereof according to the present invention comprises active ingredient as its main effective component. Active ingredient herein refers to the ingredient that plays a decisive role in the release performance. In the prior art, for example, CN1176655A, WO0174581, CN101184799, U.S. Pat. No. 6,562,194, U.S. Pat. No. 8,071,667 and JP2005076141, it is also mentioned that the release aid, in addition to active ingredients, may generally comprise surfactants to assist the active ingredients to form a stable emulsion or dispersion. Such surfactants differ from the active ingredients, and generally are, for example, fatty acids, alkoxylated fatty acids, alkoxylated alcohols, alkoxylated alkylphenols, sulfates and sulfonates of oils and fatty acids, sucrose and glucose esters and derivatives, as well as aliphatic esters, ethoxylated aliphatic esters and glycerol esters and the like. In principle, the surfactants and the specific examples mentioned in these references are also applicable to the present invention, and thus these references are incorporated herein in their entirety by reference.

[0020] A first aspect of the present invention provides a release aid used in paperweb creping process, comprising an active ingredient containing at least one succinic anhydride derivative.

[0021] The succinic anhydride derivative according to the present invention is selected from groups consisting of succinic anhydrides having the structural formula I or II and the corresponding salts thereof:

##STR00001##

wherein R is an alkyl moiety or an alkenyl moiety having from 8 to 25 carbon atoms. In certain embodiments, R is an alkyl moiety or an alkenyl moiety having from 10 to 22 carbon atoms. In certain embodiments, R is an alkyl moiety or an alkenyl moiety having from 15 to 20 carbon atoms. In certain embodiments, R is an alkyl moiety. In certain embodiments, the succinic anhydride derivative is a succinic acid, succinic anhydride, or a succinate salt.

[0022] In certain embodiments, it is possible to use monosalts or disalts formed by succinic anhydrides as described above and monovalent or divalent cations. Examples of suitable monovalent or divalent cations are Na.sup.+, K.sup.+, NH.sub.4.sup.+, Mg.sup.2+, Ca.sup.2+. In certain embodiments, the monovalent or divalent cations are Na.sup.+, K.sup.+ and NH.sub.4.sup.+. In certain embodiments, the succinic anhydride derivatives are succinate salts. In certain embodiments, the succinic anhydride derivatives are monosalts or disalts formed by succinic anhydride derivatives of formula II with monovalent cations such as Na.sup.+, K.sup.+ and NH.sub.4.sup.+. In certain embodiments, the succinic anhydride derivatives are disalts.

[0023] In certain embodiments, a succinic anhydride derivative or salt thereof is water soluble. In certain embodiments, at least about 1,000 mg of a succinic anhydride derivative or salt thereof is soluble in about 1 liter of water at 25? C.

[0024] In certain embodiments, during formation of disalts from succinic anhydride derivatives, two carboxyl groups can be bonded with the same or different monovalent cations, or with divalent cations. In certain embodiments, during formation of monosalts from succinic anhydride derivatives, the other free carboxyl group can further form an ester bond with appropriate hydrocarbon groups like alkyl. In certain embodiments, the succinic anhydride having an ester bond is water soluble. In certain embodiments, at least about 1,000 mg of a succinic anhydride derivative having an ester bond is soluble in about 1 liter of water at 25? C.

[0025] Nonlimiting examples of succinic anhydride derivatives are lauryl succinic acid or succinic anhydride, pentadecyl succinic acid or succinic anhydride, hexadecyl succinic acid or succinic anhydride, hexadecenyl succinic acid or succinic anhydride, octadecyl succinic acid or succinic anhydride, octadecenyl succinic acid or succinic anhydride, dipotassium or disodium hexadecyl succinate, dipotassium or disodium octadecyl succinate, dipotassium or disodium hexadecenyl succinate as well as dipotassium or disodium octadecenyl succinate.

[0026] In certain embodiments, the succinic anhydride derivative according to the present invention is used alone or in combination with one or more active ingredients in the release aid.

