JPH0578540A - Film formed from water-base resin dispersion - Google Patents

Abstract

PURPOSE:To provide the subject film having mechanical properties suitable for applications such as a coating material, an adhesive, a fiber processing agent, a paper processing agent, a medical material, and a cosmetic. CONSTITUTION:The objective film is formed from a water-base resin dispersion which contains a polyvinyl alcohol polymer and polymer particles having a glass transition point not higher than the service temp. and grafted with the polyvinyl alcohol polymer in a wt. ratio of (WPVA+Wg-PVA)/(WPAR-Wg-PVA) (wherein WPVA is the Wt. of the polyvinyl alcohol polymer; Wg-PVA is the wt. of the polyvinyl alcohol polymer grafted onto the polymer particles; and WPAR is the wt. of the polymer particles) of 0.01-0.3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a uniform film having high tensile strength and elastomeric properties which is useful for paints, adhesives, fiber processing agents, paper processing agents, medical materials, cosmetics and the like.

[0002]

2. Description of the Related Art In recent years,
In the field of polymer industry, from the viewpoint of resource saving, pollution prevention and safety, water-dispersion type resins are emphasized in place of solvent type resins which have been widely used conventionally. In particular, in the fields of paints, adhesives, fiber processing agents, paper processing agents, medical materials, cosmetics, etc., it has been earnestly desired to produce a film having useful mechanical properties from a water-dispersible resin. Most conventional water-dispersible resins are produced by emulsion polymerization, and usually several% of an emulsifier is used to stabilize the dispersion of polymer particles. Films made from this emulsion have weak mechanical strength due to the effect of emulsifiers present at the grain interfaces and are therefore used only in limited applications. Exceptionally, a film having relatively good mechanical properties can be obtained from an emulsion produced by emulsion polymerization of monomers such as vinyl carboxylates typified by vinyl acetate and vinyl chloride in the presence of polyvinyl alcohol. , It is not used in a wide range of applications due to the limitation of the monomers that can be used in this method.

As a method for overcoming the former drawback, research and development relating to a method for synthesizing a water-dispersible resin containing no emulsifier is increasing. For example, Yamazaki et al., “New Development and Problems of Synthetic Polymer Latex” (Chemical Industry Data (Tokyo Tech News), vol.13 (4), p3 (1978)) describes the soap-free emulsion polymerization method. However, the aqueous dispersion obtained by the soap-free emulsion polymerization method has not been put to practical use because the storage stability and mechanical strength are extremely poor. In addition, JP-A-63-
Although the mechanical strength of the film made from the self-dispersing aqueous vinyl resin shown in Japanese Patent No. 280702 is such that the mechanical properties are improved as compared with the film obtained from the dispersion made by the usual emulsion polymerization. Still not enough. In addition, films made by emulsion polymerization using polyvinyl alcohol and Ce salt (Otsuka et al., Polymer Chemistry, 25 , 375, 490 (1968), Yamashita et al., Polymers, 35 , 283 (1978)) , Shows strong film properties, but the amount of polyvinyl alcohol used is large (weight ratio of monomer to 0.316 or more),
It is an intermediate between latex film and solvent cast film. Therefore, the object of the present invention is to provide paints, adhesives,
An object of the present invention is to provide a film formed from a water-dispersible resin having mechanical properties useful for applications such as fiber processing agents, paper processing agents, medical materials, and cosmetics.

[0004]

As a result of intensive research to solve the above problems, the present inventors have found that by using a water-dispersible resin having a specific composition and structure, a paint, an adhesive, a fiber processing agent, The inventors have found that a film having mechanical properties useful for paper processing agents, medical materials, cosmetics and the like can be obtained, and completed the present invention. That is, the present invention comprises a polyvinyl alcohol-based polymer and a polymer particle having a polyvinyl alcohol-based polymer grafted on the surface thereof and having a glass transition point (Tg) of not higher than a normal temperature, represented by the following formula (1): The present invention provides a film formed by forming a water-dispersible resin having a weight ratio of polyvinyl alcohol polymer of 0.01 or more and less than 0.3.

