JPH0556362B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Technical Field of the Invention The present invention relates to a fiber sizing agent having excellent sizing performance, particularly to a fiber sizing agent. (B) Prior art and (C) Problems to be solved by the invention Traditionally, fiber sizing agents, especially warp sizing agents, have been made using starch, polyvinyl alcohol (hereinafter sometimes abbreviated as PVA), and acrylic-based sizing agents. Polymers etc. are used. Among these, PVA is highly evaluated as a warp sizing agent due to its high film-forming properties, but it is also possible to improve the binding power of the sizing agent without reducing processability, or to increase the sizing agent without reducing performance from a cost perspective. It is desired to reduce the amount. In addition, if desizing properties are poor during weaving, uneven dyeing may occur, so improving desizing properties is also an important issue. (D) Means for Solving the Problems The present inventors have developed a PVA-based fiber sizing agent that has better binding power, and a PVA-based fiber sizing agent that still shows excellent sizing performance even when the amount of adhesive is reduced. As a result of intensive studies on PVA-based fiber sizing agent that exhibits excellent desizing properties, we found that it is a polyvinyl alcohol-based polymer that has reactive silicon groups only at the ends (terminated silicon groups).
It is sometimes abbreviated as PVA. ), it has a higher thread binding power than conventional PVA, and it has a higher thread binding strength than conventional PVA, and
It can prevent problems such as thread breakage, and even when the amount of glue is reduced, the binding strength does not decrease, making it difficult to cause problems such as fuzz and thread breakage, and it also improves desizing properties during weaving. The present inventors have also found that the present invention is excellent. The reason why the silicon-terminated PVA type adhesive of the present invention exhibits excellent sizing performance and excellent desizing properties is not fully elucidated, but it is believed to be due to the unique reactivity of the silicon-terminated group of the present invention. In other words, the terminal silicon groups do not react much when dissolved or dispersed in water as a glue, but as water is removed by drying after gluing, they react with the hydroxyl groups of the vinyl alcohol of PVA.
It is thought that some of the silicon groups react with each other, resulting in polymerization and further crosslinking. When desizing is carried out during weaving, this cross-linking bond is easily severed by water or water containing a trace amount of alkali, and the terminal silicon group reacts with the cation moiety of the alkali used to form a salt. It is thought that this makes it easier to dissolve because it becomes hydrophilic. This means that when the silicon-terminated PVA of the present invention is formed into a film alone, it crosslinks and becomes insoluble in aprotic solvents such as dimethyl sulfoxide, but the crosslinks are hydrolyzed and dissociated in water or an alkaline aqueous solution. , which is inferred from the fact that it dissolves easily. Silicon terminals with such unique reactivity
By using PVA as a fiber sizing agent, it is possible to obtain a fiber sizing agent that exhibits excellent performance as a sizing agent, has high performance even with a low amount of sizing agent, and has excellent desizing properties. The silicon-terminated PVA used in the present invention includes:
It includes all PVA-based polymers having a reactive silicon group obtained by hydrolyzing a silyl group represented by the following formula [] substantially only at the molecular end. [However, R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, more preferably a hydrocarbon group having 1 to 10 carbon atoms,
R ² is an alkoxy group, phenoxy group, alkylphenoxy group or acyloxy group having 1 to 20 carbon atoms,
(The alkoxy group, phenoxy group, alkylphenoxy group, and acyloxy group may have an oxygen-containing substituent.) n is an integer of 1 to 3. ] Here, n is preferably 3 or 2, and 3 is particularly preferred because of the high reactivity of the silicon group. By hydrolyzing the above silyl group with only alkali, acid or water, alkoxy group, acyloxy group, phenoxy group, alkylphenoxy group can be obtained.
It relatively easily becomes an OH group or OM (M is an alkali metal or ammonium group, etc.) and becomes a reactive silicon group. Here, the bond between the PVA main chain and the reactive silicon group is not particularly limited, but it is preferably a group that is difficult to decompose by hydrolysis or heating. The silicon-terminated PVA of the present invention has vinyl alcohol units.

