US3821075A - C21-dicarboxylic acid anhydride and size agents and sizing process - Google Patents

Abstract

There is disclosed a dicarboxylic acid anhydride made from a C21-dicarboxylic acid having the following general formula

WHEREIN X AND Y ARE INTEGERS FROM 3 TO 9, X AND Y TOGETHER EQUAL 12, WHERE Z is a member of the group consisting of hydrogen and COOH, with Z one of each moiety. There is also disclosed a process for sizing paper which comprises intimately dispersing within wet pulp, prior to the ultimate conversion of said pulp into a dry web, a sizing agent which includes a C21-dicarboxylic acid anhydride.

Description

United States Patent 1191 Bills CZI-DICARBOXYLIC ACID ANHYDRIDE AND SlZE AGENTS AND SIZING PROCESS [75 Inventor: Alan M. Bills, Summerville, S.C.

[73] Assignee: Westvaco Corporation, New York,

22 Filed: o.1s,1973

21 Appl. No.1 407,734

Related US. Application Data [63] Continuation-impart of Ser. No. 254,626, May 18,

1972, abandoned.

[52] U.S. Cl. 162/179, 162/157 C, 162/181 B, 162/181 D, 260/546 [51] Int. Cl D2111 3/08 [58] Field of Search 162/158, 179; 260/546 [56] References Cited UNITED STATES PATENTS FOREIGN PATENTS OR APPLICATIONS 1,032,363 6/1966 Great Britain 6/1964 Liggett 162/180 ,11 1 3,821,075 [4 1 June 28, 1974 Primary Examiner-S. Leon Bashore Assistant Examiner-William F. Smith Attorney, Agent, or Firm-Richard L. Schmalz; Ernest B. Lipscomb, I11

I [57] ABSTRACT There is disclosed a dicarboxylic acid anhydride made from a C -dicarboxylic acid having the following general formula 6 Claims, No Drawings 1 CZl-DICARBOXYLIC ACID ANHYDRIDE AND SIZE AGENTS ANDSIZING PROCESS CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of copending U.S. Pat. application Ser. No. 254,626, filed May 18, 1972, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the preparation of synthetic hydrophobic cellulose-reactive emulsions for sizing paper made from novel C -dicarboxylic acid anhydrides. More particularly, this invention relates to synthetic sizes made from C -dicarboxylic anhydride alone or in combination with fatty acid anhydrides or sizing agents for use in the sizing of pulp and paper products.

2. The Prior Art Paper sizing, in general, is the process of modifying a sheet of cellulose fibers to decrease the rate of penetration of a liquid. The liquid in question is normally water, but sizing against other liquids, such as oils, can be accomplished. The most common method for sizing paper against aqueous liquids is rosin sizing. In commercial rosin sizing, the rosin is added to the pulp as a dispersion in water. Sizing is obtained ,by precipitating the rosin onto the fibers. This is accomplished by adding alum and maintaining the pH of the pulp slurry within a critical pH range which is necessary to obtain good rosin sizing. Since the rosin size precipitate is only absorbed and held to the fibers by a charge difference (pulp fibers are negatively charged, rosin-size precipitate is positively charged), there remains the opportunity for the molecules to desorb when in contact with water for extended periodsof time. This phenomenon in which the rosin molecules flip" to expose their hydrophylic carboxyls to the water, allows water to penetrate into the fibers. Thus, the paper, so sized, is not permanently protected against penetration of water.

On the other hand, synthetic size becomes chemically bound to the cellulose during the drying of the paper, thus giving more permanency to the size, since the size molecules are now no longer able to flip. Synthetic size is usually added to the pulp as an emulsion in cationic starch, which also acts to retain the size on theanionic cellulose fibers. The retention can be imroved further by addition of other retention aids, such as cationic agents, to the starch emulsion. Because the size molecule forms a covalent bond with the cellulose, the synthetic size is more efficient than rosin size. Hence,

smaller quantities of synthetic size can be employed to rosion of machine parts is reduced by operating at near N neutral pH conditions.