Polyvinyl alcohol-based polymer weight ratio = (W _PVA + W _g-PVA ) / (W _PAR −W _g-PVA ) ... (1) (where W _PVA : weight of polyvinyl alcohol-based polymer, W _{g- (PVA} : weight of polyvinyl alcohol-based polymer grafted on polymer particles, W _PAR : weight of polymer particles.) A specific method for preparing the water-dispersible resin of the present invention is to have a mercapto group at the terminal. Using a polyvinyl alcohol polymer (which can be prepared by the method described in JP-A-59-187003) as an emulsion dispersion stabilizer, a radically polymerizable ethylenically unsaturated monomer or a diene monomer is used. A method of homoemulsion polymerization or emulsion copolymerization (see JP-A-60-197229), or an ethylenically unsaturated monomer capable of radical polymerization in the presence of a cerium salt in an aqueous solution of a polyvinyl alcohol polymer. Alone emulsion polymerization or emulsion copolymerization of the body or diene monomer
(See Polymer Chemistry, 25 , 375 (1968)) and the like. However, these methods do not limit the method for preparing the water-dispersible resin of the present invention.

In the method for preparing the water-dispersible resin of the present invention, the polymerization initiator used in the former method includes potassium bromate, potassium persulfate, ammonium persulfate, hydrogen peroxide and 2,2'- Azobis (2-amidinopropane) hydrochloride (trade name V-50: manufactured by Wako Pure Chemical Industries, Ltd.),
Water-soluble initiators such as azobiscyanovaleric acid may be mentioned.
However, these examples do not limit the above-mentioned initiators. Further, as the emulsion dispersion stabilizer used in the former method, it is preferable to use a polyvinyl alcohol-based polymer having a mercapto group at the terminal alone, but in some cases, conventionally known various anionic, cationic, nonionic properties. A surfactant or various water-soluble polymers can be appropriately used in combination. Also, the second method used in the latter method
As the cerium salt, cerium ammonium nitrate or cerium ammonium sulfate can be used. Examples of the radically polymerizable ethylenically unsaturated monomer or diene monomer used in the method for preparing the water-dispersible resin of the present invention include ethylene, propylene, olefins such as isobutylene, and dienes such as butadiene. Acrylic acid and its salts, acrylic acid esters, methacrylic acid and its salts, methacrylic acid esters, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide and their derivatives, vinyl ethers such as ethyl vinyl ether and butyl vinyl ether, and halogens such as vinyl chloride. Examples thereof include vinyl chlorides, styrene and derivatives thereof, and these monomers are homopolymerized or copolymerized. These examples do not limit the radically polymerizable ethylenically unsaturated monomer or diene monomer that can be used in the present invention.

The polyvinyl alcohol polymer used in the preparation of the water-dispersible resin of the present invention contains the following structural unit A and may further contain the following structural unit B, and the content of A is 100 to 50 mol%, preferably Is 100 to 70 mol%.

[0008]

[Chemical 1]

(However, R ¹ represents H or a hydrocarbon group having 1 to 6 carbon atoms, and R ² represents H or a hydrocarbon group having 1 to 20 carbon atoms.) This polyvinyl alcohol polymer is It is obtained by saponifying a polyvinyl ester polymer obtained by polymerizing a vinyl monomer mainly containing vinyl ester monomers by a conventional method. Any vinyl ester capable of radical polymerization can be used as the vinyl ester. For example, vinyl formate, vinyl acetate, vinyl propionate, vinyl laurate, vinyl stearate and the like can be mentioned. Among them, vinyl acetate is most preferable since it has the highest polymerizability. It is also possible to copolymerize the vinyl ester with a copolymerizable monomer. For example, ethylene, propylene, isobutylene, acrylic acid, methacrylic acid or salts thereof or alkyl esters thereof, itaconic acid, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, trimethyl-
(3-Acrylamido-3-dimethylpropyl) -ammonium chloride, ethyl vinyl ether, butyl vinyl ether, N-vinyl pyrrolidone, vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, vinyl sulfonic acid Examples thereof include sodium and sodium allylsulfonate.
The degree of polymerization of this polyvinyl alcohol polymer is preferably 3500 or less. The degree of saponification also differs depending on the type of other modifying groups and cannot be unambiguously determined, but usually the polyvinyl alcohol component is preferably 50 mol% or more, and from the viewpoint of water solubility, 70 mol% or more is preferable.