It includes all water-soluble polymers containing the formula. Note that water-soluble in the present invention includes not only completely soluble materials but also water-dispersible materials that contain some insoluble matter but can be dispersed in water. However, in order to exhibit the effects of the present invention more efficiently, a polymer containing 50% or more of vinyl alcohol units is desirable. There are no particular limitations on component units other than vinyl alcohol units as long as the polymer is water-soluble or water-dispersible. Examples include vinyl ester units, olefin units such as ethylene and propylene, and vinyl units such as acrylic acid, methacrylic acid, or salts, amides, and esters thereof. These units can be selected depending on the type of fiber to be pasted. For example, when filament yarns are used, a binding force centered on cohesiveness is required, so a polymer containing 10 to 50 mol% of vinyl ester units is preferred to ensure particularly high flexibility and adhesiveness. . When targeting spun yarn, emphasis is placed on conjugation power, centering on fluffing ability, abrasion strength, gum up, etc. In this case, it is preferable that the vinyl ester unit contained is 0 to 30 mol%. . In addition, in addition to hydrophobic units such as vinyl ester units, carboxylic acid units or carboxylate units such as acrylic acid, methacrylic acid or their salts are used to improve the pasting performance of synthetic fibers such as polyester fibers. , amide units such as acrylamide, sulfonic acid units or salt units thereof such as 2-acrylamido-2-methylpropanesulfonic acid, trimethyl-2-(1-(meth)acrylamido-1,1-dimethylethyl)ammonium chloride, etc. It may also contain units such as cationic units. Various degrees of polymerization can be used for the silicon-terminated PVA of the present invention. However, the degree of polymerization due to the reaction of terminal silicon groups and the improvement of strength due to crosslinking are below 2000, especially below 1000. (Sakurada formula: logP=1.613×log
[η]×10 ⁴ /8.33) is more significant and preferable. However, if the degree of polymerization is too low, the efficiency of crosslinking will decrease, which is not preferable, and the degree of polymerization is preferably 50 or more. The method for producing the silicon-terminated PVA of the present invention is not limited as long as it can yield PVA in which a silicon group, obtained by hydrolyzing a silyl group, is introduced at the end of the molecule. For example, vinyl esters such as vinyl acetate are radically polymerized in the presence of a thiol compound containing a silyl group that provides the silicon group of the present invention through hydrolysis, and the resulting polyvinyl esters such as polyvinyl acetate have a silyl group at the terminal. A method of saponifying the vinyl ester unit and hydrolyzing the silyl group at the same time, or radical polymerizing vinyl esters such as vinyl acetate in the coexistence of thioacetic acid and saponifying the obtained polyvinyl esters such as polyvinyl acetate. has an HS group at the end obtained by
It can also be produced by a method in which PVA is subjected to an addition reaction with a vinyl monomer having a silyl group, such as vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, etc., and the methoxysilyl group is hydrolyzed to form a reactive silicon group. The former production method is particularly preferred because it is simple, but in order to efficiently introduce a silyl group at the end, it is desirable to maintain the concentration of the silyl group-containing thiol compound relative to the vinyl ester monomer in the polymerization system as constant as possible. Since the chain transfer constant of the thiol compound is large, for example, if the thiol compound and vinyl ester monomer are mixed and batch polymerized without adding the thiol compound afterwards, the thiol compound will be rapidly consumed and run out. As the polymerization rate progresses, a large amount of polyvinyl ester not containing a silyl group at the end is produced as a by-product. Therefore, PVA obtained by saponifying this is also undesirable because it can only yield PVA mixed with a large amount of PVA that does not have a silicon group at the end. Therefore, in order to obtain PVA in which reactive silicon groups are efficiently introduced at the terminals, the silyl group-containing thiol compound consumed during polymerization must be replenished by post-addition, and the concentration relative to the vinyl ester monomer must be kept constant. is preferred. In addition, a continuous polymerization method in which a certain amount of the thiol compound and vinyl ester are continuously supplied to the polymerization tank and the polymerization solution is continuously drawn out can also maintain a constant concentration of the thiol in the polymerization system, and This is preferable because the silyl group can be introduced efficiently. Thiol compounds with a silyl group at the end include HS group and

