JPH10147665A - Polyvinyl alcohol-starch modified product composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition capable of being dissolved (gelatinized) at low temperature, stable in an aqueous solution state for a long period, excellent in compatibility, and capable of being used as a sizing agent for fibers by subjecting polyvinyl alcohol and starch to the Michael addition reaction using a vinyl compound. SOLUTION: This composition comprises (A) a modified PVA obtained by subjecting (i) PVA to a Michael addition reaction of (ii) a vinyl compound (preferably acrylamide) and (B) a modified starch obtained by subjecting (iii) starch to the Michael addition reaction of the component (ii). The composition is obtained by adding the component (ii) to the mixture of the components (i) and (iii) and subsequently subjecting the mixture to the Michael addition reaction. The molar ratio of the component (i) to the component (iii) is 1:99 to 99:1, preferably 10:90 to 90:10 in the reaction. The component (ii) is preferably used in an amount of 1-150mol.% based on the mixture of the component (i) with the component (iii).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified polyvinyl alcohol-starch composition which can be dissolved at a low temperature and has good compatibility, a method for producing the same, and a fiber sizing agent containing this composition.

[0002]

2. Description of the Related Art A polyvinyl alcohol (hereinafter abbreviated as PVA) resin has characteristics such as good stability of an aqueous solution and an extremely high strength of a film obtained as compared with other water-soluble substances. Therefore, they are widely used as fiber sizing agents such as warp sizing agents and glass fiber sizing agents, paper processing agents, adhesives and the like.

[0003] When PVA is used, it is widely used to blend it with starch for the purpose of reducing the total cost of the composition, but there are many problems. For example, in applications as warp sizing agents, the strength of the resulting film is significantly reduced depending on the type of starch to be blended, causing troubles in weaving, or storing the warp sizing aqueous solution without stirring or under weak stirring. Otherwise, the aqueous solution may be separated into a phase mainly composed of starch and a phase mainly composed of PVA, and a problem may occur that stable gluing cannot be performed. Also, the glass fiber sizing agent has a problem in that the film properties are insufficient due to poor compatibility and fuzzing occurs. Furthermore, in order to adjust the glue,
The starch is heated to a high temperature (120 to 130) using a high pressure cooker or the like.
C), which significantly deteriorates the working environment.

On the other hand, attempts have been made to blend a PVA-based resin and starch to produce a film in which only the starch is used to improve the fragility of the film. Poor properties, there are various problems in handling, such as phase separation between the two, the viscosity of the aqueous solution changes with time, and also, with respect to the mechanical properties of the resulting film, satisfactory ones have not been obtained. Was.

In order to solve the above problem, Japanese Patent Laid-Open Publication No.
Japanese Patent No. 3259 proposes a composition comprising PVA and a modified starch obtained by graft-polymerizing a monomer onto a starch. However, these compositions may be modified only with starch and have satisfactory compatibility. Not to give.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above, and has a lower dissolution (gelatinization) temperature and better compatibility than conventional PVA / starch based pastes.
It is an object of the present invention to provide a modified PVA-starch composition which provides excellent film properties and sizing properties when used as a warp paste for cotton or a sizing agent for glass fibers. Another object of the present invention is to provide a production method for efficiently producing such a modified PVA-starch composition.

[0007]

Means for Solving the Problems The present inventors have made intensive studies in view of the above circumstances, and as a result, it has been found that a modified composition obtained by adding a vinyl compound to PVA and starch with Michael is far more than the same type of starch. It dissolves (gelatinizes) at a low temperature, and the aqueous solution of the modified composition is stable and excellent in compatibility even when left for a long time. For example, when used as a fiber sizing agent, it has excellent film properties and bunching properties. Have been found, leading to the present invention.

That is, the modified PVA-starch composition of claim 1 is a modified PVA obtained by subjecting PVA to a Michael addition reaction with a vinyl compound in order to solve the above problems.
And a modified starch obtained by subjecting a vinyl compound to a starch by a Michael addition reaction.