The glass transition point (Tg) of the polymer particles grafted with a polyvinyl alcohol-based polymer on the surface of the water-dispersible resin of the present invention needs to be kept at a normal temperature or lower, and Tg is kept at a predetermined temperature or lower. As a method, polymer Tg
Is selected to carry out homopolymerization by selecting a monomer whose temperature is below a predetermined temperature, a method of carrying out copolymerization by selecting a plurality of monomers so that Tg of the copolymer is below a predetermined temperature, and Tg being plastic to a polymer above a predetermined temperature. There is a method of adding an agent to make Tg lower than a predetermined temperature. Here, the normal temperature is a temperature at which the film of the present invention is handled, and is a temperature at which a film is formed or the film is used for an intended purpose. Normally, -5 ℃ ~ 70
℃, preferably 0 ℃ ~ 60 ℃, more preferably 5 ℃ ~ 50 ℃
Is. The particle size of the polymer particles grafted with a polyvinyl alcohol polymer on the surface of the water-dispersible resin of the present invention is 0.01 μm or more and 5 μm or less, preferably 0.05 μm or more and 1 μm or less.

The weight ratio of the polyvinyl alcohol polymer represented by the above formula (1) in the water-dispersible resin of the present invention is 0.01 or more.
It is less than 0.3, preferably 0.05 or more and 0.25 or less. If it is less than 0.01, a film having sufficient strength cannot be obtained, and if it is more than 0.3, the viscosity of the system increases and it becomes an intermediate between latex and polymer solution, and the characteristics of latex are lost. The composition ratio of the polyvinyl alcohol-based polymer in the water-dispersible resin of the present invention and the polyvinyl alcohol-based polymer grafted on the surface of the polymer particles is 0 _{g as} W _g-PVA / (W _PVA + W _g-PVA ). .
It is preferably 3 or more, and more preferably 0.5 or more. 0.
If it is less than 3, a film having good mechanical strength cannot be obtained.

The film of the present invention can be formed by a usual method using the water-dispersible resin obtained by the above method. Examples of the film forming method include a casting method and a method using an applicator. However, the above method does not limit the method for forming the film of the present invention.

[0013]

When the emulsion formed by blending the aqueous solution of polyvinyl alcohol polymer and ordinary polymer particles is formed into a film, the polyvinyl alcohol polymer phase and the polymer particle aggregate phase are usually phase-separated and a uniform film is not formed. .. However, the film of the present invention is a macroscopically uniform film. Further, as a result of analyzing the film of the present invention with a transmission electron microscope, it has a sea-island structure in which a polyvinyl alcohol polymer is microscopically a continuous phase and each polymer particle is a discontinuous phase. I understood. In order to form this sea-island structure, the film of the present invention is presumed to be macroscopically uniform. This is because the polyvinyl alcohol polymer grafted on the surface of the polymer particles acts as a protective colloid to prevent fusion between particles and has the same composition as the continuous phase, so that the polyvinyl alcohol polymer layer and the polymer particles are It is considered that and are compatible with each other. The porosity (percentage of voids to the total volume) when closely packed with rigid spheres of uniform particle size is 25.95%. Therefore, assuming that the polymer particles are spherical rigid bodies and their particle size is constant, even if the polymer particles are the closest packed, the volume of the continuous phase should be 25.95% or more based on the total solid content, the homogeneity should be uniform. No film is formed. However, even if the polymer particles according to the present invention are spherical particles having a substantially uniform particle diameter, the content of the polyvinyl alcohol polymer is 2% of the total solid content.
It forms a uniform film at normal temperature even with less than 5.95%. The reason is that the Tg of polymer particles
Is lower than the usual molding temperature, and it is thought that the continuous phase can be formed even with a small amount of polyvinyl alcohol-based polymer due to deformation during film formation.