[Formula] [R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, more preferably a hydrocarbon group having 1 to 10 carbon atoms, R ² is an alkoxy group having 1 to 20 carbon atoms,
phenoxy group, alkylphenoxy group, or acyloxy group (herein, the alkoxy group, phenoxy group, alkylphenoxy group, or acyloxyl group may have an oxygen-containing substituent), n is 1 to 3 an integer of ] is used. For example, 3-(trimethoxysilyl)-propylmercaptan, 3-(triethoxysilyl)propylmercaptan, 2-(trimethoxysilyl)
Examples include ethyl mercaptan, 3-(dimethoxy-methylsilyl)-propyl mercaptan, 3-(monomethoxy-dimethylsilyl)-propyl mercaptan. Polymerization of vinyl esters is carried out using conventional radical polymerization initiators. During polymerization, a suitable solvent can be used for the purpose of lowering the viscosity of the polymerization system. Polymerization temperature and time can be selected as appropriate. After the polymerization is completed, the unpolymerized residual vinyl ester monomer is separated and removed, and the obtained polyvinyl ester having a silyl group at the end is saponified by a conventional method. Usually, a method of saponification in alcohol such as methanol with addition of a basic or acidic catalyst is preferred. The degree of saponification of the vinyl ester unit can be controlled by appropriately selecting saponification conditions such as the amount of catalyst, saponification time, and temperature. During this saponification reaction or when dissolving or dispersing the obtained polymer in water, the terminal

[Formula] R ² of the group is mostly hydrolyzed,

[Formula] (M is hydrogen, alkali metal, ammonium group, etc.), and PVA having a reactive silicon group at the terminal of the present invention can be obtained. A silicon-terminated PVA copolymer can be obtained by copolymerizing a copolymerizable unsaturated monomer during the polymerization of the vinyl ester and saponifying the copolymerizable unsaturated monomer. For example, ethylene, propylene, butylene,
Olefins such as α-hexene, (meth)acrylic acid, crotonic acid, (anhydrous) maleic acid, fumaric acid,
Unsaturated acids such as itaconic acid, and their alkali esters, alkali salts, (meth)acrylamide,
Sulfonic acid-containing monomers such as N,N-dimethylacrylamide, alkyl vinyl ether, 2-acrylamido-2-methylpropanesulfonic acid and their alkali salts, trimethyl-2-(1-(meth)
Examples include cationic monomers such as acrylamide-1,1-dimethylethyl)ammonium chloride. Furthermore, a small amount of a silyl group-containing unsaturated monomer such as vinyltrimethoxysilane or allyltriethoxysilane may be copolymerized. However, in this case, it is preferable to set the amount within a range that does not inhibit the water solubility of the resulting silicon-terminated PVA. In the method of copolymerizing silyl group-containing unsaturated monomers and introducing silyl groups into the main chain, the silyl groups are introduced randomly, so the content of silyl groups becomes uneven between molecules, resulting in saponified PVA. A polymer component is produced in which the amount of silicon groups introduced is larger than the average amount introduced. As a result, PVA, which contains many silicon groups in its main chain, becomes insoluble in water, probably because many reaction crosslinks are formed between the silicon groups. For this reason, it is necessary to add an alkali compound such as sodium hydroxide to break down the bonds formed by the reaction between silicon groups, which has the disadvantage of increasing the pH of the glue, so the silicon groups introduced by copolymerization are insoluble in water. It is preferable to use a small amount that does not cause A major feature of the PVA of the present invention, which has a silicon group only at the end, is that it can be dissolved only in water, which is very different from PVA in which a silicon group component is introduced into the molecular chain by copolymerization. The difference between the two can be considered as follows. In other words, in the silicon-terminated PVA of the present invention, the reaction is mainly between the reactive silicon group and the hydroxyl group of PVA.