The composition according to claim 2 is a composition according to claim 1,
In the VA-modified starch composition, the vinyl compound is acrylamide.

[0010] The production method according to claim 3 is a method for producing the modified PVA-starch composition according to claim 1 or 2, wherein a vinyl compound is added to a mixture of PVA and starch, and a Michael addition reaction is carried out. It is characterized by performing.

[0011] The production method according to claim 4 is a method for producing the modified PVA-starch composition according to claim 1 or 2, wherein a Michael addition reaction is carried out by mixing polyvinyl alcohol or starch with a vinyl compound. Then, polyvinyl alcohol and starch not used in the reaction are added to the reaction system, and a vinyl compound present in the reaction system is subjected to a Michael addition reaction with polyvinyl alcohol or starch added thereafter. And

[0012] The modified PVA-starch composition of claim 5 comprises:
It comprises a modified PVA obtained by subjecting PVA to a Michael addition reaction with a vinyl compound and then hydrolyzing, and a modified starch obtained by subjecting the vinyl compound to a Michael addition reaction with starch and then hydrolyzing.

The composition according to claim 6 is a composition according to claim 5,
In the VA-modified starch composition, the vinyl compound is acrylamide.

According to a seventh aspect of the present invention, there is provided a method for producing the modified PVA-starch composition according to the fifth or sixth aspect, wherein a vinyl compound is added to a mixture of PVA and starch, and a Michael addition reaction is carried out. It is characterized by hydrolyzing after performing.

An eighth aspect of the present invention is the method for producing the modified PVA-starch composition according to the fifth or sixth aspect, wherein a polyvinyl alcohol or starch is mixed with a vinyl compound to carry out a Michael addition reaction. Then, polyvinyl alcohol and starch not used in the above-mentioned reaction are added to the reaction system, and the vinyl compound present in the reaction system is subjected to a Michael addition reaction with the polyvinyl alcohol or starch added thereafter, and then hydrolyzed. It is characterized by decomposing.

The sizing agent for fibers according to the ninth aspect is characterized in that
5. A modified PVA-starch composition according to any one of items 5 and 6.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The degree of saponification of PVA used in the present invention is not particularly limited, but when a strong alkali is used as a catalyst, the saponification degree is preferably 80 mol% or more, more preferably 95 mol% or more. This is to prevent the alkali of the catalyst from being consumed by saponification and to suppress the amount of by-products (acetate) generated by saponification.

The degree of polymerization of PVA is preferably from 50 to 8,000, and more preferably from 300 to 4,000 from the viewpoint of availability.

In addition to the above PVA, an ethylene-vinyl alcohol copolymer or a modified PVA such as carboxy-modified, sulfone-modified, cation-modified, or silyl-modified can also be used as a raw material. In this case, the modification rate of the modified PVA used as a raw material is not particularly limited, but is usually about 0.5 to 10 mol%.

These PVAs may be used in combination of two or more as necessary.

On the other hand, the starch used in the present invention includes:
Raw starch such as corn starch, potato starch, wheat starch, tapioca starch, rice starch, sweet potato starch, α starch, oxidized starch, dextrin, cationized starch, cross-linked starch, grafted starch, esterified starch (starch acetate, phosphoric acid Modified starches such as starch, starch sulfate, starch nitrate, starch xanthate, starch acetoacetate), etherified starch (carboxymethylated starch, methylated starch, hydroxyethylated starch, hydroxypropylated starch) and the like. As a matter of course, two or more of these starches may be used in combination.

The vinyl compound used in the present invention includes acrylonitrile, acrylamide, N-methylolacrylamide, N, N-dimethylacrylamide,
Nonionic, such as acrylic acid or a salt thereof, acrylate, 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof, vinylsulfonic acid or a salt thereof, vinylsulfoxide, vinylsulfone, maleic acid, and maleic diester; N, N-dimethylaminoethyl acrylate or a quaternary salt thereof, N, N-dimethylaminopropylacrylamide or a quaternary salt thereof, N-vinylformamide, N-vinyl
And cationic vinyl compounds such as vinylacetamide. Moreover, these can also be used in combination of 2 or more types.

