JPH1067827A - Polyvinyl acetate emulsion and textile size having antiredeposition effect - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyvinyl acetate emulsion which has a long-term viscosity stability, good low-temperature film-forming properties even when not plasticized, forms a coating film having a high hardness and an excellent heat resistance, and prevents soil redeposition when used as a textile size. SOLUTION: This emulsion is obtained by emulsion-copolymerizing 100 pts.wt. mixture comprising 99.5-90wt.%, based on the entire mixture, vinyl acetate and 0.5-10wt.% carboxylic monomer in the presence of 30-200 pts.wt. modified starch mixture comprising 10-90wt.%, based on the entire modified starch mixture, modified starch having a viscosity of 1-1,000cP as measured in the 10% aqueous solution thereof at 50 deg.C and 10-90wt.% saccharified starch having a viscosity of 3-300cP as measured in the 50% aqueous solution thereof at 50 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms a film having good low-temperature film-forming properties, low-temperature fluidity and viscosity stability over time, and has high hardness and excellent heat resistance. The present invention relates to a polyvinyl acetate emulsion that hardly accumulates.

[0002]

2. Description of the Related Art Conventionally, polyvinyl acetate emulsions are mainly composed of polyvinyl alcohol (hereinafter abbreviated as PVA).
Is used as a protective colloid agent for emulsion polymerization. The use of PVA makes it easy to produce an emulsion, the viscosity can be arbitrarily adjusted, and the adhesive performance is relatively excellent. However, the viscosity of the emulsion at a low temperature is high, and the emulsion must be heated in some cases. To give fluidity. Further, the polyvinyl acetate emulsion of the protective colloid of PVA must be added with a considerable amount of a plasticizer in order to improve the low-temperature film-forming property, and the addition of the plasticizer significantly softens the film and reduces the heat resistance. It decreases significantly.

[0003] On the other hand, it has been known for a long time that starch derivatives are used as protective colloids. For example, US Pat.
No. 322 discloses that stable use is made of a combination of 0.1 to 6% by weight of hydroxyethyl or hydroxypropylated starch based on a monomer and an emulsifier of 0.8 to 2.3% by weight based on a monomer. There is disclosed a method for emulsion polymerizing a polymer emulsion. This is less than 6% by weight of the starch derivative per monomer.

Japanese Patent Application Laid-Open No. Sho 62-161848 discloses a method in which an alkyl or alkenyl succinic esterified starch is used as a protective colloid in an amount of 1 to 10% by weight based on all monomers. It is an object not to use an emulsifier and to improve the miscibility with borax as compared with a case where is used as a protective colloid.

Further, JP-A-6-93007 discloses a polymer emulsion comprising 50 to 100% by weight of vinyl acetate and 0 to 50% by weight of at least one copolymerizable monomer. A polyvinyl acetate emulsion is disclosed, wherein the polymer emulsion is produced by emulsion polymerization using a water-soluble modified starch of 10 to 200% by weight of all monomers as a protective colloid. However, there is a problem that when the ratio of starch used is so high, the viscosity stability over time of the emulsion becomes worse, and even after one month, even the emulsion having relatively good viscosity stability becomes twice the initial viscosity.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to form a film having good viscosity stability over time, good low-temperature film-forming properties without adding a plasticizer, and excellent hardness and heat resistance. An object of the present invention is to provide a polyvinyl acetate emulsion in which dirt hardly accumulates when used as a fiber sizing agent.

[0007] In order to achieve the above object, those obtained by emulsifying starch at a high content provide a low-temperature film-forming property without adding a plasticizer, and form a film having high hardness and excellent heat resistance. . However, even if the low-temperature fluidity is good immediately after production, the viscosity stability over time of the emulsion becomes worse when the usage ratio of starch becomes higher, and even after one month, even the relatively stable viscosity becomes twice the initial viscosity. There is a problem that.

Further, when the polyvinyl acetate emulsion is used as a fiber sizing agent, if washing and sizing are repeated, dirt gradually accumulates together with the polyvinyl acetate emulsion, and the texture of the fiber also changes.

