Composition for Sizing Agent and Process for Using the Same Composition

The present invention relates to a composition for a sizing agent comprising a mixture of a substituted alkyl succinic anhydride or a substituted alkenyl succinic anhydride or a mixture of these succinic anhydrides, phosphates of polyoxyethylene alkyl esters or phosphates of polyoxyethylene alkyl aryl ethers or a mixture of these phosphates of esters and a process for using the composition for the sizing agent by dispersing the composition in aqueous solution of aqueous soluble polymer compound, adding the obtained aqueous dispersant in a pulp slurry of paper making raw material, and making paper and, more particularly, to a composition for sizing paper having excellent storage effect and preferable underwater self emulsion, and a process for making paper having excellent sizing effect by using the composition.

There is known a sizing agent and particularly a paper making sizing agent such as a mixture homogenized by mechanically agitating an aqueous solution of cationic starch and a substituted succinic anhydride in an aqueous dispersion to be mixed with a pulp slurry, a dispersion of mixture of premixing a substituted succinic anhydride and nonionic surfactant of certain type in water (in Japanese Patent Publication No. 36044/1978), or an aqueous dispersion of a substituted succinic anhydride and underwater oil type surfactant dispersed in a substituted succinic anhydride having diameters of ultrafine particles dispersed an aqueous solution of ampholitic acrylamide polymer (in Japanese Patent Laid-open No. 45,731/1983). A large scale apparatus is required in the case of producing the dispersion by using cationic starch of these aqueous dispersions, and yet it is difficult to sufficiently finely pulverize the dispersion particles in the obtained aqueous dispersion. Therefore, the sizing agent has a drawback that the sizing effect of the dispersion is deteriorated, and the aqueous dispersions of the latter two having inadequate storage stability of the composition before the aqueous dispersion of the latter two is dispersed in the aqueous dispersion, and as time is elapsed, the under water dispersant is erased, and the sizing performance is largely decreased. Consequently, the mixture compostion must be adjusted immediately when used as the sizing agent, and there is a problem in a practical use in an industrial scale.

In order to solve the above-described problems, the present inventors have proposed an aqueous dispersion containing a surfactant having a substituted succinic anhydride and a half ester residue of the substituted succinic acid (in Japanese Patent Application No. 154984/1982), but in the aqueous dispersion, when a substituted alkenyl succinic anhydride of an additive reaction product of a straight chain internal olefin and maleic anhydride is used as the substituted succinic anhydride, sufficient underwater dispersing effect cannot be obtained unless the above-described surfactant is mixed in large quantity, and since the large quantity of the surfactant substance disturbs the sizing effect. Therefore, it is found that excellent sizing effect cannot be obtained.

Accordingly, an object of the present invention is to provide a composition for a sizing agent which exhibits excellent storage stability and underwater self-emulsion and hence excellent sizing effect comprising (a) 70-99.9 wt.% of a substituted alkyl succinic anhydride or a substituted alkenyl succinic anhydride or a mixture of these succinic anhydrides, (b) 0.1-30 wt.% of phosphates of polyoxyethylene alkenyl ether esters or phosphates of polyoxyethylene alkyl alley ether esters or a mixture of these phosphate esters, and a process for effectively making paper having excellent sizing effect by using the composition for the sizing agent, i.e., a process for using the composition for a sizing agent.

A composition for a sizing agent of the present invention comprises of (a) 70-99.9 wt.% of a substituted alkyl succinic anhydride or a substituted alkenyl succinic anhydride or a mixture of these succinic anhydrides, and (b) 0.1-30 wt.% of phosphates of polyoxyethylene alkyl ether esters or phosphates of polyoxyethylene alkyl aryl ether esters or a mixture of these phosphate esters.

A substituted alkyl succinic anhydride or a substituted alkenyl succinic anhydride in the composition for a sizing agent may empoly any of the compounds heretofore known per se as a sizing agnet, and concretely employ a substituted succinic anhydride having 8 or more carbons and preferably 12-36 alkyl group or alkenyl group. This substituted succinic anhydride can be readily produced generally by utilizing alpha-olefin, inner olefin or the additive reaction of an alpha-olefin, inner olefin or their mixture having carbon atoms of corresponding number or their mixture, and utilitzing the additive reaction of these mictures with maleic anhydride. Particularly, when the substituted succinic anhydride is, for ecample, octadecene-9, tetradecene-7, hexadecene-7, eicosane-11 or their mixtures, straight chain inner olefin mixture in which double bond produced by dehydrated reaction of a straight chain paraffin is substantially uniformly distributed at the positions except alpha-position, additive reaction product of inner olefin and maleic anhydride of straight chain inner olefin mixture having 70% or more of total amount of inner olefin disposed at 2-, 3- and 4-position of double bond produced by anisotropic reaction in the presence of a catalyst with straight alpha-olefin, i.e., substituted alkenyl succinic anhydride having succinic anhydride group in a substituted group, the sizing effect effected by the composition for the sizing agent of the present invention becomes improved.