The composition of the present invention is characterized in that it contains a product obtained by subjecting PVA and starch to a Michael addition modification with the above-mentioned vinyl compound. However, other reactive agents may be used as long as the performance is not impaired. You may use together. Examples of these reactive agents include aldehydes, epoxies, urea resins, melanin resins, glyoxals, isocyanates, monochloroacetic acid, epichlorohydrin and the like.

The modified composition of the present invention can be obtained by a method in which PVA and starch are separately Michael-modified and then mixed at a predetermined ratio, a method in which PVA and starch are mixed and then Michael addition-modified. There is.

In general, the reactivity of Michael addition of vinyl compounds is higher in PVA than in starch. Therefore, when PVA and starch are separately modified, there may be a problem that a large amount of unreacted vinyl compound remains in the production of the modified starch. Such a problem can be solved.

If PVA and starch are blended in a predetermined ratio in advance and a vinyl compound is added, a modified composition corresponding to the blending ratio and the reactivity of each is obtained. If it is desired to control the denaturation rates of PVA and starch, one of the Michael addition reactions is performed in advance, and in the middle of the reaction, or in extreme cases, when the reaction reaches equilibrium, the remaining one is added to the reaction system. And a Michael addition reaction may be further performed. These all belong to the scope of the manufacturing method of the present invention.

Next, a production method in which the above PVA and starch are mixed and both of them are simultaneously Michael-modified is described.

This production method comprises a homogeneous reaction in which PVA, starch, and a vinyl compound are dissolved in water or the like and reacted,
The reaction is roughly classified into a heterogeneous reaction in which a reaction is carried out in a system in which a small amount of water does not dissolve the starch or a solvent in which both PVA and starch are insoluble is added and the reaction is carried out in a suspension or slurry system. Industrially, a heterogeneous reaction having a high reaction rate is advantageous.

The mixing ratio (molar ratio) of PVA and starch used in the above reaction is in the range of PVA: starch = 1: 99 to 99: 1, preferably 10:90 to 90:10.

The amount of the vinyl compound used in the above reaction is preferably 1 to 15 parts with respect to the PVA / starch mixture.
0 mol%, more preferably 3 to 100 mol%.

In order to allow the above reaction to proceed smoothly, it is preferable to use a basic catalyst. Examples of the type of the basic catalyst include caustic soda, caustic potash, sodium methoxide, and triethylamine. Of these, caustic soda and caustic potash are particularly preferable.

The amount of the basic catalyst to be added is preferably 0.5 to 100 mol%, more preferably 2 to 50 mol%, based on the PVA / starch mixture.

The reaction time of the Michael addition reaction is usually 30 minutes to 10 hours, and the reaction temperature is in the range of 5 to 90 ° C, preferably 20 to 70 ° C. Depending on the type of the vinyl compound (for example, acrylonitrile, acrylamide, etc.), it is also possible to carry out hydrolysis by adding an alkali or the like thereafter. In this case, it may be partially or completely hydrolyzed depending on the use. The hydrolyzate also belongs to the range of the modified PVA-starch modified composition of the present invention.

In the hydrolysis, alkali agents such as caustic soda, caustic potash, lithium hydroxide and sodium carbonate, as well as alkylamines such as dimethylamine and alkanolamines such as monoethanolamine can be used.

Further, by carrying out the reaction in a nitrogen atmosphere, it is possible to prevent coloring of the product and breaking of the molecular chain by radicals.

The production method in which the addition of either one of PVA and starch is performed first and the other is added later is different from the above production method except that the timing of mixing the PVA and starch is different. There is no.