There are, however, some major disadvantages of 1 synthetic size which includes, slipperiness of the finished paper, reduced drainage at neutral or slightly alkaline conditions thus slowing down they machine, poor availability of dyes useful at alkaline pH, and the critical threshold level of most synthetic sizes makes it viturally impossible to obtain low to moderate sizing either there is no sizing or there is hard sizing. This latter disadvantage of synthetic size has been the main reason why they have not completely replaced rosin size in applications where there is need for a low amount of sizing as in coated papers.

During the past 10 or 15 years a number of synthetic sizes have been introduced in the market place. Among these sizes include those covered by U.S. Pat. No. 3,409,500 to E. Strazdins et al. and U.S. Pat. No. 3,102,064 to O. B. Wurzburg et al. The former patent relates to distearic anhydride sizing while the latter patent relates to an alkyl substituted succinic anhydride.

It is therefore the general object of this invention to provide a new C -dicarboxylic acid anhydride. Another object of this invention is to provide improved sizing agents, whose use results in the preparation of paper which is characterized by its reduced water and ink absorption as well as its resistance to aqueous acid and alkaline solution. A more specific object of this invention is to provide a C -dicarboxylic acid anhydride paper size which gives a wide range of sizing as needed for fine paper on the one. hand and bleached board on the other hand A further object of this invention involves the use of C -dicarboxylic acid anhydridesizing agents which may be employed with a variety of types of paper pulp over a wide pH range.

Other objects, features and advantages of this invention will be evident from the foregoing detail description.

SUMMARY OF THE INVENTION q A dicarboxylic acid anhydride made from a C dicarboxylic acid having the following general formula wherein at and y are integers from 3 to 9, x and y together equal 12, where Z is a member of the group consisting of hydrogen and COOl-ll, with Z one of each moiety. A process for sizing paper which comprises intimately dispersing within wet pulp, prior to the ultimate conversion of said pulp into a dry web, a sizing agent as described above. The sizing agent may also include substantial amounts ofoleic-type acid anhydride and tall oil fatty acid anhydrides. Additionally, the sizing process may include the use of cationic agents or other materials required for emulsifying, dispersing and improving retention of the size on cellulose fibers.

DETAILED DESCRIPTION OF THE INVENTION The novel sizing agents of our invention maybe described as the anhydrideof a carboxylic acid represented by the general formula wherein x and y are integers from 3 to 9, x and y together equal 12, where Z is a member of the group consisting of hydrogen and COOl-l, with Z one of each moiety.

Although the isomers wherein x is 5 and y is 7 form a preponderance of the compositions, there are minor amounts of the C -dicarboxylic acid where the cyclohexene ring varies in position along the carbon chain. For the purpose of this specification, compositions having the general formula shown above are termed C dicarboxylic acid.

The C -dicarboxylic acids used in this invention are produced from linoleic acid of various animal, vegetable and tall oil sources. The C -dicarboxylic acid may be made by reacting linoleic acid with acrylic acid and catalytic amounts of iodine. A process for making the C -dicarboxylic acids for use in this invention as set forth in US. Pat. No. 3,753,968 granted Aug. 21, 1973. When c -dicarboxylic acids are made from tall oil fatty acids according to the process in U.S. Pat. No. 3,753,968, the reaction mixture is predominately 40 percent C ,-dicarboxylic acid and 60 percent oleic acid. This mixture of dicarboxylic acid and oleic acid may itself be converted to anhydrides and used to form the size. Another embodiment of this invention is to hydrogenate the C -dicarboxylic acid of the general formula whereby the double bond of the ring becomes saturated. There are numerous well known methods for accomplishing the hydrogenation. As another aspect of this invention, the C -dicarboxylic acid anhydrides may may be used in size emulsions with other anhydrides such as distearic anhydride.