[0009]

According to the present invention, 99.5% to 90% by weight of vinyl acetate based on the total monomers is used, and 0.5% by weight of vinyl acetate.
10 to 10% by weight of the total monomer composed of the carboxyl group-containing monomer and 10 to 10 parts by weight of the total modified starch
90% by weight, 50 ° C, 10% aqueous solution, 1-1000CP
Emulsion copolymerization is carried out using 30 to 200 parts by weight of a total modified starch composed of 10 to 90% by weight of a starch saccharified product having a viscosity of 3 to 300 CPS in a 50% aqueous solution at 50 ° C. and 50% aqueous solution in the same manner as a modified starch having a viscosity of S. The resulting polyvinyl acetate emulsion has good low-temperature film-forming properties, low-temperature fluidity, and good viscosity stability over time, and forms a film with high hardness and excellent heat resistance. It has been found that when used as an agent, good tensile hardness can be obtained, and dirt hardly accumulates.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The monomers used in the polymerization of the polyvinyl acetate emulsion of the present invention include, in addition to vinyl acetate, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid and itaconic acid. Is mentioned. In addition, various monomers such as acrylic acid ester, methacrylic acid ester, ethylene, vinyl chloride, styrene and the like can also be mentioned as copolymerizable monomers.

The modified starch used in the emulsion polymerization of the present invention includes raw starches such as potato starch, sweet potato starch, tapioca starch, sago starch, wheat starch, corn starch, rice corn starch, rice starch, and the like. Oxidation and hydrolysis by an oxidizing agent, hydrolysis by an enzyme, and the like can be used to reduce the molecular weight (decrease the viscosity). The degree of lowering the molecular weight (lowering the viscosity) can be determined as appropriate, but the viscosity is 50 ° C. and a 10% aqueous solution is 1 to 1000 CPS.
With a viscosity of 50 ° C, 50% aqueous solution at 3-300C
PS is used in combination to obtain viscosity stability. These low molecular weight modified starches are etherified or acetic esterified such as hydroxyethylated, hydroxypropylated, carboxymethylated, tertiary cationized, quaternary cationized, and phosphoric acid ester in order to increase the viscosity stability over time. Conversion, urea phosphate esterification, succinate esterification,
If necessary, esterification such as octenyl succinate esterification, maleate esterification, and phthalate esterification can be performed by appropriately selecting the type of chemical conversion and the degree of chemical conversion (degree of substitution).

Examples of these low molecular weight modified starches include:
Potato starch, tapioca starch, corn starch, corn starch, hydroxyethylation, hydroxypropylation, tertiary cationization, quaternary cationization or other etherification or acetate esterification, phosphate esterification, urea phosphate ester , Succinic esterification, octenyl succinic esterification, maleic esterification, phthalic acid esterification and the like are preferably subjected to acid-, oxidizing-agent, or enzymatic reduction to a low molecular weight (low viscosity). Used. Viscosity is 50 ℃, 10% aqueous solution is 1
Those having a viscosity of 50 C and a 50% aqueous solution having a viscosity of 3 to 300 CPS can be adjusted by controlling the degree of molecular weight reduction. Further, as a starch saccharified product having a viscosity of 30 ° C. and a 50% aqueous solution of 3 to 300 CPS, a starch saccharified product such as sorbitol, reduced maltose, reduced starch syrup, or the like can be exemplified.

The polymerization initiator is not limited as long as it can initiate radical polymerization in an aqueous system, and the polymerization can be carried out by a conventional method. Typically, water-soluble peroxides or salts thereof, such as hydrogen peroxide, peracetic acid, persulfate or their ammonium and alkali metal salts, such as ammonium persulfate, sodium peracetate, lithium persulfate, persulfate Potassium and sodium persulfate. Alternatively, organic peroxides such as benzoyl peroxide, t-butyl hydroperoxide, 2,2'-azobisisobutyronitrile, etc. can be used. A suitable concentration of the initiator is about 0.05-5.0% by weight, preferably about 0.1-3.0% by weight, based on the weight of the polymer. The free radical initiator can be utilized alone to thermally decompose to release the free radical initiating species, and can also be used as a redox system in combination with a suitable reducing agent. Specific examples of the reducing agent include sodium metasulfite, potassium metasulfite, sodium pyrosulfite, sodium formaldehyde sulfoxide and the like. The reducing agent is generally used in an amount ranging from about 0.1 to 3% by weight based on the weight of the polymer.

The emulsion concentration can be appropriately changed depending on the application within the range of 20 to 70% by weight depending on the viscosity and the coating method. Further, additives can be added as needed during or after the polymerization.

[0015] The optional additives used include:
Commonly used plasticizers, surfactants, antifoaming agents, preservatives, fillers such as calcium carbonate, talc, clay and other inorganic substances and wheat flour, starch and wood flour and other organic substances. If you need to delay
And an aqueous solution of a starch derivative, glycerin and the like.