The modified PVA-starch composition of the present invention comprises:
Other PVA, starch, C, and so forth as long as the effects of the invention are not impaired.
MC, inorganic pigments, organic pigments, other auxiliaries (antifoaming agents, antifungal agents, preservatives, antioxidants, antistatic agents, plasticizers) and the like can be appropriately used.

The modified PVA-starch composition of the present invention has a low dissolution (gelatinization) temperature, good compatibility, and provides a tough and flexible film or film. It is extremely useful in applications where PVA and starch are used, such as an agent. For example, when used as a sizing agent for fibers, mixing of PVA and starch conventionally performed,
The operations such as glue firing and agitation for preventing separation of the size liquid can be omitted or significantly simplified. In addition,
The grades of PVA and starch used in the present invention, the type of vinyl compound, and the like may be appropriately selected according to the use of the modified PVA-starch composition.

The reason why the modified PVA-starch composition of the present invention can be dissolved at a low temperature is that the vinyl compound undergoes a Michael addition reaction to the hydroxyl group of the PVA and the starch, whereby the strong crystalline portion is destroyed and, as a result, the hydrophilicity is reduced. Is considered to be increased.

The first reason why the compatibility is improved is that structural affinity is improved by introducing the same type of functional group into both PVA and starch. Therefore,
Michael addition-modified P of different vinyl compounds
There is no particular problem even if VA and starch are used as long as the compatibility is good, but from the above viewpoint, it is preferable to use the same type of vinyl compound for PVA and starch.

[0041]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention thereto. Unless otherwise specified, "%"
It means "% by weight".

Example 1 Powdered PVA (polymerization degree: 1,750, saponification degree: 98.8 mol%) was placed in a 5-liter horizontal blender under a nitrogen atmosphere.
300 g and 200 g of corn starch are added, and while stirring, 3 g
130 g of 0% -caustic soda aqueous solution was added dropwise.
For 1 hour. Next, 426 g of a 50% aqueous solution of acrylamide and 5 g of polyethylene glycol (molecular weight: 300) were added dropwise, and a Michael addition reaction was performed at 40 ° C. for 6 hours. The obtained product was purified with methanol and then dried to obtain a white modified composition.

Example 2 After performing a Michael addition reaction at 40 ° C. for 6 hours in the same manner as in Example 1, a further 170 g of 48% caustic soda was added, the temperature was raised to 80 ° C., and hydrolysis was performed for 3 hours. Was. The obtained product was purified with methanol and then dried to obtain a white modified composition.

Example 3 Powdered PVA (degree of polymerization: 550, degree of saponification: 88.8 mol%) was placed in a 5-liter horizontal blender under a nitrogen atmosphere.
0 g, oxidized starch 400 g, isopropyl alcohol 80
0 g was added, and 30% aqueous sodium hydroxide solution 100 was added under stirring.
g was added dropwise and alcoholation was performed at 40 ° C. for 1 hour. Subsequently, 220 g of a 50% aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate was added dropwise, and a Michael addition reaction was performed in a slurry system at 60 ° C. for 9 hours. The obtained product was filtered and then dried to obtain a white modified composition.

Example 4 Powdered PVA (degree of polymerization: 550, degree of saponification: 96.8 mol%) 40 in a 5-liter horizontal blender under a nitrogen atmosphere.
0 g was added thereto, and a 30% aqueous sodium hydroxide solution 120 was added with stirring.
g was added dropwise and alcoholation was performed at 40 ° C. for 1 hour. Next, 159 g of acrylonitrile was added dropwise,
After performing the Michael addition reaction at 30 ° C. for 2 hours, 100 g of hydroxypropylated starch was added, and the Michael addition reaction was continued at the same temperature for 2 hours. Next, 170 g of 48% -caustic soda was added, the temperature was raised to 80 ° C., and hydrolysis was performed for 3 hours. The obtained product was purified with methanol and then dried to obtain a white modified composition.