If the latex contains a water-soluble polyvinyl alcohol-based polymer in a weight ratio of 0.3 or more relative to the latex particles, the viscosity of the system increases, and it is an intermediate product between the latex and the polymer solution. And the properties of latex are lost. In the present invention, since the content of the polyvinyl alcohol-based polymer is small, the viscosity of the system is low and the characteristics as a latex are not lost. The film of the present invention has higher film strength than an ordinary film formed using a water-dispersible resin and has physical properties like an elastomer. It is considered that this is because the continuous film of polyvinyl alcohol exhibited high film strength, while the discontinuous phase of polymer particles having a low Tg exhibited elastomeric physical properties.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In the examples, parts and% mean weight basis. Table 1 shows the analysis values of the degree of polymerization, the degree of saponification, and the mercapto group content of the polyvinyl alcohol polymers PVA-1 to PVA-7 used in the examples. In addition, from PVA-1 to PVA
-5 was synthesized and analyzed according to the method described in Japanese Patent Publication No. 3-24481.

[0016]

[Table 1]

Example 1 A glass polymerization container equipped with a reflux condenser, a thermometer, a stirring blade, and a nitrogen blowing port was charged with 5% polyvinyl alcohol (PVA).
-1) An aqueous solution (200 parts) was charged and the atmosphere was replaced with nitrogen for 30 minutes. After adjusting the pH to 4.9 with 0.1 N hydrochloric acid, stirring at 200 rpm, ethyl acrylate (40 parts), V-50 (0.2 parts)
Part) was added, the temperature was raised to 80 ° C., and polymerization was performed for 6 hours. Table 2 shows the charging conditions, Tg, PVA weight ratio, particle size, and PVA reaction rate. The pH of the produced emulsion was adjusted and then filtered through a 300-mesh wire net, but the amount of coagulation was slight. The filtered emulsion is applied on a PET (polyethylene terephthalate) film under the conditions of 23 ° C and 60% RH using an applicator manufactured by Nippon Rigaku Co., Ltd., and dried under the same conditions for 8 hours to obtain a film with a thickness of 0.05 ± 0.01 mm. Was produced. The physical properties of the film are
High-performance universal material testing machine (TE
NSILON UCT-100) was used to measure the tensile strength and Young's modulus. The measurement sample has a width of 10mm and a length of 3mm, 23 ℃, 60%
The measurement was performed under conditions of RH and a pulling speed of 200 mm / min. The results are shown in Table 4.

Examples 2 and 3 In the same manner as in Example 1, polymerization was carried out by changing the kinds and the amounts of the monomers, polyvinyl alcohol and initiator,
A film was prepared and the physical properties of the film were measured. Table 2 shows the charging conditions and Table 4 shows the physical properties of the film.

Example 4 5% by weight of polyvinyl alcohol was placed in a glass polymerization vessel equipped with a reflux condenser, a thermometer, a stirring blade, and a nitrogen blowing port.
An aqueous solution of (PVA-1) (200 parts) was charged, and the atmosphere was replaced with nitrogen for 30 minutes. The pH was adjusted to 4.9 with 0.1 N succinic acid, the temperature was raised to 80 ° C., and then the mixture was stirred at 200 rpm, and a mixture (20 parts) of n-butyl methacrylate and n-hexyl methacrylate in a weight ratio of 7: 3 was added. Ammonium sulfate (0.15 parts) was added. After 5 minutes, a mixture (20 parts) of n-butyl methacrylate and n-hexyl methacrylate having the same weight ratio was added dropwise over 1 hour. Thirty minutes after the start of dropping the mixture, an aqueous 1% ammonium persulfate solution (10 parts) was added dropwise over 30 minutes. After completion of dropping of the monomer and the initiator, heating and stirring were performed for 5 hours under the same conditions. Then, post-treatment was carried out in the same manner as in Example 1 to produce a film, and the physical properties of the film were measured. Table 2 shows the charging conditions and Table 4 shows the physical properties of the film.