The following examples further illustrate the invention but do not limit it. In the examples, unless otherwise noted, all parts are by weight and all temperatures are in degrees Celsius.

【Example】

Example 1 Tapioca starch was subjected to hydroxypropylation (substitution degree: MS = 0.06) and was made low molecular weight by an oxidizing agent (viscosity: 50 ° C., 25% CPS with 10% aqueous solution).
Parts and 70% sorbite aqueous solution (viscosity 50 ° C, 50%
50 parts by weight of 5 CPS) in 250 parts of water,
The mixture was heated to 90 ° C. and dissolved by stirring. Next, 93.6 parts of a vinyl acetate monomer and 8 parts of an 80% aqueous acrylic acid solution were added to 0.7 part of ammonium persulfate as an initiator in a conventional manner.
Emulsion polymerization was carried out by dropping over a period of time, and the pH was adjusted to 4.
5. A polyvinyl acetate emulsion was obtained by adjusting the emulsion solid content to 40% (Sample No. 1).

Example 2 Acetylation was performed using corn starch as a raw material (substitution degree D.
S. = 0.08), and reduced in molecular weight (viscosity is 5
Hydroxypropylated (substitution degree MS = 0.06) enzymatically modified dextrin (having a viscosity of 50 ° C. and a 50% aqueous solution of 120 CPS) using 60 parts of 0 ° C., 10% aqueous solution at 12 CPS and corn starch as raw materials. ) 40
Was dispersed in 250 parts of water and dissolved by heating to 90 ° C. while stirring. Next, 96 parts of a vinyl acetate monomer and 4 parts of crotonic acid were added dropwise over a period of 3 hours using 0.7 parts of ammonium persulfate as an initiator and emulsion polymerization was carried out.
H was adjusted to 4.5 and the solid content of the emulsion was adjusted to 40% to obtain a polyvinyl acetate emulsion (Sample No. 2).

Example 3 Acetylation using tapioca starch as a raw material (substitution degree DS
= 0.07), and reduced in molecular weight by an oxidizing agent (viscosity of 50
120 parts of a 10% aqueous solution at 15 ° C.) and 90 parts of a 70% aqueous solution of reduced starch syrup (viscosity is 50 ° C., 90 CPS at 50% aqueous solution) are dispersed in 340 parts of water.
The mixture was heated and stirred until dissolved. Next, vinyl acetate monomer 9 was prepared in a conventional manner using 0.7 parts of ammonium persulfate as an initiator.
Emulsion polymerization was carried out by dropping 3.6 parts and 8 parts of 80% acrylic acid aqueous solution in 3 hours, and after the polymerization was completed, the pH was adjusted to 4.5 and the solid content of the emulsion was adjusted to 40% to obtain a polyvinyl acetate emulsion. (Sample No. 3).

Example 4 Potato starch was subjected to carboxymethylation (substitution degree DS = 0.05) using a raw material, and the molecular weight was reduced by an oxidizing agent (viscosity is 50 ° C., 670 CPS in 10% aqueous solution) 33
Part and corn starch as raw material for enzyme-modified dextrin (viscosity 50 ° C, 50% aqueous solution at 100 CPS)
18 parts were dispersed in 200 parts of water and dissolved by heating to 90 ° C. while stirring. Next, 96 parts of a vinyl acetate monomer and 4 parts of crotonic acid were added dropwise over a period of 3 hours using 0.7 parts of ammonium persulfate as an initiator and emulsion polymerization was carried out. The content was adjusted to 40% to obtain a polyvinyl acetate emulsion (Sample No. 4).

Comparative Example 1 Tapioca starch was subjected to hydroxypropylation (substitution degree MS = 0.06) using a raw material, and the molecular weight was reduced by an oxidizing agent (viscosity was 50 ° C., 25% CPS in a 10% aqueous solution).
0 parts were dispersed in 280 parts of water and dissolved by heating to 90 ° C. while stirring. Then, 93.6 parts of vinyl acetate monomer and 83.6 parts of 8
Emulsion polymerization was carried out by dropping 8 parts of 0% acrylic acid aqueous solution over 3 hours, and after the polymerization was completed, the pH was adjusted to 4.5 and the emulsion solid content was adjusted to 40% to obtain a polyvinyl acetate emulsion (Sample No. 5). ).