Example 5 Powdered PVA (degree of polymerization: 2,550, degree of saponification: 95.7 mol%) was placed in a 5-liter horizontal blender under a nitrogen atmosphere.
400 g was added, and a 30% aqueous sodium hydroxide solution 7 was added under stirring.
0 g was added dropwise, and alcoholation was performed at 30 ° C. for 1 hour. Next, 390 g of a 50% -acrylamide aqueous solution
Was added dropwise, and a Michael addition reaction was performed at 50 ° C. for 4 hours. The product obtained is purified with methanol and then dried,
A white powder was obtained.

On the other hand, 500 g of potato starch was added with stirring.
170 g of a 30% aqueous solution of sodium hydroxide was added dropwise,
The alcoholation was carried out at 1 ° C. for 1 hour. Then, 50%-
490 g of an aqueous acrylamide solution was added dropwise, and a Michael addition reaction was performed at 70 ° C. for 8 hours. The obtained product was purified with methanol and then dried to obtain a white powder.

The PVA-modified product and the starch-modified product thus obtained were mixed in a weight ratio of PVA-modified / starch-modified = 7 /
3 to obtain a modified composition.

Example 6 400 g of corn starch was added to a 5 liter horizontal blender under a nitrogen atmosphere, and 130 g of a 30% aqueous solution of sodium hydroxide was added dropwise with stirring, followed by alcoholation at 40 ° C. for 1 hour. Then, 445 g of a 50% -acrylamide aqueous solution, polyethylene glycol (molecular weight: 30)
0) 5 g was added dropwise, and a Michael addition reaction was performed at 50 ° C. for 2 hours. Subsequently, powder PVA (degree of polymerization 1,750,
100g of saponification degree 98.8 mol%)
For 2 hours to continue the Michael addition reaction. The obtained product was purified with methanol and then dried to obtain a white modified composition.

Comparative Examples 1 to 3 Unmodified PVA and starch were blended in the following proportions.
An A / starch mixture was prepared.

[0051]

[Table 1] .

Physical property tests Physical properties tests of the compositions prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were performed as follows.

1. Compatibility test A 5% solids aqueous solution was dissolved at a dissolution temperature of 70 ° C. and 120 ° C., respectively, and the state of separation was observed. The results are shown in [Table 2].

[0054]

[Table 2] .

2. An aqueous solution having a solid content of 5% was prepared at 120 ° C., and a film having a thickness of about 200 μm was obtained by a casting method. About this, Shimadzu Autograph A under the condition of 25 ° C and RH65%
The film properties were measured with G-100A. The results are shown in [Table 3].

[0056]

[Table 3] .

Performance test of warp sizing Using the compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 3, a paste solution was prepared as follows, and a performance test of warp sizing of 40 ^s cotton was performed. . Table 4 shows the size adjustment temperature, the size of the glue (weight% based on the weight of the warp), and the test results.

(Preparation of size liquid) Size 8.0% (compositions obtained in Examples and Comparative Examples) Oil 0.8% (Maconol TS-253, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) Measurement of force: TM-type embracing force tester (load: 500 g) Measurement of fluffiness: Ever photoelectric tube type fluff measuring device (1 mm
The above is counted.) Measurement of strong elongation ... Shimadzu Autograph AG-100A (2
(5 ° C., RH 65%) Measurement of smoothness: traveling type smoothness tester Divideability: The film used for the measurement of the film properties was 3
It was cut into cm squares and cut by hand. The torn state at this time was visually evaluated.

[0059]

[Table 4] .

Performance test of glass fiber sizing agent The performance test of the glass fiber sizing agent was performed on the compositions obtained in Examples 1, 4, 5 and Comparative Examples 1 to 3 as follows.