Because there is little reaction between silicon groups, the crosslinking bonds due to silicon groups are relatively easily decomposed and dissolved in water, whereas silicon groups in copolymers are difficult to decompose even in water because there are many reactions between silicon groups. , it is thought that it has the disadvantage of being difficult to dissolve in water. There are no particular limitations on the fibers to be pasted with the fiber sizing agent made of the silicon-terminated PVA polymer of the present invention.
Suitable for use in cotton blend yarns, etc. In many cases, the fiber sizing agent made of the silicon-terminated PVA polymer of the present invention exhibits sufficient effects by itself, but if necessary, it may be combined with conventionally known sizing agents such as starch, PVA, Various modified PVA,
It may be used in combination with acrylic glue, etc. Furthermore, it is also permissible to use oil agents, antistatic agents, antifoaming agents, etc., which are usually added as auxiliaries. Although the above description has focused on the warp sizing agent, the fiber sizing agent of the present invention can also be suitably used for resin processing of textiles, laundry starch, textile printing, or as a binder for felts and nonwoven fabrics. (E) Function and Effect of the Invention The fiber glue of the present invention is a fiber glue made of PVA having a specific reactive silicon group at the terminal, and the terminal silicon group of the PVA is hardly reacted and crosslinked in the glue solution. However, when water is removed by drying, the silicon groups undergo reaction crosslinking and polymerization, resulting in excellent gluing performance, and this crosslinking is easily achieved with water or alkaline water. Since it is cut, it has the unique effect of being excellent in desizing properties. In other words, it has the characteristic of having superior gluing performance compared to conventional PVA polymers, and
It has the characteristic that higher sizing agent performance can be obtained even with a lower adhesive amount than PVA-based polymers, and it also has excellent desizing properties. As a result, PVA has a lower degree of polymerization than conventional PVA.
It has excellent fiber glue performance even when used with
It is now possible to increase the concentration of the glue during gluing,
This has the advantage of reducing moisture content, reducing drying time and costs. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto. In the examples, unless otherwise specified, "%" and "part" represent weight standards. (B) Preparation example of silicon-terminated PVA 1 2400 parts of vinyl acetate and 500 parts of methanol were charged into a reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, a reflux condenser, and a thiol compound addition device, and the mixture was stirred. After replacing the system with nitrogen, the internal temperature was raised to 60°C. To this system, 2.4 parts of 3-(trimethoxysilyl)propyl mercaptan was added (referred to as the initial addition of thiol), and a solution of 0.87 parts of 2,2'-azobisisobutyronitrile dissolved in 100 parts of methanol was added. was added to start polymerization. 27 parts of 3-(trimethoxysilyl)propyl mercaptan (hereinafter referred to as post-addition of thiol) was added continuously over 3 hours after the start of polymerization.
80 parts of a methanol solution in which was dissolved was added. After continuing the polymerization for 3 hours, the polymerization was stopped. At this point, the solid content concentration in the system was 40.9% (polymerization rate 50.1
%). After expelling unreacted vinyl acetate monomer by introducing methanol vapor, a 40% methanol solution of polyvinyl acetate having silyl groups at the ends was obtained.
While stirring a methanol solution of this polymer at 40°C, 0.8 mol% of the vinyl acetate unit was added to the methanol solution.
A methanol solution in which sodium hydroxide was dissolved was added to carry out a saponification reaction. The obtained white gel was crushed, thoroughly washed with methanol, and then dried to obtain PVA having silicon groups at the ends. The obtained PVA had a polymerization degree of 216 (calculated from Sakurada's formula) and a saponification degree of vinyl acetate units of 80.3 mol%. An aqueous solution of this silicon-terminated PVA was prepared and evaluated as a warp sizing agent for polyester fibers. The evaluation method is shown in Notes (1) to Notes in Table 1 below.