[0027] The succinic anhydride derivatives according to the present invention may be prepared in virtue of the methods or technologies known to the skilled person in the art, e.g. referring to Hydrogenation of maleic anhydride to succinic anhydride over CeO.sub.2 modified Ni/?-Al.sub.2O.sub.3 catalysts, INDUSTRIAL CATALYSIS, Vol. 22 No. 9, Sep. 2014.

[0028] In certain embodiments, the release aid is a stable aqueous composition comprising active ingredients containing the aforesaid at least one succinic anhydride derivative, a water-soluble or water-dispersible surfactant and water. In certain embodiments, the aqueous composition consists of active ingredients containing the aforesaid at least one succinic anhydride derivative, a water-soluble or water-dispersible surfactant and water. The aqueous composition can be a stable aqueous emulsion or a stable aqueous solution. In case of a stable aqueous solution, the composition can comprise an appropriate amount of a pH regulator such as NaOH, in addition to the active ingredient containing at least one succinic anhydride derivative, a water-soluble or water-dispersible surfactant and water.

[0029] In another embodiment, if necessary, the release aid can also be a stable concentrate composition, comprising the aforesaid active ingredient containing at least one succinic anhydride derivative, and a water-soluble or water-dispersible surfactant. In certain embodiments, the stable concentrate composition consists of the aforesaid active ingredient containing at least one succinic anhydride derivative, and a water-soluble or water-dispersible surfactant.

[0030] Thus, in certain embodiments, the release aid may consist of said at least one succinic anhydride derivative, a water-soluble or water-dispersible surfactant and water and optionally a pH regulator.

[0031] In certain embodiments, the release aid composition according to the present invention may also comprise other active ingredients including, for example, white oil, fatty acids, lecithin, alkoxylated alkylphenols, alkoxylated fatty acids and (poly)C.sub.5-C.sub.20 alpha-olefins. It should be appreciated that these other active ingredients are optionally added provided that they do not negatively affect the homogeneity and stability of products. Therefore, the proportion of the succinic anhydride derivatives may range from about 1 to 100% by weight, such as 1 to 99% by weight, 1 to 95% by weight, 10 to 95% by weight, 20 to 95% by weight, 35 to 95% by weight, 50 to 95% by weight or 60 to 95% by weight, based on the total weight of all active ingredients.

[0032] In certain embodiments, the surfactant is a water-soluble or water-dispersible surfactant, which can be nonionic, cationic, anionic, amphoteric or zwitterionic surfactants. Nonlimiting examples of surfactants include, for example, sorbitan fatty acid esters, such as sorbitan monooleate or sorbitan monolaurate, polyoxyethylene sorbitan fatty acid esters such as fatty acid esters and laurate esters, alkoxylated alcohols, other fatty acids, alkoxylated fatty acids, alkoxylated alkylphenols, sulfates and sulfonates of oils and fatty acids, sucrose and glucose esters and derivatives thereof, as well as aliphatic esters, ethoxylated aliphatic esters and glycerol esters and the like. In certain embodiments, water-soluble or water-dispersible surfactants are nonionic surfactants, for example, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, alkoxylated alcohols and the like. In certain embodiments, the polyoxyethylene sorbitan fatty acid esters can be Tween 20, Tween 40, Tween 60 and Tween 80, while the sorbitan fatty acid esters can be Span 20, Span 40, Span 60 and Span 80. In certain embodiments, an alkoxylated alcohol or ethoxylated alcohol with about 3 to 15 EO groups is used. In certain embodiments, a fatty alcohol polyoxyethylene ether is used.

[0033] As for the water-based release aid composition according to the present invention, including emulsion or solution composition, the total proportion of at least one succinic anhydride derivative and the surfactant can be set within the scope from 1% to 99% by weight and the water component can be added in an amount from 1% to 99% by weight. In certain embodiments, the water component can be added in an amount from 50% to 90% by weight. In certain embodiments, the release aid concentrate composition comprises less than 1% by weight of water. In certain embodiments, the release aid concentrate composition is essentially free of water. In addition, in the water-based release aid composition and the release aid concentrate composition, in certain embodiments, the weight ratio of said at least one succinic anhydride derivative to the surfactant is 1: (0.05 to 20). In certain embodiments, the weight ratio of said at least one succinic anhydride derivative to the surfactant is 1: (0.5 to 10). In certain embodiments, the weight ratio of said at least one succinic anhydride derivative to the surfactant is 1: (0.5 to 5).