Examples 5 to 9 Polymerization was carried out in the same manner as in Example 4 by changing the types and amounts of the monomers, polyvinyl alcohol and initiator,
A film was prepared and the physical properties of the film were measured. Table 2 shows the charging conditions and Table 4 shows the physical properties of the film.

Examples 10 to 12 Polymerization was carried out in the same manner as in Example 1 by changing the types of monomers, polyvinyl alcohol and initiator and the charged amount. Regarding Example 10, the film was formed at 45 ° C. and 60% RH, dried under the same condition for 8 hours, and then the physical properties of the film were measured under the same condition. For Examples 11 and 12, films were prepared under the same conditions as in Example 1 and the film physical properties were measured. Table 3 shows the charging conditions and the like and Table 4 shows the physical properties of the film.

Example 13 A 5% aqueous polyvinyl alcohol (PVA-3) solution (200 parts) was charged into a stainless steel autoclave equipped with a nitrogen inlet and a thermometer, and the atmosphere was replaced with nitrogen for 30 minutes. 0.1 N
Adjust the pH to 4.9 with malic acid and stir at 200 rpm,
Styrene (20 parts) was charged. Then butadiene (20
Part) is press-fitted from a pressure-resistant measuring instrument and heated to 70 ° C, then 1%
Polymerization was initiated by pressurizing an aqueous potassium persulfate solution (0.32 part). After 24 hours, it was confirmed that the pressure had dropped, and the polymerization was terminated. Then, after-treatment was performed in the same manner as in Example 1 to produce a film. Table 3 shows the charging conditions and the like and Table 4 shows the physical properties of the film.

Example 14 A glass polymerization container equipped with a reflux condenser, a thermometer, a stirring blade, and a nitrogen blowing port was charged with 5% polyvinyl alcohol (PVA).
-6) An aqueous solution (200 parts) was charged and the atmosphere was replaced with nitrogen for 30 minutes. While stirring at 200 rpm, n-butyl acrylate (40 parts) was added, Ce (NH ₄ ) ₂ (NO ₃ ) ₆ (0.8 parts) was added, and the mixture was stirred at room temperature for 6 hours. After the completion of the polymerization, it was treated with an ion exchange resin to remove the Ce salt. Then, after-treatment was performed in the same manner as in Example 1 to produce a film. Table 3 shows the preparation conditions
Table 4 shows the film physical properties.

Example 15 In the same manner as in Example 14, the monomer, the kind of polyvinyl alcohol and the charged amount of Ce (NH ₄ ) ₂ (NO ₃ ) ₆ were changed, and the polymerization was carried out at a polymerization temperature of 40 ° C. to obtain a film. It was created. Table 3 shows the charging conditions and the like and Table 4 shows the physical properties of the film.

Example 16 After leaving the film of Example 7 at 10 ° C. and 60% RH for 8 hours,
The physical properties of the film were measured under the same conditions. The results are shown in Table 4. Example 17 After leaving the film of Example 3 at 45 ° C. and 60% RH for 8 hours,
The physical properties of the film were measured under the same conditions. The results are shown in Table 4.

Comparative Example 1 A 0.3% aqueous solution of sodium dodecylbenzenesulfonate (200 parts) was added to a glass polymerization vessel equipped with a reflux condenser, a thermometer, a stirring blade and a nitrogen blowing port, and the atmosphere was replaced with nitrogen for 30 minutes. .. Next, n-butyl acrylate (10 parts) and ammonium persulfate (0.8 parts) were added, and the temperature was raised to 80 ° C. Then, n-butyl acrylate (140 parts) was added dropwise over 1 hour, and after completion of the addition, the mixture was heated and stirred for 5 hours. The resulting emulsion and 10% by weight of polyvinyl alcohol (PVA-7)
When a mixture of the aqueous solutions in a weight ratio of 1: 1 was applied and dried, a uniform film could not be obtained because the acrylic resin and polyvinyl alcohol were phase-separated.