Other phosphates of polyoxyethylene alkyl ether esters or phosphates of polycyethylene alkyl aryl ether ester are preferably compounds represented by the following general formula: ##STR1## where R is an alkyl or alkyl aryl group having 8 or more carbon atoms; A represents H or R'--(O--CH.sub.2 CH.sub.2).sub.m ; and n an integer greater than or equal to 1. In addition R' is alkyl or alkyl aryl group, m is an integer greater than or equal to 1. Particularly, when the R of the above general formula is alkyl or alkyl aryl group having 10-20 carbon atoms and the value of n is 5 or more, the underwater dispersion particles of the produced substituted succinic anhydride becomes extremely fine, and the sizing effect exhibited by the composition of the present invention becomes very excellent.

In the mixture of (b) the phosphates of esters in the same manner as (a) the substituted succinic anhydride, the mixture of (a) 70-90 wt.% of substituted succinic anhydride and (b) 10-30 wt.% of the phosphates of esters produces water dispersion containing substituted succinic anhydride of sufficiently fine particle size by merely mixing the mixture, thereby providing a so-called self-emulsion type paper making sizing agent. Further, the mixture of (a) 90-99.9 wt.% of substituted succinic anhydride and (b) 0.1-10 wt.% of the phosphates of esters disperses in aqueous solution of aqueous polymer compound in the mixture, thereby producing aqueous dispersion of substituted succinic anhydride of fine particle size sufficiently stable by mixing means of the degree for extremely slowing agitating. Therefore, when the mixture of (a) the substituted succinic anhydride and (b) the phosphates of esters is used as the paper making sizing agent, it is preferable to use aqueous disperson utilizing aqueous solution of aqueous soluble polymer compound due to the relationship pf reducing the mixture amount of (b) the phosphates of esters so as to reduced the sizing effect disturbing action caused by (b) the phosphates of esters as small as possible.

According to the present invention a process for making paper of a process for using a composition for a sizing agent comprises adding aqueous dispersion that mixture of (a) 70-99.9 wt.% of substituted alkyl succinic anhydride or substituted alkenyl succinic anhydride or their mixture of these succinic anhydrides and (b) 0.1-30 wt.% phosphates of polyoxyethylene alkyl ether esters or phosphates of polyoxyethylene alkyl aryl ether esters or their mixture of these phosphates of esters in aqueous solution of aqueous soluble polymer compound to pulp slurry of paper making material, making the paper in accordance with an ordinary method to provide paper.

In the aforementioned paper sizing process, the aqueous soluble polymer compound contained in the aqueous dispersion may employ not only cationic starch, ampholytic acrylic amide polymer heretofore known per se, but also other aqueous soluble starch derivatives, aqueous soluble cellulose derivatives, various acrylic amide polymers, polyvinylalcohol, polyethylene imine and its derivatives, aqueous soluble polyamide, aqueous soluble acrylic resin, aqueous soluble polyester, aqueous soluble maleic resin, and various aqueous soluble vinyl polymers. The aforementioned aqueous soluble polymer compounds contained in the aqueous soluble dispersion is preferably in a range of 0.1-5 Wt. parts and preferably 0.5-2 wt. parts to 1 wt. parts of substituted succinic anhydride in the aqueous soluble dispersion.

In the process for making paper of process for using a composition for a sizing agent of the present invention, various known chemicals may be used in the sizing step of adding aqueous dispersion of the sizing agent into a pulp slurry such as paper strength intensifier, filtrate accelerator, filler yield agent, fixing agent or other sizing agent. As another process, the aqueous dispersion of the produced substituted succinic acid is coated on wet paper or semidried paper by suitable known means after making or sheet making, thereby enabling surface sizing.