As stated in (2). The results are shown in Table 1. Example 2 A polymer with a polymerization degree of 446 and a saponification degree of vinyl acetate units of 78.5 mol % was prepared in the same manner as in Example 1, except that the initial addition amount of thiol was changed to 1.16 parts and the subsequent addition amount of thiol was changed to 13.0 parts. A silicon-terminated PVA was obtained. this
Evaluation as a warp sizing agent was conducted in the same manner as in Example 1 using PVA. The results are shown in Table 1. Example 3 A copolymer obtained by coexisting monomethyl maleate during the polymerization in Example 1 was saponified to obtain silicon-terminated PVA containing 1.2 mol % of maleic acid units. The degree of polymerization of this product determined from the intrinsic viscosity at 30°C in a 1N NaCl aqueous solution was 520, and the degree of saponification of vinyl acetate units was 79.4 mol%. Using this material, evaluation as a warp sizing agent was carried out in the same manner as in Example 1. The results are shown in Table 1. Example 4 Same as Example 1 except that 3-(diethoxy-methylsilyl)propyl mercaptan (initial addition of thiol: 1.23 parts, post-addition: 13.8 parts) was used instead of 3-(trimethoxysilyl)propyl mercaptan in Example 1. In the same manner, a silicon-terminated PVA with a polymerization degree of 451 and a saponification degree of vinyl acetate units of 79.4 mol% was obtained.
Using this PVA, evaluation as a warp sizing agent was carried out in the same manner as in Example 1. The results are shown in Table 1. Example 5 2-(monoethoxy-
Silicon-terminated PVA with a degree of polymerization of 460 and a degree of saponification of vinyl acetate units of 80.9 mol% was obtained in the same manner as in Example 1, except that dimethylsilyl)ethyl mercaptan (initial addition of thiol: 0.97 parts, post-addition of 10.9 parts) was used. Ta. Using this material, evaluation as a warp sizing agent was carried out in the same manner as in Example 1. The results are shown in Table 1. Comparative Examples 1 and 2 PVA without a silicon group at the end was prepared in the same manner as in Example 1 except that 2-mercaptoethanol was used instead of 3-(trimethoxysilyl)propyl mercaptan in Example 1, and the warp It was evaluated as a glue. The results are shown in Table 1. The PVA used in Comparative Example 1 had a degree of polymerization of 224 and a degree of saponification of 78.9 mol%, and the PVA used in Comparative Example 2 had a degree of polymerization of 450 and a degree of saponification of 81.1 mol%. Comparative Example 3 A copolymer obtained by coexisting monomethyl maleate during the polymerization of Comparative Example 1 was saponified to produce a copolymer containing 1.2 mol% of maleic acid units and having no terminal silicon groups.
PVA was prepared and evaluated as a warp sizing agent in the same manner as in Example 1. The results are shown in Table 1. PVA used
The degree of polymerization determined from the intrinsic viscosity at 30°C in a 1N NaCl aqueous solution was 524, and the degree of saponification of vinyl acetate units was 78.1 mol%. Comparative Example 3-2 PVA containing silicon groups in the molecule obtained by random copolymerization of vinyl acetate and vinyltrimethoxysilane and saponification (degree of polymerization 550, degree of saponification 98 mol%,
An evaluation test as a warp sizing agent for polyester fibers was conducted in the same manner as in Example 1 using vinyltrimethoxysilane (containing 0.4 mol%). The progress is shown in Table 1. Comparative Example 3-3 PVA containing silicon groups in the molecule obtained by random copolymerization of vinyl acetate and vinyltrimethoxysilane and saponification (degree of polymerization 550, degree of saponification 80 mol%,
An evaluation test as a warp sizing agent for polyester fibers was conducted in the same manner as in Example 1 using vinyltrimethoxysilane (containing 0.4 mol%). The results are shown in Table 1.