Comparative Example 2 The following experiment was conducted for the purpose of measuring the physical properties of a methacrylic resin cast film and comparing it with Example 1. A glass polymerization vessel equipped with a reflux condenser, a thermometer, a stirring blade, and a nitrogen inlet was placed in a methyl ethyl ketone (50 parts), n-butyl methacrylate (35 parts), and n-hexyl methacrylate (15 parts).
Part) was added and nitrogen substitution was performed for 30 minutes. Next, V-59 (manufactured by Wako Pure Chemical Industries; 0.2 part) was added, and the mixture was heated with stirring at 80 ° C for 10 hours. The obtained polymer solution was cast as it was to obtain a film. Table 3 shows the charging conditions and the like and Table 4 shows the physical properties of the film.

Comparative Example 3 The following experiment was carried out for the purpose of setting an example in which the Tg of the polymer particles was at or above the normal temperature. When styrene was polymerized in the same manner as in Example 1 to form a film,
The film became cloudy and very brittle, and the physical properties of the film could not be measured. The charging conditions and the like are shown in Table 3.

Comparative Example 4 The film of Example 5 was allowed to stand at 5 ° C. and 60% RH for 8 hours,
When the physical properties of the film were tried to be measured, the film became very brittle and could not be measured. Comparative Example 5 When the emulsion of Example 10 was tried to be formed into a film at 23 ° C. and 60% RH, a single film was not formed and the film physical properties could not be measured.

[0030]

[Table 2]

[0031]

[Table 3]

Note) * 1: Unsaturated monomer: batch charge Unsaturated monomer: drop charge * 2: When the amount of initiator is divided into two stages, upper: batch charge, lower: drop charge * 3: Set Tg is the Fox equation ((2) equation; TGFox: Bull. Am. Ph.
ys. Soc., II, 1 , 123 (1956)). The Tg of each polymer can be found in the Polymer Hand book (JohnWiley & Son
s, Inc.).

[0033]

[Equation 1]

(However, Tg: Tg of copolymer, W ₁ , W ₂ : weight fraction of monomers 1 and 2, Tg ₁ , Tg ₂ : monomer 1 and 2
Indicates Tg. ) * 4: PVA weight ratio was calculated by the following equation (3).

[0035]

[Equation 2]

* 5: The particle size of the emulsion was measured using a particle size distribution analyzer N-4 manufactured by Coulter and / or a transmission electron microscope. * 6: The PVA reaction rate is the method of Otsuka et al. (Otsuka et al., Polymer Chemistry,
25 , 375 (1968)) and calculated according to equation (4).

[0037]

[Equation 3]

In each of Examples 1 to 15 and Comparative Examples 1 to 3, the polymerization proceeded almost quantitatively.

[0039]

[Table 4]

Claims (3)

[Claims] 1. A polyvinyl alcohol represented by the following formula (1), which comprises a polyvinyl alcohol-based polymer and polymer particles having a glass transition point (Tg) not higher than a normal temperature and having a surface grafted with the polyvinyl alcohol-based polymer. A film obtained by forming a water-dispersible resin having a weight ratio of an alcohol-based polymer of 0.01 or more and less than 0.3. Polyvinyl alcohol-based polymer weight ratio = (W _PVA + W _g-PVA ) / (W _PAR- W _g-PVA ) ... (1) (W _PVA : weight of polyvinyl alcohol-based polymer, W _g-PVA : polymer Weight of polyvinyl alcohol-based polymer grafted on particles, W _PAR : Represents the weight of polymer particles.) 2. A water-dispersible resin using a polyvinyl alcohol-based polymer having a mercapto group at its terminal as an emulsion dispersion stabilizer, and a homopolymerization of a radically polymerizable ethylenically unsaturated monomer or a diene-based monomer. The film according to claim 1, which is a water-dispersible resin obtained by emulsion copolymerization. 3. A water-dispersible resin, which is an emulsion polymerization of a radical-polymerizable ethylenically unsaturated monomer or diene monomer in the presence of a cerium salt in an aqueous solution of a polyvinyl alcohol polymer. The film according to claim 1, which is a water-dispersible resin obtained by emulsion copolymerization.