The C -dicarboxylic acids are made into anhydrides by reacting the C -dicarboxylic acid in any number of processes using acetic anhydride, for example, as the anhydride reactant. The C -dicarboxylic acid and anhydride, a slight excess of anhydride is preferred, are mixed and heated to about the boiling point of the anhydride. The reaction is continued until all the C dicarboxylic acid has reacted. Any remaining fatty acid is stripped from the anhydride. The C -dicarboxylic acid anhydride is then made into a size emulsion by any conventional means. When other fatty acid anhydrides are included in the size, they are mixed with the C dicarboxylic acid anhydride, they may be used at from 10 percent to 90 percent by weight of the C dicarboxylic acid.

The actual use of the sizing agents of this invention in the manufacture of paper is subject to a number of variations and techniques, any of which may be further modified in light of the specific requirements of the practioner. lt is important to emphasize, however, that with all these procedures, it is most essential to achieve a uniform dispersal of the sizing agent throughout the fiber slurry, thereby necessitating that its addition to the pulp be accomplished with vigorous agitation. Uniform dispersal may also be obtained by adding the sizing agent in a fully dispersed form such as an emulsion; or, by the co-addition of chemical dispersing agents to the fiber slurry.

Another important factor in the effective utilization of the sizing agents of this invention involves their use in conjunction with a material which is either cationic in nature or is, on the other hand, capable of ionizing or disassociating in such a manner as to produce one or more cations or other positively charged moieties. These cationic agents, as they will be hereinafter referred to, have been found to be useful as means for aiding in the retention of the sizing agent as well as for bringing the sizing agent in the close proximity to the pulp fibers. Sizing processes which include cationic agents, although not a part of this invention, may beused in conjunction therewith, using the materials disclosed in the aforementioned U.S. patents, among others.

In order to obtain good sizing, it is desirable that the C -dicarboxylic acid anhydride be uniformly dispersed throughout the fiber slurry in as small a particle size as is possible to obtain. One method for accomplishing this is to emulsify the C -dicarboxylic acid anhydride prior to its addition to the stock utilizing either mechanical means, such as high speed agitators, mechanical homogenizers, or ultrasonic homogenizers, or by the addition of a suitable elulsifying agent.

With respect to amounts, the sizing agents may be employed in amounts ranging from about 0.05 to about 5.0 percent of the dry weight of the pulp in that finished sheet or web. Within this range the precise amount which is to be used will, of course, depend for the most part upon the type of pulp which is being utilized, the specific operating conditions, as well as the particular end use for which the paper is destined. Thus, for example, paper which will require good water resistance will necessitate the use of a higher concentration of siz-' ing agent than paper which will be used in applications where excessive sizing is not needed.

Water resistance of the paper prepared with C dicarboxylic acid anhydrides is obtained by drying the resulting webs, sheets or molded products. Drying involves heating the paper at temperatures in the range of from to C. for periods of from 1 to 60 minutes. The C -dicarboxylic acid anhydrides are successfully utilized for the sizing of paper prepared from all types of both cellulosic and combinations of cellulosic with noncellulosic fibers. The cellulosic fibers which may be used include bleached and unbleached sulfate (kraft), bleached and unbleached sulfite, bleached and unbleached soda, neutral sulfite, semi-chemical, chemigroundwood, ground wood, and any combination of these fibers. These designations refer to wood pulp fibers which have been prepared by means of a variety of processes which are used in the pulp and paper industry. in addition, synthetic fibers of the viscose rayon or regenerated cellulose type can also be used.

All types of pigments and fillers may be added to the paper which is to be sized with the novel C dicarboxylic acid sizing agents. Such materials include clay, talc, titanium dioxide, calcium carbonate, calcium sulfate, and diatomaceous earths. Other additives, including alum, as well as other sizing agents can also be used.