Comparative Example 2 Acetylation using tapioca starch as a raw material (substitution degree DS
= 0.07), and reduced in molecular weight by an oxidizing agent (viscosity of 50
180 parts of a 10% aqueous solution (CPS, 15 CPS) was dispersed in 400 parts of water and dissolved by heating to 90 ° C. with stirring. Next, 93.6 parts of a vinyl acetate monomer and 8 parts of an 80% aqueous solution of acrylic acid were added dropwise over a period of 3 hours using 0.7 part of ammonium persulfate as an initiator and emulsion polymerization was carried out. And adjusting the emulsion solid content to 40% to obtain a polyvinyl acetate emulsion (Sample No. 6).

Comparative Example 3 Potato starch was subjected to carboxymethylation (substitution degree DS = 0.05) with a low molecular weight (viscosity of 50 ° C., 670 CPS in 10% aqueous solution) using an oxidizing agent 51
Parts were dispersed in 200 parts of water and dissolved by heating to 90 ° C. while stirring. Next, 96 parts of a vinyl acetate monomer and 4 parts of crotonic acid were added dropwise over a period of 3 hours using 0.7 parts of ammonium persulfate as an initiator and emulsion polymerization was carried out.
H was adjusted to 4.5 and the solid content of the emulsion was adjusted to 40% to obtain a polyvinyl acetate emulsion (Sample No. 7).

Example 3 The viscosities of the emulsions of Sample Nos. 1, 2, 3, 4, 5, 6, and 7 obtained in Examples 1, 2, 3, 4 and Comparative Examples 1, 2, and 3 immediately after production and 40, respectively. After the passage of days, the viscosity was measured.
The results are shown in Table 1 (viscosity at 30 ° C., unit CPS).

[Table 1] Next, the hardness of the film obtained by drying the emulsions of Sample Nos. 1, 2, 3, 4, 5, 6, 7 and a commercially available vinyl acetate emulsion to which no starch was added (Sample No. 8) at room temperature ( Durometer D hardness) according to JIS K7215
It was measured according to "durometer hardness of plastic". The results are shown in Table 2 (hardness of film, unit durometer D).

[Table 2] Next, the emulsions of Sample Nos. 1, 2, 3, 4, 5, 6, 7, and 8 were each diluted to 5%, a cotton cloth (gold width) was glued, ironed, and washed in a series of 5 times. Repeat the bending resistance of the cloth (JIS L1096 "Bending resistance (45
° cantilever method) and the adhesion rate (accumulation property) of the glue (emulsion) were measured. Table 3 shows the results.
(Unit: mm) and Table 4 (adhesion rate, unit%).

[Table 3]

[Table 4] Further, the degree of softening at the time of heating using the cloth after one time of gluing and the cloth after final desizing was used as an index of heat resistance by checking the slipperiness at the time of ironing. The results are shown in Table 5 (iron slipperiness,
◎: very slippery, ○: slippery, Δ: slightly slippery, ×: very slippery).

[Table 5]

[0024]

The polyvinyl acetate emulsion of the present invention has good low-temperature film forming properties, low-temperature fluidity and viscosity stability over time,
It forms a film having high hardness and excellent heat resistance, and is excellent in that dirt hardly accumulates when used as a fiber sizing agent. This is considered to be due to the combination use of two types of modified viscosity starch, in particular, the modified viscosity starch with lower viscosity stabilizes the viscosity over time and enhances the desizing property when used as a fiber sizing agent.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location D06M 15/333 D06M 15/333

Claims (2)

[Claims] (1) 100 parts by weight of a total monomer composed of 99.5 to 90% by weight of vinyl acetate and 0.5 to 10% by weight of a carboxyl group-containing monomer based on the total amount of monomers. ,
90 to 10% by weight of the total modified starch at 50 ° C., 10%
Same as the modified starch having a viscosity of 1 to 1000 CPS in an aqueous solution.
A polyvinyl acetate emulsion obtained by emulsion-copolymerizing 30 to 200 parts by weight of a total modified starch consisting of a starch saccharified product having a viscosity of 300 CPS. 2. 100 parts by weight of a total monomer comprising 99.5 to 90% by weight of vinyl acetate and 0.5 to 10% by weight of a carboxyl group-containing monomer based on the whole monomer. ,
90 to 10% by weight of the total modified starch at 50 ° C., 10%
Same as the modified starch having a viscosity of 1 to 1000 CPS in an aqueous solution.
A non-accumulative fiber paste mainly comprising a polyvinyl acetate emulsion obtained by emulsion-copolymerizing 30 to 200 parts by weight of a total modified starch comprising a starch saccharified product having a viscosity of 300 CPS.