[0034] The water-based release aid composition is prepared by adding water proportionally into the premixed mixture of the active ingredient containing succinic anhydride derivative and surfactant system, e.g., the release aid concentrate composition as described above. An emulsion with a certain range of particle size could be prepared from the water-based release aid formulation by adjusting the ratio of the water component and the surfactant.

[0035] Generally, the water-based composition will result in higher quality of coating film on the hot plate.

[0036] A second aspect of the present invention provides a novel method of creping a paperweb, comprising the steps of:

[0037] a) applying the release aid composition comprising the active ingredient containing at least one succinic anhydride derivative as described above to a rotating creping cylinder;

[0038] b) pressing the paperweb against the creping cylinder for effective adhesion of the paperweb to the creping cylinder; and

[0039] c) dislodging the paperweb from the creping cylinder with a doctor blade.

[0040] In certain embodiments, the succinic anhydride derivative provides an increase in adhesion when compared to an identical method having no succinic anhydride derivative.

[0041] In the method of creping a paperweb according to the instant invention, the release aid can be usually applied to the creping cylinder in conventional wet press machines.

[0042] In certain embodiments, about 1 to 40 mg/m.sup.2 of the release aid described herein is applied to the creping cylinder. As used herein, mg/m.sup.2 refers to the amount of succinic anhydride derivative/surfactant mixture measured in milligrams relating to the surface area of the cylinder surface to which it is applied.

[0043] The release aid composition may be applied to the creping cylinder by any suitable means, for example by spraying, to achieve uniform application of the formulation onto the cylinder. In certain embodiments, the release aid is sprayed onto a creping cylinder (e.g., Yankee dryer) using one or more spray booms. In certain embodiments, the release aid is sprayed onto a Yankee dryer as an aqueous solution or mixture prior to transfer of semi-dry tissue web.

[0044] In an embodiment, an adhesive that is also in aqueous form is applied to the Yankee dryer along with the release aid.

[0045] In certain embodiments, the release aid comprises a water-soluble, cationic polyamide-epihalohydrin (PAE) resin. The PAE resin comprises the reaction product of an epihalohydrin and a long chain polyamide containing secondary amine groups. With respect to other facets of PAE resin and some other feasible and available creping adhesives, the specification of CN101184799A may be referred to, see e.g., from line 1 page 7 to line 10 page 8 and the references cited therein. Here, CN101184799A is incorporated in the instant application in its entirety by reference.

[0046] The release aid composition of this invention may also be used in combination with functional additives used in the art to improve softness of tissue or towel. Representative functional additives include those illustrated in the 3.sup.rd paragraph on page 8 of the specification of cited CN101184799A.

[0047] A third aspect of the present invention relates to use of succinic anhydride derivative for creping paper web in a papermaking process.

[0048] In certain embodiments, a release aid comprising a succinic anhydride derivative is applied to (e.g., sprayed onto) the surface of a Yankee dryer. In certain embodiments, the creping process comprises applying a release aid comprising an active ingredient comprising at least one succinic anhydride derivative to the Yankee dryer, pressing the paperweb against the Yankee dryer, and dislodging the paperweb from the Yankee dryer with a creping blade. In certain embodiments, the succinic anhydride derivative is used in a process to form a tissue paper or paper towel.

[0049] The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

EXAMPLES

[0050] The following examples are presented for purposes of illustration and are not intended to limit the scope of the invention.