The advantages of using the C -dicarboxylic acid anhydride of the subject invention are illustrated by comparison to the effectiveness of rosin and fatty acid synthetic sizes, more particularly, the requirements of, e.g., milk carton board, coated papers, etc. For example, when using rosin size the amount of water resistance to penetration obtained is somewhat directly proportional to the amount of rosin size applied to the paper up to a limit of about 2.0 percent added rosin. On the other hand synthetic sizes are more efficient than rosin in that for a low amount of sizing, for instance, one part synthetic size may replace 3-6 parts of a fortified rosin size to obtain the same amount of water resistance. Furthermore, because synthetic sizes are not sensitive to pH they do not require additional acidic conditions and pH may be adjusted to achieve optimum machine runability and the desired paper finish characteristics. However, at low sizing levels, the degree of 5 V a synthetic distearic anhydride size, for example. From the above discussion it is easily seen that the size of this invention for particular uses has advantages that are not obtainable with either presently available synthetic sizes or rosin sizes.

The practice of this invention may clearly be seen in the following examples.

EXAMPLE 1 The following procedure is typical of that used to make C -dicarboxylic acid anhydride. One hundred fifty grams of C -dicarboxylic acid (0.532 moles) and 81.5 grams of acetic anhydride are mixed in a 500 ml. three necked flask. The mixture is heated and refluxed to just below the boiling point of acetic anhydride (130 C.) and held at that temperature. The temperature in the reflux column is maintained at the boiling point of the acetic acid. When the theoretical amount of acetic acid is collected, the reaction is stopped. The excess acetic anhydride is stripped off by distillation at reduced pressure.

EXAMPLE 2 The following procedure was used to prepare the aqueous paper-sizing C dicarboxylic acid anhydride emulsions. To 85 ml. of water was added 11.25 grams of cationic starch and cooked under constant stirring at 9597 C. for minutes. The cook was cooled to room temperature with agitation and transferred to a Monel semi-micro cup. To the cup was added 7.5 grams of a C ,-dicarboxylic acid anhydride made according to the procedure of Example 1 and the cup placed in a Waring blender and emulsified for 3 minutes. The emulsion was immediately transferred to 400 ml. of water in a one liter beaker with constant stirring. Exactly 1 liter was made by adding deionized water.

Prior to addition to the pulp furnish, the emulsion was further diluted with 9 parts water to one part emulsion. The furnish should be at or under 1.0 percent consistency. The desired quantity of diluted emulsion was added to the furnish aliquot with light agitation, and mixed for 30 seconds prior to sheet formation. The addition of 3.4 gm. of alum (dry) to the cationic starch between steps (2) and (3) gives improved resistance to penetration of highly acid test solutions.

After sheet formation 1 .25 g. TAPPl standard handsheets), the sheets were pressed according to TAPPI standard. The sheets were then drum dried for 5 minutes (2 passes) at 230 F. The sheets were conditioned at 75 F. and 50 percent relative humidity for a least 2 hours before testing with the Photosize water test. The results are shown below.

% Size on CD. Pulp Photosize Test, Sec.

The results show that the percent of sizing of this invention added to pulp may be easily controlled as shown by the slow rise in rate of sizing obtained wjile still being highly efficient. This rate and degree of sizing is particularly advantageous for making fine papers.

EXAMPLE 3 This example illustrates the sizing ability of C dicarboxylic acid anhydride mixed with 50 and percent respectively of a fatty acid, oleic-type anhydrides. The procedure for making the size emulsions was substantially the same as that used in Example 1. The results are shown below.

% Size on OD. Pulp 40% C -dicarboxylic Photosize Test The results show that both C -dicarboxylic anhydride and mixtures of the anhydride and oleic type anhydride emulsions are effective sizing agents.

EXAMPLE 4 i Three hundred (300) grams of C dicarboxylic acid and 162.5 grams of acetic anhydride were combined in a one liter flask set up with a gas inlet (N blanket) and H 0 condenser. This mixture was heated to 140 C. (pot temperature) and held at that temperature while refluxing. The temperature in the reflux column varied slightly but remained between about 1 12 C. and 130 C. The reaction was continued until 80.0 cc of acetic acid had been collected. The excess acetic anhydride was stripped off by distillation at reduced pressure and the C -dicarboxylic acid anhydride collected.

The C -dicarboxylic acid anhydride was then tested in hardwood handsheets for sizing effects. The procedure used to make aqueous paper sizing emulsions containing the C -dicarboxylic acid anhydride was that set forth in Example 2.

