JPS635514B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a sizing agent for warp yarns, and particularly to a fiber sizing agent that can be suitably used for spray-type sizing. Conventionally, sizing for warp threads has been done by dissolving a sizing agent such as cornstarch, polyvinyl alcohol, polyacrylic acid, or oil emulsion in water and gelatinizing it, dipping the warp threads in this to impregnate them with the sizing agent solution, and then dehydrating and drying them. This method is commonly used.
However, this sizing method not only takes a considerable amount of time for drying, but also consumes a large amount of energy especially for drying, resulting in high costs and is extremely disadvantageous industrially. In order to overcome the industrial disadvantages of such a warp sizing method, the present inventors have conducted extensive research on a convenient method of sizing, especially by spraying. We found that spray sizing can be performed accurately. That is, the present invention provides (i) a saponified product of a vinyl acetate polymer having a degree of polymerization of 100 to 1000;
40~80mol% polyvinyl alcohol resin 10~
30 parts by weight, (ii) the mixing ratio of water and alcohol is 2:8 ~
Water-alcohol mixed solvent 90 in weight range ratio of 4:6
and (iii) 0.1 to 0.5 parts by weight of a lubricant. The sizing agent component used in the sizing agent of the present invention is a partially saponified polyvinyl alcohol resin derived from a vinyl acetate polymer having a degree of polymerization of about 100 to 1000. In the present invention, the vinyl acetate polymer includes vinyl acetate homopolymers and copolymers containing vinyl acetate as a main component and other monomers that can be copolymerized with the vinyl acetate homopolymer. Such copolymerizable monomers are not particularly limited, but comonomers having a water-soluble group in the molecule, particularly preferably ethylenically unsaturated carboxylic acids, salts thereof, and amides. Examples of such unsaturated carboxylic acids include acrylic acid, methacrylic acid, crotonic acid, and itaconic acid. These salts are alkali metal salts and ammonium salts,
Practical amides include acrylamide and N-methylolacrylamide. These comonomers may be used alone or in combination of two or more.
The desirable upper limit of the ratio of introduction into the copolymer is:
Although it varies depending on the type of comonomer, it is generally 10 mol% or less. The partially saponified polyvinyl alcohol resin used in the sizing agent of the present invention is prepared by saponifying a vinyl acetate polymer having a degree of polymerization of 100 to 1000 as described above. When the degree of polymerization of the polymer is less than 100,
The binding force of the sized yarn is low, and if it exceeds 1000, it becomes difficult to perform sizing by spraying, which is not preferable. Desired degree of polymerization is 200-500
is within the range of Further, the degree of saponification of the vinyl acetate polymer is selected from the range of 40 to 80 mol%. If the degree of saponification is less than 40 mol%, the sizing thread becomes sticky and desizing becomes difficult, which is not preferable. Moreover, if it exceeds 80 mol%, it is disadvantageous because it cannot be dissolved in a water-alcohol mixed solvent having a specific mixing range ratio for dissolving it. but,
This degree of saponification varies slightly in vinyl acetate polymers containing water-soluble comonomers as copolymerization components, but even taking these into consideration, the preferred degree of saponification is 50 to 70 mol%. . The solvent used in the sizing agent of the present invention is
Mixing ratio of water: hydrating alcohol is 2:8 to 4:6
It is desirable that the drying ratio be within the range of 0.5 to 1.0, and it is important that rapid and effective drying be achieved, especially in spray sizing. If the alcohol content exceeds this ratio, it will be difficult to form a solution of partially saponified polyvinyl alcohol resin, which is desirable as a sizing agent, and if the water content is too large, drying will be hindered, which is not preferable. The alcohol used in the mixed solvent of the present invention is a lower alcohol that is mutually soluble in water, and includes, for example, methyl alcohol, ethyl alcohol, and isopropyl alcohol. In the present invention, it is important that the partially saponified polyvinyl alcohol resin is dissolved in a water-alcohol mixed solvent and adjusted to a concentration and viscosity suitable for spray sizing. Although such a solution composition is not critical, solution proportions ranging from 10 to 30 parts by weight of resin to 90 to 70 parts by weight of mixed solvent are very commonly and practically advantageously employed. In addition, in the present invention, the above solution includes
The lubricant is added in an amount of 0.1 to 0.5 parts by weight per 100 parts by weight. Such lubricants include, for example, polyether-modified silicone, polyethylene glycol, paraffin emulsion, etc. The sizing agent of the present invention includes water- and alcohol-compatible lubricants such as polyether-modified silicone and highly polymerized polyethylene glycol. Good substances are preferably used as lubricants. If the amount of the lubricant used is less than 0.1 parts by weight, it is not preferable because it causes poor slippage of the threads and deteriorates the dividing property between the threads. Moreover, if it exceeds 0.5 parts by weight, the conjugation strength will be reduced, which is industrially disadvantageous. Preferably, 0.2 to 0.4 parts by weight are added. Furthermore, other additives commonly used in sizing agents, such as a fungicide and an antifoaming agent, can also be used in the fiber sizing agent of the present invention, if necessary. The fiber sizing agent according to the present invention can be sized by spraying, and the yarn can be easily dried.In particular, the fiber sizing agent according to the present invention can be spray sized during weaving, compared to the conventional sizing method that involves impregnation, dehydration, and drying. , it is highly desirable to have a significantly improved gluing method that can be implemented industrially. Next, the present invention will be explained in more detail with reference to Examples. Example 1 15 parts by weight of a partially saponified polyvinyl alcohol resin with a saponification degree of 65 mol %, obtained by saponifying polyvinyl acetate with a polymerization degree of 350, was added and dissolved in 85 parts by weight of a mixed solvent of water:methyl alcohol at a weight ratio of 3:7. A sizing liquid was prepared by adding 0.1 part by weight of polyether-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd., KF-352) as a lubricant. When we put this preparation into a hand sprayer and sprayed it while weaving 20 # of 100% polypropylene fibers, weaving was extremely efficient. Furthermore, when 100% polyester was sized to 75° using the slusher method, the sizing speed could be increased from the conventional 60 Y/min to 120 Y/min, and the weaving was also good. Examples 2 to 4 and Comparative Examples 1 to 4 Sizing was performed in exactly the same manner as in Example 1, except that various different sizing agents were used. The contents of each fiber sizing agent are shown in Table 1, and the results of experiments using them are summarized in Table 2.

【table】

[Table] In the specific example, the experiment was carried out on polypropylene fiber, which is the most difficult to size, so slightly unsatisfactory experimental results were observed even with the sizing agent of the present invention, but fully satisfactory results were confirmed for other fibers. ing. It can also be seen that it is desirable to introduce selected comonomers to fibers that are difficult to glue.

Claims (1)

[Scope of Claims] 1 (i) A partially saponified polyvinyl alcohol resin having a saponification degree of 40 to 80 mol%, which is a saponified product of a vinyl acetate polymer having a polymerization degree of 100 to 1000.
10 to 30 parts by weight, (ii) a water-alcohol mixed solvent with a mixing ratio of water and alcohol in a weight range of 2:8 to 4:6;
90 to 70 parts by weight; and (iii) 0.1 to 0.5 parts by weight of a lubricant.