[0051] Reagents Used in Examples:

[0052] A: alkyl succinic anhydride with alkyl chain having 18 carbon atoms, octadecyl succinic anhydride

[0053] B: alkyl succinic acid with alkyl chain having 18 carbon atoms, octadecyl succinic acid

[0054] C: disodium alkyl succinate with alkyl chain having 16 carbon atoms, disodium hexadecyl succinate

[0055] D: white oil

[0056] E: tall oil fatty acid

[0057] F: water

[0058] G: Tween-80, polyoxyethylene sorbitan monooleate

[0059] H: fatty alcohol polyoxyethylene ether, AEO-5

[0060] I: 48% NaOH solution

[0061] Peeling Force Test Method

[0062] A release aid and a creping adhesive are mixed in a given proportion. The resulting mixture (3-5 mL) is taken and deposited on a surface-polished iron plate of 10 cm?20 cm in size, and then heated to 100? C. for film formation. A cotton cloth strip of 5 cm in width is immersed in water, then spread onto the iron plate and adhesively compressed. After being kept in 105? C. oven for 15 minutes, the force required for peeling the cloth strip at an angle of 180? from the iron plate is tested using a tensile tester. The more this force decreases, the better the peeling effect of the corresponding release aid is.

Example 1

[0063]

TABLE-US-00001 Release Aid Composition in the Form of an Emulsion Composition % by weight A 5% E 5% G 10% F 80%

[0064] About 5 g of A, about 5 g of E and about 10 g of G were weighed and added in a vessel. Then, the mixture was stirred at a rate of 300 RPM until a uniform liquid phase was formed. Under stirring, about 80 g of F was added slowly to the mixture forming a uniform and stable pale yellow emulsion.

Example 2

[0065]

TABLE-US-00002 Release Aid Composition in the Form of a Solution Composition % by weight B 3% C 2% H 15% F 79.9% I 0.1%.sup.

[0066] About 3 g of B, about 2 g of C and about 15 g of H as well as about 80 g of F were mixed and stirred till complete mixing, to which a small amount of I was then added to adjust the pH of the mixture to 7.5-9.0. After stirring for a while, a transparent pale-yellow solution was formed.

Example 3

[0067]

TABLE-US-00003 Release Aid Composition in the Form of a Concentrate Composition % by weight B 40% D 5% E 5% G 50%

[0068] About 40 g of B, about 5 g of D, 5 g of E and 50 g of G were weighed and added in a vessel. Then, the mixture was stirred at a rate of 300 RPM until a uniform liquid phase was formed.

Comparative Example 1

[0069] Various Release Aids:

[0070] Release aid Nalco 64575: commercially available conventional oil-based release aid

[0071] 20% emulsion type release aid (X1) was prepared analogously to Example 1, wherein the ratio of A to G was about 1:2 (5%:10%).

[0072] 20% solution type release aid (X2) was prepared analogously to Example 2, wherein the ratio of (B+C) to H was about 1:3 (5%:15%).

[0073] Concentrate type release aid (X3) was prepared analogously to Example 3, wherein the ratio of B to (E+G) was about 1:1.4 (40%:55%), and was diluted by water to the concentration of 20% prior to application.

[0074] Creping Adhesive:

[0075] Nalco 64094: PAE Adhesive

[0076] The creping adhesive and four release aids described above are formulated to four mixed solutions respectively according to the proportion of 98% adhesive to 2% each release aid. The peeling forces of different release aids were tested using the above peel force test method under the same testing conditions.

[0077] Peel effects are shown in FIG. 1. Blank referred to only creping adhesive without any release aid, and the concentration of creping adhesive therein was the same as other samples while the portion corresponding to release aids of other samples was replaced with water. As seen from the figure, under the same testing conditions, the release aid containing succinic anhydride derivatives according to the present invention enabled the peeling force to decrease the most, thereby resulting in better peel performance compared to the existing product N64575.

[0078] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0079] The use of the terms a and an and the and at least one and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term at least one followed by a list of one or more items (for example, at least one of A and B) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms comprising, having, including, and containing are to be construed as open-ended terms (i.e., meaning including, but not limited to,) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., such as) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0080] Embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.