The composition for a sizing agent of the present invention constructed as described above consists of a mixture of specific sufactant and substituted succinic anhydride. Since the surfactant has excellent solubility to the substituted succinic anhydride, excellent storage stability is provided irrespective of the type of the substituted succinic anhydride, stable underwater self-emulsion is provided, aqueous dispersion of substituted succinic anhydride having extremely fine particle size is provided in the presence of small amount of surfactant, and excellent operation is provided as the composition for the paper making sizing agent of various types.

Since a process for making paper and a method for using the composition for the sizing agent of the present invention adds the aqueous dispersion of substituted succinic anhydride having the above-described characteristics as sizing agent in paper making pulp slurry, it can eliminate the complexity of preparing the composition immediately before using without a large scale emulsifying apparatus to produce aqueous dispersion. Therefore, it is effective to make paper having excellent sizing effect in an industrial scale.

Hereinafter, the present invention will be described further in detail by the preferred examples thereof as compared with reference examples of making paper utilizing the composition for the sizing agent and the aqueous dispersion of the composition of the present invention as the sizing agent, and the properties of the aqueous dispersion of the composition and the sizing effect of the paper will be moreover described.

Substituted alkenyl succinic anhydride and surfactant listed in predetermined columns of Table 1 are utilized, both are agitated and mixed under slow heating condition at an ambient temperature or 40.degree. C. of lower, and compositions (a), (b), (c), (d) for sizing agent of the present invention and compositions (1), (2) for comparison are prepared.

The substituted alkenyl succinic anhydride A is maleic anhydride reacted with inner olefin having 15-18 carbon atoms, and the substituted alkenyl succinic anhydride B is maleic anhydride reacted with oligomer mainly containing pentamer of propylene.

1 wt. parts of compositions (a) to (d) and (1), (2) provided in the example and comparison example are mixed with 99 wt. parts of water, agitated, dispersed to prepare aqueous dispersions of different types.

The prepared aqueous dispersions are added to 2 wt.% pulp slurry containing 20 wt.% of pulp (L-BKP, c.s.F. 400 cc) of heavy calcium carbonate filler for example, Escalon #800 made by Sankyo Powder Co.) so that the composition in the aqueous dispersion contains 0.3 wt.% of pulp, then cationic starch for example, Neo-Posiparin made by Matsutani Chemical Industry Co.) of fixing agent is added to 0.5 wt.% of pulp, paper corresponding 80 g/m.sup.2 is prepared in accordance with an ordinary process, dried in a rotary dryer of 110.degree. C. for 120 sec. to prepare paper.

The obtained paper is measured for sizing degree after moistened in accordance with JIS, and listed in Table 2.

Table 2 shows the compositions which are allowed to stand for ten days, and the results of similar test to the previous examples are listed together with emulsion mean particle size (micron) of aqueous dispersions.

Substituted alkynyl succinic anhydride and surfactant listed in predetermined columns of Table 3 are utilitzed, both are agitated and mixed under slow heating condition at an ambient temperature or of 40.degree. C. or lower, and compositions (e), (f), (g), (h) for sizing agent of the present invention and compositions (3), (4) for comparison are prepared.

The substituted alkenyl succinic anhydride A is maleic anhydride reacted with inner olefin having 15-18 carbon atoms, and the substituted alkenyl succinic anhydride B is maleic anhydride reacted with oligomer mainly containing pentamer of propylene.

Compositions (e) to (h) and (3), (4) prepared in the example 2 and comparison example 2 are filled with 5 wt.% of aqueous solution of aqueous soluble polymer compound listed in predetermined columns of Table 4, agitated at 50 V for 2 min. in a homomixer (for example, HV-M type made by Tokushu Kika Kogyo Co.), thereby preparing aqueous dispersions.

The prepared aqueous dispersions are added to 2 wt.% pulp slurry containing 20 wt.% of pulp (L-BKP, c.s.F. 400 cc) of heavy calcium carbonate filler (for example, Escalon #800 made by Sankyo Powder Co.) so that the composition of substituted alkenyl succinic anhydride and surfactant in the emulsion contains 0.5 wt.% of pulp, then cationic starch (for example, Neo-Posiparin made by Mtsutani Chemical Industry Co.) of fixing agent is added to 0.5 wt.% of pulp, paper corresponding 80 g/m.sup.2 is prepared in accordance with a known process, dried in a rotary dryer of 110.degree. C. for 120 sec. to prepare paper.

The obtained paper is measured for sizing degree after mositened in accordance with JIS, and listed in Table 4.

Table 4 shows the compositions which are allowed to stand for ten days, and the results of similar test to the previous examples are listed together with emulsion mean particle size (micron) of aquesous dispersions.