[Table] Note (1) Physical properties of glued yarn:

[Table] The fiber sizing agents made of silicon-terminated PVA of Examples 1 to 5 have significantly improved physical properties of the sizing threads, and have improved desizing properties compared to the fiber sizing agents of Comparative Examples 1 to 3 made of PVA. It turns out that it is also excellent. Also,
As is clear from the Examples, even when the amount of sizing is reduced, the fiber sizing agent made of silicon-terminated PVA exhibits superior physical properties of sizing threads compared to the fiber sizing agent made of ordinary PVA. In addition, compared to PVA which has silicon groups randomly in the molecule, fiber glue made of silicon-terminated PVA has
It is clear that it has excellent conjugation power and also has excellent desizing properties. Example 6 Silicon-terminated PVA with a degree of polymerization of 1690 and a degree of saponification of 92.5 mol% was prepared in the same manner as in Example 1, except that the initial charge amount of thiol in Example 1 was 0.08 parts, and the amount of thiol added later was 0.8 parts. Obtained. This aqueous solution of silicon-terminated PVA was prepared and tested for sizing on cotton yarn. The method is shown in notes (3) to (6) of Table 2 below.
As stated above. The results are shown in Table 2. Comparative Example 4 2-mercaptoethanol (initial charge: 0.03 part, post-addition: 0.34 part) was used in place of 3-(trimethoxysilyl)propyl mercaptan in Example 1 to obtain PVA having no silicon group at the end. The degree of polymerization of the obtained PVA was 1710, and the degree of saponification was 92.2 mol%. Table 2 shows the results of a sizing test on cotton yarn using this PVA in the same manner as in Example 6.
Shown below. Comparative Example 4-2 Contains a silicon group in the molecule obtained by copolymerizing vinyl acetate and trimethoxyvinylsilane and saponifying it.
Using PVA (polymerization degree 1650, saponification degree 98 mol%, vinyltrimethoxysilane content 0.25 mol%),
A sizing test on cotton yarn was conducted in the same manner as in Example 6. The results are shown in Table 2. Comparative Example 4-3 Contains a silicon group in the molecule obtained by copolymerizing vinyl acetate and trimethoxyvinylsilane and saponifying it.
Using PVA (polymerization degree 1650, saponification degree 92 mol%, vinyltrimethoxysilane content 0.25 mol%),
A sizing test on cotton yarn was conducted in the same manner as in Example 6. The results are shown in Table 2. Example 7 Using the silicon-terminated PVA used in Example 2, a sizing test on cotton yarn was carried out in the same manner as in Example 6. The results are shown in Table 2. Comparative Example 5 Using the PVA used in Comparative Example 2, a sizing test on cotton yarn was conducted in the same manner as in Example 6. The results are shown in Table 2.

[Table] As is clear from Table 2, Example 6 and Example 7
The fiber sizing agent made of silicon-terminated PVA exhibits excellent sizing yarn physical properties and desizing properties even for cotton yarn.
Also, even if the amount of glue is reduced, normal PVA
It has become clear that the physical properties of sizing threads are superior to that of fiber sizing agents made of . Furthermore, it is clear that fiber sizing agents made of silicon-terminated PVA exhibit superior sizing yarn physical properties and desizing properties even for cotton yarns, compared to PVA that contains silicon groups randomly within the molecule. .

Claims (1)

[Scope of Claims] 1. A fiber characterized by being made of a polyvinyl alcohol polymer containing a reactive silicon group obtained by hydrolyzing a silyl group represented by the following formula [1] substantially only at the molecular terminal. Gluing agent. However, R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, R ²
is an alkoxy group having 1 to 20 carbon atoms, a phenoxy group,
Alkylphenoxy group or acyloxy group,
(Here, the alkoxy group, phenoxy group, alkylphenoxy group, and acyloxy group may have an oxygen-containing substituent.) n is an integer of 3 to 1.