(Composition) Compositions obtained in Examples and Comparative Examples 5.0% Paraffin wax (melting point 55 ° C.) 1.5% Sorbitan monostearate 0.2% Tetraethylenepentamine / stearic acid condensation 0.3% Hydrogenated castor oil 0.3% Formalin 0.1% The sizing agent prepared with the above composition is supplied to a roll-type applicator, and 400 glass filaments (8-micron diameter) are applied from a molding bushing. And applied. The physical properties of the yarn obtained by converging this material, winding it up, and then rewinding it are shown in [Table 5].

1. Solution stability The sizing solution was allowed to stand for one day, and the state of separation was observed.

2. Migration index This is a value obtained by dividing the maximum adhesion rate of the yarn by the minimum adhesion rate. The smaller the value, the smaller the migration.

3. Fuzz suppression The amount of fuzz generated per hour was expressed in mg / hr.

4. Deoiling property The powder was calcined at 350 ° C. for 4 hours to remove oil, and the thermal decomposition property of the appearance was determined.

O Almost completely deoiled.

(6) Some carbides remain.

X A large amount of unoiled material remains.

[0069]

[Table 5] .

[0070]

The modified PVA-starch compositions of the first, second, fifth and sixth aspects have a low dissolution (gelatinization) temperature, good compatibility, and provide a tough and flexible film. Therefore, it is very suitably used for applications where PVA and starch are used, such as cotton warp sizing and glass fiber sizing agents.

According to the production method of claims 3, 4, 7, and 8, the above-mentioned modified PVA-starch composition can be easily obtained, and the problem that unreacted vinyl compound remains can be solved.

Further, the sizing agent for fibers according to the ninth aspect has excellent performance and, in the production process thereof, has conventionally required mixing of PVA and starch, firing of glue, stirring to prevent separation of the size liquid, and the like. Work can be simplified, and costs can be reduced.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 129/04 C09J 129/04 B

Claims (9)

[Claims] 1. A modified polyvinyl alcohol-starch composition comprising a modified polyvinyl alcohol obtained by subjecting a vinyl compound to a Michael addition reaction with polyvinyl alcohol and a modified starch obtained by subjecting a vinyl compound to a Michael addition reaction to starch. Stuff. 2. The modified polyvinyl alcohol-starch composition according to claim 1, wherein the vinyl compound is acrylamide. 3. The process for producing a modified polyvinyl alcohol-starch composition according to claim 1, wherein a vinyl compound is added to a mixture of polyvinyl alcohol and starch and a Michael addition reaction is carried out. 4. A Michael addition reaction is carried out by mixing polyvinyl alcohol or starch with a vinyl compound, and polyvinyl alcohol and starch not used in the above reaction are added to the reaction system. 2. A Michael addition reaction of an alcohol or starch with a vinyl compound present in the reaction system.
Or the method for producing the modified polyvinyl alcohol-starch composition according to 2. 5. A modified polyvinyl alcohol obtained by subjecting a vinyl compound to a Michael addition reaction to polyvinyl alcohol followed by hydrolysis, and a modified starch obtained by subjecting a vinyl compound to a starch addition reaction and hydrolyzing the starch. Modified polyvinyl alcohol-starch composition. 6. The modified polyvinyl alcohol-starch composition according to claim 5, wherein the vinyl compound is acrylamide. 7. The modified polyvinyl alcohol-starch composition according to claim 5, wherein a vinyl compound is added to a mixture of polyvinyl alcohol and starch, and the mixture is subjected to a Michael addition reaction and then hydrolyzed. Manufacturing method. 8. A Michael addition reaction is carried out by mixing polyvinyl alcohol or starch with a vinyl compound, and polyvinyl alcohol and starch not used in said reaction are added to the reaction system. The method for producing a modified polyvinyl alcohol-starch composition according to claim 5 or 6, wherein the alcohol or starch is subjected to a Michael addition reaction with a vinyl compound present in the reaction system, followed by hydrolysis. 9. A sizing agent for fibers comprising the modified polyvinyl alcohol-starch composition according to any one of claims 1, 2, 5, and 6.