After sheet formation (1.30 grams TAPPI handsheets), the sheets were pressed. The sheets were then drum dried for 5 minutes (2 passes) at 230 F. The sheets were conditioned at F. and 50 percent relative humidity for at least 2 hours before testing with the Photosize water test. The results of an average of five sheets are shown below.

% Size on O. D. Pulp Photosize Test, Sec.

The results show that the percent of sizing of this invention added to pulp may be controlled.

While the invention has been described and illustrated herein by references to various specific materials, procedures and examples, it is understood that the invention is not restricted to the particular materials, combinations of materials, and procedures selected for that purpose. Numerous variations of such details can be employed, as will be appreciated by those skilled in the art.

What is claimed is:

l. Dicarboxylic acid anhydride made by reacting a C -dicarboxylic acid having the formula CH-(Clhh-COOH wherein x and y are integers from 3 to 9, x and y together equal 12, where Z is a member of the group consisting of hydrogen and COOH, with Z one of each moiety, and acetic anhydride.

2. The C dicarboxylic acid anhydride of claim 1 wherein said C -dicarboxylic acid is hydrogenated.

3. The method of sizing paper which comprises, intimately dispersing from 0.055.0 percent, based on the dry weight of the pulp, of a sizing agent within wet pulp, prior to the ultimate conversion of said pulp into a dry web, said sizing agent which comprises a C dicarboxylic acid anhydride, said C -dicarboxylic acid having the structural formula CH=CH CH3 (CHzh-C H GEL-(CH2) :14 O OH CH-CH i.

wherein x and y are integers from 3 to 9, x and y together equal 12, where Z is a member of the group consisting of hydrogen and COOH, with Z one of each moiety.

4. The method of claim 3 wherein the sizing agent is in the form of an aqueous emulsion.

5. The method of sizing paper which comprises, intimately dispersing from 005-5 .0 percent, based on the dry weight of the pulp, of a sizing agent within the wet pulp, prior to the ultimate conversion of said pulp into a dry web,

a. said sizing agent which comprises a C dicarboxylic acid anhydride, said C -dicarboxylic acid having the following formula i z Z wherein x and y are integers from 3 to 9, x and y together equal 12, where Z is a member of the group consisting of hydrogen-and COOH, with Z one of each moiety, and

b. from 10 to percent by dry weight of said C dicarboxylic acid anhydride from the group consisting of oleic acid anhydride, tall oil fatty acid anhydrides and stearic acid anhydrides.

6. A paper product having intimately dispersed with the wet pulp thereof, prior to its conversion into a dry web,

a. from 0.05-5.0 percent based on the dry weight of the pulp of a sizing agent which comprises a C dicarboxylic acid anhydride, said C -dicarboxylic acid having the structural formula,

acid anhydride and tall oil fatty acid anhydrides.

Claims (5)

1. 2. The C21-dicarboxylic acid anhydride of claim 1 wherein said C21-dicarboxylic acid is hydrogenated.
2. 3. The method of sizing paper which comprises, intimately dispersing from 0.05-5.0 percent, based on the dry weight of the pulp, of a sizing agent within wet pulp, prior to the ultimate conversion of said pulp into a dry web, said sizing agent which comprises a C21-dicarboxylic acid anhydride, said C21-dicarboxylic acid having the structural formula
3. 4. The method of claim 3 wherein the sizing agent is in the form of an aqueous emulsion.
4. 5. The method of sizing paper which comprises, intimately dispersing from 0.05-5.0 percent, based on the dry weight of the pulp, of a sizing agent within the wet pulp, prior to the ultimate conversion of said pulp into a dry web, a. said sizing agent which comprises a C21-dicarboxylic acid anhydride, said C21-dicarboxylic acid having the following formula
5. 6. A paper product having intimately dispersed with the wet pulp thereof, prior to its conversion into a dry web, a. from 0.05-5.0 percent based on the dry weight of the pulp of a sizing agent which comprises a C21-dicarboxylic acid anhydride, said C21-dicarboxylic acid having the structural formula,